Choose any three.
SQLite Requirement Matrix Details
foreignkeys.html
Index Summary Markup Original
R-04042-24825-64259-53667-46708-22366-11905-57675 tcl slt th3 src
To do so, a foreign key definition may be added by modifying the declaration of the track table to the following:
CREATE TABLE track( trackid INTEGER, trackname TEXT, trackartist INTEGER, FOREIGN KEY(trackartist) REFERENCES artist(artistid) );
tcl/e_fkey.test:258 th3/req1/foreignkeys01.test:11
/* IMP: R-04042-24825 */
# EVIDENCE-OF: R-04042-24825 To do so, a foreign key definition may be # added by modifying the declaration of the track table to the # following: CREATE TABLE track( trackid INTEGER, trackname TEXT, # trackartist INTEGER, FOREIGN KEY(trackartist) REFERENCES # artist(artistid) );
R-61362-32087-29784-51692-52137-61704-15338-45644 tcl slt th3 src
Attempting to insert a row into the track table that does not correspond to any row in the artist table will fail,
tcl/e_fkey.test:280 th3/req1/foreignkeys01.test:29
/* IMP: R-61362-32087 */
# EVIDENCE-OF: R-61362-32087 Attempting to insert a row into the track # table that does not correspond to any row in the artist table will # fail,
R-24401-52400-49114-60456-18821-28705-54480-01087 tcl slt th3 src
as will attempting to delete a row from the artist table when there exist dependent rows in the track table
tcl/e_fkey.test:299 th3/req1/foreignkeys01.test:52
/* IMP: R-24401-52400 */
# EVIDENCE-OF: R-24401-52400 as will attempting to delete a row from the # artist table when there exist dependent rows in the track table
R-23980-48859-56951-38852-38346-56715-55568-02993 tcl slt th3 src
There is one exception: if the foreign key column in the track table is NULL, then no corresponding entry in the artist table is required.
tcl/e_fkey.test:316 th3/req1/foreignkeys01.test:60
/* IMP: R-23980-48859 */
# EVIDENCE-OF: R-23980-48859 There is one exception: if the foreign key # column in the track table is NULL, then no corresponding entry in the # artist table is required.
R-52486-21352-15520-42418-18389-29845-28843-27004 tcl slt th3 src
Expressed in SQL, this means that for every row in the track table, the following expression evaluates to true:
trackartist IS NULL OR EXISTS(SELECT 1 FROM artist WHERE artistid=trackartist)
tcl/e_fkey.test:353 th3/req1/foreignkeys01.test:100 th3/req1/foreignkeys01.test:133 th3/req1/foreignkeys01.test:165 th3/req1/foreignkeys01.test:41 th3/req1/foreignkeys01.test:70
/* IMP: R-52486-21352 */
# EVIDENCE-OF: R-52486-21352 Expressed in SQL, this means that for every # row in the track table, the following expression evaluates to true: # trackartist IS NULL OR EXISTS(SELECT 1 FROM artist WHERE # artistid=trackartist)
R-42412-59321-17229-61863-37154-26359-45547-07737 tcl slt th3 src
Tip: If the application requires a stricter relationship between artist and track, where NULL values are not permitted in the trackartist column, simply add the appropriate "NOT NULL" constraint to the schema.
tcl/e_fkey.test:408 th3/req1/foreignkeys02.test:11
/* IMP: R-42412-59321 */
# EVIDENCE-OF: R-42412-59321 Tip: If the application requires a stricter # relationship between artist and track, where NULL values are not # permitted in the trackartist column, simply add the appropriate "NOT # NULL" constraint to the schema.
R-16127-35442-25332-57824-03233-02546-37060-55461 tcl slt th3 src
The following SQLite command-line session illustrates the effect of the foreign key constraint added to the track table:
sqlite> SELECT * FROM artist; artistid artistname -------- ----------------- 1 Dean Martin 2 Frank Sinatra sqlite> SELECT * FROM track; trackid trackname trackartist ------- ----------------- ----------- 11 That's Amore 1 12 Christmas Blues 1 13 My Way 2 sqlite> -- This fails because the value inserted into the trackartist column (3) sqlite> -- does not correspond to row in the artist table. sqlite> INSERT INTO track VALUES(14, 'Mr. Bojangles', 3); SQL error: foreign key constraint failed sqlite> -- This succeeds because a NULL is inserted into trackartist. A sqlite> -- corresponding row in the artist table is not required in this case. sqlite> INSERT INTO track VALUES(14, 'Mr. Bojangles', NULL); sqlite> -- Trying to modify the trackartist field of the record after it has sqlite> -- been inserted does not work either, since the new value of trackartist (3) sqlite> -- Still does not correspond to any row in the artist table. sqlite> UPDATE track SET trackartist = 3 WHERE trackname = 'Mr. Bojangles'; SQL error: foreign key constraint failed sqlite> -- Insert the required row into the artist table. It is then possible to sqlite> -- update the inserted row to set trackartist to 3 (since a corresponding sqlite> -- row in the artist table now exists). sqlite> INSERT INTO artist VALUES(3, 'Sammy Davis Jr.'); sqlite> UPDATE track SET trackartist = 3 WHERE trackname = 'Mr. Bojangles'; sqlite> -- Now that "Sammy Davis Jr." (artistid = 3) has been added to the database, sqlite> -- it is possible to INSERT new tracks using this artist without violating sqlite> -- the foreign key constraint: sqlite> INSERT INTO track VALUES(15, 'Boogie Woogie', 3);
tcl/e_fkey.test:433 th3/req1/foreignkeys01.test:111 th3/req1/foreignkeys01.test:81
/* IMP: R-16127-35442 */
# EVIDENCE-OF: R-16127-35442 The following SQLite command-line session # illustrates the effect of the foreign key constraint added to the # track table: sqlite> SELECT * FROM artist; artistid artistname # -------- ----------------- 1 Dean Martin 2 Frank Sinatra sqlite> # SELECT * FROM track; trackid trackname trackartist ------- # ----------------- ----------- 11 That's Amore 1 12 Christmas Blues 1 # 13 My Way 2 sqlite> -- This fails because the value inserted into # the trackartist column (3) sqlite> -- does not correspond to row in # the artist table. sqlite> INSERT INTO track VALUES(14, 'Mr. # Bojangles', 3); SQL error: foreign key constraint failed sqlite> -- # This succeeds because a NULL is inserted into trackartist. A # sqlite> -- corresponding row in the artist table is not required in # this case. sqlite> INSERT INTO track VALUES(14, 'Mr. Bojangles', # NULL); sqlite> -- Trying to modify the trackartist field of the # record after it has sqlite> -- been inserted does not work either, # since the new value of trackartist (3) sqlite> -- Still does not # correspond to any row in the artist table. sqlite> UPDATE track SET # trackartist = 3 WHERE trackname = 'Mr. Bojangles'; SQL error: foreign # key constraint failed sqlite> -- Insert the required row into the # artist table. It is then possible to sqlite> -- update the inserted # row to set trackartist to 3 (since a corresponding sqlite> -- row # in the artist table now exists). sqlite> INSERT INTO artist # VALUES(3, 'Sammy Davis Jr.'); sqlite> UPDATE track SET trackartist # = 3 WHERE trackname = 'Mr. Bojangles'; sqlite> -- Now that "Sammy # Davis Jr." (artistid = 3) has been added to the database, sqlite> # -- it is possible to INSERT new tracks using this artist without # violating sqlite> -- the foreign key constraint: sqlite> INSERT # INTO track VALUES(15, 'Boogie Woogie', 3);
R-15958-50233-58629-08203-04879-28676-03150-11250 tcl slt th3 src
As you would expect, it is not possible to manipulate the database to a state that violates the foreign key constraint by deleting or updating rows in the artist table either:
sqlite> -- Attempting to delete the artist record for "Frank Sinatra" fails, since
sqlite> -- the track table contains a row that refer to it.
sqlite> DELETE FROM artist WHERE artistname = 'Frank Sinatra';
SQL error: foreign key constraint failed
sqlite> -- Delete all the records from the track table that refer to the artist
sqlite> -- "Frank Sinatra". Only then is it possible to delete the artist.
sqlite> DELETE FROM track WHERE trackname = 'My Way';
sqlite> DELETE FROM artist WHERE artistname = 'Frank Sinatra';
sqlite> -- Try to update the artistid of a row in the artist table while there
sqlite> -- exists records in the track table that refer to it.
sqlite> UPDATE artist SET artistid=4 WHERE artistname = 'Dean Martin';
SQL error: foreign key constraint failed
sqlite> -- Once all the records that refer to a row in the artist table have
sqlite> -- been deleted, it is possible to modify the artistid of the row.
sqlite> DELETE FROM track WHERE trackname IN('That''s Amore', 'Christmas Blues');
sqlite> UPDATE artist SET artistid=4 WHERE artistname = 'Dean Martin';
tcl/e_fkey.test:477 th3/req1/foreignkeys01.test:144
/* IMP: R-15958-50233 */
# EVIDENCE-OF: R-15958-50233 As you would expect, it is not possible to
# manipulate the database to a state that violates the foreign key
# constraint by deleting or updating rows in the artist table either:
# sqlite> -- Attempting to delete the artist record for "Frank
# Sinatra" fails, since sqlite> -- the track table contains a row
# that refer to it. sqlite> DELETE FROM artist WHERE artistname =
# 'Frank Sinatra'; SQL error: foreign key constraint failed sqlite>
# -- Delete all the records from the track table that refer to the
# artist sqlite> -- "Frank Sinatra". Only then is it possible to
# delete the artist. sqlite> DELETE FROM track WHERE trackname = 'My
# Way'; sqlite> DELETE FROM artist WHERE artistname = 'Frank
# Sinatra'; sqlite> -- Try to update the artistid of a row in the
# artist table while there sqlite> -- exists records in the track
# table that refer to it. sqlite> UPDATE artist SET artistid=4 WHERE
# artistname = 'Dean Martin'; SQL error: foreign key constraint failed
# sqlite> -- Once all the records that refer to a row in the artist
# table have sqlite> -- been deleted, it is possible to modify the
# artistid of the row. sqlite> DELETE FROM track WHERE trackname
# IN('That''s Amore', 'Christmas Blues'); sqlite> UPDATE artist SET
# artistid=4 WHERE artistname = 'Dean Martin';
R-32809-14620-63808-12852-40065-57653-46928-34414 tcl slt th3 src
The parent key must be a named column or columns in the parent table, not the rowid.
th3/req1/foreignkeys03.test:11
/* IMP: R-32809-14620 */
# EVIDENCE-OF: R-32809-14620 The parent key must be a named column or # columns in the parent table, not the rowid.
R-56032-24923-44084-62651-61742-23069-00366-25575 tcl slt th3 src
The foreign key constraint is satisfied if for each row in the child table either one or more of the child key columns are NULL, or there exists a row in the parent table for which each parent key column contains a value equal to the value in its associated child key column.
tcl/e_fkey.test:506 th3/req1/foreignkeys03.test:45
/* IMP: R-56032-24923 */
# EVIDENCE-OF: R-56032-24923 The foreign key constraint is satisfied if # for each row in the child table either one or more of the child key # columns are NULL, or there exists a row in the parent table for which # each parent key column contains a value equal to the value in its # associated child key column.
R-57765-12380-65473-27490-60483-53059-23435-27202 tcl slt th3 src
In the above paragraph, the term "equal" means equal when values are compared using the rules specified here.
tcl/e_fkey.test:515 th3/req1/foreignkeys03.test:88
/* IMP: R-57765-12380 */
# EVIDENCE-OF: R-57765-12380 In the above paragraph, the term "equal" # means equal when values are compared using the rules specified here.
R-15796-47513-29721-16055-11683-21050-32207-60873 tcl slt th3 src
When comparing text values, the collating sequence associated with the parent key column is always used.
tcl/e_fkey.test:557 th3/req1/foreignkeys03.test:120
/* IMP: R-15796-47513 */
# EVIDENCE-OF: R-15796-47513 When comparing text values, the collating # sequence associated with the parent key column is always used.
R-04240-13860-65376-64948-20761-30630-14399-44960 tcl slt th3 src
When comparing values, if the parent key column has an affinity, then that affinity is applied to the child key value before the comparison is performed.
tcl/e_fkey.test:588 th3/req1/foreignkeys03.test:141
/* IMP: R-04240-13860 */
# EVIDENCE-OF: R-04240-13860 When comparing values, if the parent key # column has an affinity, then that affinity is applied to the child key # value before the comparison is performed.
R-37672-59189-62965-02252-24561-10805-11427-09542 tcl slt th3 src
In order to use foreign key constraints in SQLite, the library must be compiled with neither SQLITE_OMIT_FOREIGN_KEY nor SQLITE_OMIT_TRIGGER defined.
tcl/e_fkey.test:51 th3/req1/foreignkeys05.test:30
/* IMP: R-37672-59189 */
# EVIDENCE-OF: R-37672-59189 In order to use foreign key constraints in # SQLite, the library must be compiled with neither # SQLITE_OMIT_FOREIGN_KEY nor SQLITE_OMIT_TRIGGER defined.
R-10109-20452-53276-41872-63667-11760-57644-25670 tcl slt th3 src
If SQLITE_OMIT_TRIGGER is defined but SQLITE_OMIT_FOREIGN_KEY is not, then SQLite behaves as it did prior to version 3.6.19 (2009-10-14) - foreign key definitions are parsed and may be queried using PRAGMA foreign_key_list, but foreign key constraints are not enforced.
tcl/e_fkey.test:72 th3/req1/foreignkeys05.test:34
/* IMP: R-10109-20452 */
# EVIDENCE-OF: R-10109-20452 If SQLITE_OMIT_TRIGGER is defined but # SQLITE_OMIT_FOREIGN_KEY is not, then SQLite behaves as it did prior to # version 3.6.19 (2009-10-14) - foreign key definitions are parsed and # may be queried using PRAGMA foreign_key_list, but foreign key # constraints are not enforced.
R-22567-44039-44321-46904-30045-11816-43845-22039 tcl slt th3 src
The PRAGMA foreign_keys command is a no-op in this configuration.
tcl/e_fkey.test:81 th3/req1/foreignkeys05.test:40
/* IMP: R-22567-44039 */
# EVIDENCE-OF: R-22567-44039 The PRAGMA foreign_keys command is a no-op # in this configuration.
R-58428-36660-63931-61833-12651-58158-26648-39835 tcl slt th3 src
If OMIT_FOREIGN_KEY is defined, then foreign key definitions cannot even be parsed (attempting to specify a foreign key definition is a syntax error).
tcl/e_fkey.test:115 th3/req1/foreignkeys05.test:53
/* IMP: R-58428-36660 */
# EVIDENCE-OF: R-58428-36660 If OMIT_FOREIGN_KEY is defined, then # foreign key definitions cannot even be parsed (attempting to specify a # foreign key definition is a syntax error).
R-07280-60510-42023-64617-40990-52816-04160-12840 tcl slt th3 src
Assuming the library is compiled with foreign key constraints enabled, it must still be enabled by the application at runtime, using the PRAGMA foreign_keys command.
tcl/e_fkey.test:149 th3/req1/foreignkeys04.test:11
/* IMP: R-07280-60510 */
# EVIDENCE-OF: R-07280-60510 Assuming the library is compiled with # foreign key constraints enabled, it must still be enabled by the # application at runtime, using the PRAGMA foreign_keys command.
R-44261-39702-04875-31790-36524-45169-57836-16173 tcl slt th3 src
Foreign key constraints are disabled by default (for backwards compatibility), so must be enabled separately for each database connection.
tcl/e_fkey.test:155 th3/req1/foreignkeys04.test:15
/* IMP: R-44261-39702 */
# EVIDENCE-OF: R-44261-39702 Foreign key constraints are disabled by # default (for backwards compatibility), so must be enabled separately # for each database connection.
R-08013-37737-04179-14029-08100-20980-22992-19882 tcl slt th3 src
The application can also use a PRAGMA foreign_keys statement to determine if foreign keys are currently enabled.
tcl/e_fkey.test:183 th3/req1/foreignkeys04.test:52
/* IMP: R-08013-37737 */
# EVIDENCE-OF: R-08013-37737 The application can also use a PRAGMA # foreign_keys statement to determine if foreign keys are currently # enabled.
R-11255-19907-56460-39957-30226-19999-22429-23256 tcl slt th3 src
The following command-line session demonstrates this:
sqlite> PRAGMA foreign_keys; 0 sqlite> PRAGMA foreign_keys = ON; sqlite> PRAGMA foreign_keys; 1 sqlite> PRAGMA foreign_keys = OFF; sqlite> PRAGMA foreign_keys; 0
tcl/e_fkey.test:190 th3/req1/foreignkeys04.test:56
/* IMP: R-11255-19907 */
# EVIDENCE-OF: R-11255-19907 The following command-line session # demonstrates this: sqlite> PRAGMA foreign_keys; 0 sqlite> PRAGMA # foreign_keys = ON; sqlite> PRAGMA foreign_keys; 1 sqlite> PRAGMA # foreign_keys = OFF; sqlite> PRAGMA foreign_keys; 0
R-41784-13339-39195-36557-35011-50589-62735-17221 tcl slt th3 src
Tip: If the command "PRAGMA foreign_keys" returns no data instead of a single row containing "0" or "1", then the version of SQLite you are using does not support foreign keys (either because it is older than 3.6.19 or because it was compiled with SQLITE_OMIT_FOREIGN_KEY or SQLITE_OMIT_TRIGGER defined).
tcl/e_fkey.test:84 th3/req1/foreignkeys05.test:11
/* IMP: R-41784-13339 */
# EVIDENCE-OF: R-41784-13339 Tip: If the command "PRAGMA foreign_keys" # returns no data instead of a single row containing "0" or "1", then # the version of SQLite you are using does not support foreign keys # (either because it is older than 3.6.19 or because it was compiled # with SQLITE_OMIT_FOREIGN_KEY or SQLITE_OMIT_TRIGGER defined).
R-46649-58537-03180-36291-48705-13434-30415-43306 tcl slt th3 src
It is not possible to enable or disable foreign key constraints in the middle of a multi-statement transaction (when SQLite is not in autocommit mode). Attempting to do so does not return an error; it simply has no effect.
tcl/e_fkey.test:213 th3/req1/foreignkeys06.test:11
/* IMP: R-46649-58537 */
# EVIDENCE-OF: R-46649-58537 It is not possible to enable or disable # foreign key constraints in the middle of a multi-statement transaction # (when SQLite is not in autocommit mode). Attempting to do so does not # return an error; it simply has no effect.
R-13435-26311-61176-01189-39199-58705-21930-17615 tcl slt th3 src
Usually, the parent key of a foreign key constraint is the primary key of the parent table. If they are not the primary key, then the parent key columns must be collectively subject to a UNIQUE constraint or have a UNIQUE index.
tcl/e_fkey.test:623 th3/req1/foreignkeys07.test:11
/* IMP: R-13435-26311 */
# EVIDENCE-OF: R-13435-26311 Usually, the parent key of a foreign key # constraint is the primary key of the parent table. If they are not the # primary key, then the parent key columns must be collectively subject # to a UNIQUE constraint or have a UNIQUE index.
R-00376-39212-00900-22873-65373-47922-05493-41094 tcl slt th3 src
If the parent key columns have a UNIQUE index, then that index must use the collation sequences that are specified in the CREATE TABLE statement for the parent table.
tcl/e_fkey.test:633 th3/req1/foreignkeys07.test:16
/* IMP: R-00376-39212 */
# EVIDENCE-OF: R-00376-39212 If the parent key columns have a UNIQUE # index, then that index must use the collation sequences that are # specified in the CREATE TABLE statement for the parent table.
R-27484-01467-40660-08782-16756-57898-53117-01697 tcl slt th3 src
For example,
CREATE TABLE parent(a PRIMARY KEY, b UNIQUE, c, d, e, f); CREATE UNIQUE INDEX i1 ON parent(c, d); CREATE INDEX i2 ON parent(e); CREATE UNIQUE INDEX i3 ON parent(f COLLATE nocase); CREATE TABLE child1(f, g REFERENCES parent(a)); -- Ok CREATE TABLE child2(h, i REFERENCES parent(b)); -- Ok CREATE TABLE child3(j, k, FOREIGN KEY(j, k) REFERENCES parent(c, d)); -- Ok CREATE TABLE child4(l, m REFERENCES parent(e)); -- Error! CREATE TABLE child5(n, o REFERENCES parent(f)); -- Error! CREATE TABLE child6(p, q, FOREIGN KEY(p, q) REFERENCES parent(b, c)); -- Error! CREATE TABLE child7(r REFERENCES parent(c)); -- Error!
The foreign key constraints created as part of tables child1, child2 and child3 are all fine.
tcl/e_fkey.test:671 th3/req1/foreignkeys07.test:22
/* IMP: R-27484-01467 */
# EVIDENCE-OF: R-27484-01467 For example, CREATE TABLE parent(a PRIMARY # KEY, b UNIQUE, c, d, e, f); CREATE UNIQUE INDEX i1 ON parent(c, d); # CREATE INDEX i2 ON parent(e); CREATE UNIQUE INDEX i3 ON parent(f # COLLATE nocase); CREATE TABLE child1(f, g REFERENCES parent(a)); -- Ok # CREATE TABLE child2(h, i REFERENCES parent(b)); -- Ok CREATE TABLE # child3(j, k, FOREIGN KEY(j, k) REFERENCES parent(c, d)); -- Ok CREATE # TABLE child4(l, m REFERENCES parent(e)); -- Error! CREATE TABLE # child5(n, o REFERENCES parent(f)); -- Error! CREATE TABLE child6(p, q, # FOREIGN KEY(p, q) REFERENCES parent(b, c)); -- Error! CREATE TABLE # child7(r REFERENCES parent(c)); -- Error! The foreign key constraints # created as part of tables child1, child2 and child3 are all fine.
R-51039-44840-65130-09775-42940-11077-05048-04287 tcl slt th3 src
The foreign key declared as part of table child4 is an error because even though the parent key column is indexed, the index is not UNIQUE.
tcl/e_fkey.test:677 th3/req1/foreignkeys07.test:57
/* IMP: R-51039-44840 */
# EVIDENCE-OF: R-51039-44840 The foreign key declared as part of table # child4 is an error because even though the parent key column is # indexed, the index is not UNIQUE.
R-01060-48788-51013-07543-20121-01838-30879-37400 tcl slt th3 src
The foreign key for table child5 is an error because even though the parent key column has a unique index, the index uses a different collating sequence.
tcl/e_fkey.test:683 th3/req1/foreignkeys07.test:66
/* IMP: R-01060-48788 */
# EVIDENCE-OF: R-01060-48788 The foreign key for table child5 is an # error because even though the parent key column has a unique index, # the index uses a different collating sequence.
R-63088-37469-41348-62985-35702-04852-27256-05198 tcl slt th3 src
Tables child6 and child7 are incorrect because while both have UNIQUE indices on their parent keys, the keys are not an exact match to the columns of a single UNIQUE index.
tcl/e_fkey.test:689 th3/req1/foreignkeys07.test:74
/* IMP: R-63088-37469 */
# EVIDENCE-OF: R-63088-37469 Tables child6 and child7 are incorrect # because while both have UNIQUE indices on their parent keys, the keys # are not an exact match to the columns of a single UNIQUE index.
R-45488-08504-64399-03603-60147-65359-06274-60393 tcl slt th3 src
If the database schema contains foreign key errors that require looking at more than one table definition to identify, then those errors are not detected when the tables are created.
tcl/e_fkey.test:736 th3/req1/foreignkeys07.test:85
/* IMP: R-45488-08504 */
# EVIDENCE-OF: R-45488-08504 If the database schema contains foreign key # errors that require looking at more than one table definition to # identify, then those errors are not detected when the tables are # created.
R-48391-38472-46406-48874-31358-29787-61398-48182 tcl slt th3 src
Instead, such errors prevent the application from preparing SQL statements that modify the content of the child or parent tables in ways that use the foreign keys.
tcl/e_fkey.test:741 th3/req1/foreignkeys07.test:91
/* IMP: R-48391-38472 */
# EVIDENCE-OF: R-48391-38472 Instead, such errors prevent the # application from preparing SQL statements that modify the content of # the child or parent tables in ways that use the foreign keys.
R-03108-63659-37525-03634-22905-61973-06931-63842 tcl slt th3 src
The English language error message for foreign key DML errors is usually "foreign key mismatch" but can also be "no such table" if the parent table does not exist.
tcl/e_fkey.test:745 th3/req1/foreignkeys07.test:97
/* IMP: R-03108-63659 */
# EVIDENCE-OF: R-03108-63659 The English language error message for # foreign key DML errors is usually "foreign key mismatch" but can also # be "no such table" if the parent table does not exist.
R-35763-48267-24179-20441-32559-50420-39179-45580 tcl slt th3 src
Foreign key DML errors are reported if:
- The parent table does not exist, or
- The parent key columns named in the foreign key constraint do not exist, or
- The parent key columns named in the foreign key constraint are not the primary key of the parent table and are not subject to a unique constraint using collating sequence specified in the CREATE TABLE, or
- The child table references the primary key of the parent without specifying the primary key columns and the number of primary key columns in the parent do not match the number of child key columns.
tcl/e_fkey.test:749 th3/req1/foreignkeys07.test:109
/* IMP: R-35763-48267 */
# EVIDENCE-OF: R-35763-48267 Foreign key DML errors are reported if: The # parent table does not exist, or The parent key columns named in the # foreign key constraint do not exist, or The parent key columns named # in the foreign key constraint are not the primary key of the parent # table and are not subject to a unique constraint using collating # sequence specified in the CREATE TABLE, or The child table references # the primary key of the parent without specifying the primary key # columns and the number of primary key columns in the parent do not # match the number of child key columns.
R-19353-43643-11289-35798-30332-46906-60350-15505 tcl slt th3 src
The last bullet above is illustrated by the following:
CREATE TABLE parent2(a, b, PRIMARY KEY(a,b)); CREATE TABLE child8(x, y, FOREIGN KEY(x,y) REFERENCES parent2); -- Ok CREATE TABLE child9(x REFERENCES parent2); -- Error! CREATE TABLE child10(x,y,z, FOREIGN KEY(x,y,z) REFERENCES parent2); -- Error!
tcl/e_fkey.test:818 th3/req1/foreignkeys07.test:121
/* IMP: R-19353-43643 */
# EVIDENCE-OF: R-19353-43643 The last bullet above is illustrated by the # following: CREATE TABLE parent2(a, b, PRIMARY KEY(a,b)); CREATE TABLE # child8(x, y, FOREIGN KEY(x,y) REFERENCES parent2); -- Ok CREATE TABLE # child9(x REFERENCES parent2); -- Error! CREATE TABLE child10(x,y,z, # FOREIGN KEY(x,y,z) REFERENCES parent2); -- Error!
R-23682-59820-57074-21944-19735-61329-41044-60872 tcl slt th3 src
By contrast, if foreign key errors can be recognized simply by looking at the definition of the child table and without having to consult the parent table definition, then the CREATE TABLE statement for the child table fails.
tcl/e_fkey.test:866 th3/req1/foreignkeys08.test:11
/* IMP: R-23682-59820 */
# EVIDENCE-OF: R-23682-59820 By contrast, if foreign key errors can be # recognized simply by looking at the definition of the child table and # without having to consult the parent table definition, then the CREATE # TABLE statement for the child table fails.
R-33883-28833-60318-48575-53923-47015-06615-40154 tcl slt th3 src
Foreign key DDL errors are reported regardless of whether or not foreign key constraints are enabled when the table is created.
tcl/e_fkey.test:873 th3/req1/foreignkeys08.test:16
/* IMP: R-33883-28833 */
# EVIDENCE-OF: R-33883-28833 Foreign key DDL errors are reported # regardless of whether or not foreign key constraints are enabled when # the table is created.
R-15417-28014-30557-42534-17582-00197-65121-60035 tcl slt th3 src
Indices are not required for child key columns
tcl/e_fkey.test:931 th3/req1/foreignkeys07.test:20
/* IMP: R-15417-28014 */
# EVIDENCE-OF: R-15417-28014 Indices are not required for child key # columns
R-00279-52283-49814-15354-28909-18424-55374-18430 tcl slt th3 src
Returning to the example in section 1, each time an application deletes a row from the artist table (the parent table), it performs the equivalent of the following SELECT statement to search for referencing rows in the track table (the child table).
SELECT rowid FROM track WHERE trackartist = ?
where ? in the above is replaced with the value of the artistid column of the record being deleted from the artist table (recall that the trackartist column is the child key and the artistid column is the parent key).
tcl/e_fkey.test:965 th3/req1/foreignkeys10.test:11
/* IMP: R-00279-52283 */
# EVIDENCE-OF: R-00279-52283 Returning to the example in section 1, each # time an application deletes a row from the artist table (the parent # table), it performs the equivalent of the following SELECT statement # to search for referencing rows in the track table (the child table). # SELECT rowid FROM track WHERE trackartist = ? where ? in the above is # replaced with the value of the artistid column of the record being # deleted from the artist table (recall that the trackartist column is # the child key and the artistid column is the parent key).
R-47936-10044-12721-09990-49763-27309-53307-48514 tcl slt th3 src
Or, more generally:
SELECT rowid FROM <child-table> WHERE <child-key> = :parent_key_value
tcl/e_fkey.test:1034 th3/req1/foreignkeys10.test:47
/* IMP: R-47936-10044 */
# EVIDENCE-OF: R-47936-10044 Or, more generally: SELECT rowid FROM # <child-table> WHERE <child-key> = :parent_key_value
R-23302-30956-02464-62581-38265-62787-52147-51200 tcl slt th3 src
If this SELECT returns any rows at all, then SQLite concludes that deleting the row from the parent table would violate the foreign key constraint and returns an error.
tcl/e_fkey.test:972 th3/req1/foreignkeys10.test:65
/* IMP: R-23302-30956 */
# EVIDENCE-OF: R-23302-30956 If this SELECT returns any rows at all, # then SQLite concludes that deleting the row from the parent table # would violate the foreign key constraint and returns an error.
R-61616-46700-48571-17878-11289-09346-32706-45031 tcl slt th3 src
Similar queries may be run if the content of the parent key is modified or a new row is inserted into the parent table.
tcl/e_fkey.test:1050 th3/req1/foreignkeys10.test:87
/* IMP: R-61616-46700 */
# EVIDENCE-OF: R-61616-46700 Similar queries may be run if the content # of the parent key is modified or a new row is inserted into the parent # table.
R-15741-50893-04622-59701-05174-07929-61978-12539 tcl slt th3 src
The child key index does not have to be (and usually will not be) a UNIQUE index.
tcl/e_fkey.test:937 th3/req1/foreignkeys09.test:11
/* IMP: R-15741-50893 */
# EVIDENCE-OF: R-15741-50893 The child key index does not have to be # (and usually will not be) a UNIQUE index.
R-14553-34013-61751-37329-34569-35054-62588-04416 tcl slt th3 src
the complete database schema for efficient implementation of the foreign key constraint might be:
CREATE TABLE artist( artistid INTEGER PRIMARY KEY, artistname TEXT ); CREATE TABLE track( trackid INTEGER, trackname TEXT, trackartist INTEGER REFERENCES artist ); CREATE INDEX trackindex ON track(trackartist);
tcl/e_fkey.test:1093 th3/req1/foreignkeys09.test:14
/* IMP: R-14553-34013 */
# EVIDENCE-OF: R-14553-34013 the complete database schema for efficient # implementation of the foreign key constraint might be: CREATE TABLE # artist( artistid INTEGER PRIMARY KEY, artistname TEXT ); CREATE TABLE # track( trackid INTEGER, trackname TEXT, trackartist INTEGER REFERENCES # artist ); CREATE INDEX trackindex ON track(trackartist);
R-43879-08025-52526-08970-15750-21422-30684-37873 tcl slt th3 src
Attaching a "REFERENCES <parent-table>" clause to a column definition creates a foreign key constraint that maps the column to the primary key of <parent-table>.
tcl/e_fkey.test:901 th3/req1/foreignkeys09.test:32
/* IMP: R-43879-08025 */
# EVIDENCE-OF: R-43879-08025 Attaching a "REFERENCES # <parent-table>" clause to a column definition creates a foreign # key constraint that maps the column to the primary key of # <parent-table>.
R-24676-09859-25258-06679-18327-03281-24955-00264 tcl slt th3 src
For example, consider the following database schema:
CREATE TABLE album( albumartist TEXT, albumname TEXT, albumcover BINARY, PRIMARY KEY(albumartist, albumname) ); CREATE TABLE song( songid INTEGER, songartist TEXT, songalbum TEXT, songname TEXT, FOREIGN KEY(songartist, songalbum) REFERENCES album(albumartist, albumname) );
In this system, each entry in the song table is required to map to an entry in the album table with the same combination of artist and album.
tcl/e_fkey.test:1184 th3/req1/foreignkeys11.test:11
/* IMP: R-24676-09859 */
# EVIDENCE-OF: R-24676-09859 For example, consider the following # database schema: CREATE TABLE album( albumartist TEXT, albumname TEXT, # albumcover BINARY, PRIMARY KEY(albumartist, albumname) ); CREATE TABLE # song( songid INTEGER, songartist TEXT, songalbum TEXT, songname TEXT, # FOREIGN KEY(songartist, songalbum) REFERENCES album(albumartist, # albumname) ); In this system, each entry in the song table is required # to map to an entry in the album table with the same combination of # artist and album.
R-41062-34431-24503-40012-23472-27163-07838-01416 tcl slt th3 src
Parent and child keys must have the same cardinality.
tcl/e_fkey.test:1138 th3/req1/foreignkeys11.test:70
/* IMP: R-41062-34431 */
# EVIDENCE-OF: R-41062-34431 Parent and child keys must have the same # cardinality.
R-33626-48418-46855-58211-38849-29467-54588-01790 tcl slt th3 src
In SQLite, if any of the child key columns (in this case songartist and songalbum) are NULL, then there is no requirement for a corresponding row in the parent table.
tcl/e_fkey.test:1223 th3/req1/foreignkeys11.test:53
/* IMP: R-33626-48418 */
# EVIDENCE-OF: R-33626-48418 In SQLite, if any of the child key columns # (in this case songartist and songalbum) are NULL, then there is no # requirement for a corresponding row in the parent table.
R-30323-21917-40561-21411-57538-63013-10240-64875 tcl slt th3 src
Each foreign key constraint in SQLite is classified as either immediate or deferred.
src/build.c:3728 src/fkey.c:1460 src/sqliteInt.h:2484 tcl/e_fkey.test:1388 th3/req1/foreignkeys12.test:12
/* IMP: R-30323-21917 */
# EVIDENCE-OF: R-30323-21917 Each foreign key constraint in SQLite is # classified as either immediate or deferred.
R-35290-16460-32571-10958-08768-45451-01146-58774 tcl slt th3 src
Foreign key constraints are immediate by default.
tcl/e_fkey.test:1385 th3/req1/foreignkeys12.test:15
/* IMP: R-35290-16460 */
# EVIDENCE-OF: R-35290-16460 Foreign key constraints are immediate by # default.
R-09323-30470-62004-36090-30809-61331-17692-32313 tcl slt th3 src
If a statement modifies the contents of the database so that an immediate foreign key constraint is in violation at the conclusion the statement, an exception is thrown and the effects of the statement are reverted.
tcl/e_fkey.test:1244 th3/req1/foreignkeys12.test:63
/* IMP: R-09323-30470 */
# EVIDENCE-OF: R-09323-30470 If a statement modifies the contents of the # database so that an immediate foreign key constraint is in violation # at the conclusion the statement, an exception is thrown and the # effects of the statement are reverted.
R-49178-21358-58489-31319-06651-33455-27209-45773 tcl slt th3 src
By contrast, if a statement modifies the contents of the database such that a deferred foreign key constraint is violated, the violation is not reported immediately.
tcl/e_fkey.test:1299 th3/req1/foreignkeys12.test:79
/* IMP: R-49178-21358 */
# EVIDENCE-OF: R-49178-21358 By contrast, if a statement modifies the # contents of the database such that a deferred foreign key constraint # is violated, the violation is not reported immediately.
R-39692-12488-54491-44352-04912-13609-39585-46004 tcl slt th3 src
Deferred foreign key constraints are not checked until the transaction tries to COMMIT.
tcl/e_fkey.test:1303 th3/req1/foreignkeys12.test:87 th3/req1/foreignkeys14.test:33
/* IMP: R-39692-12488 */
# EVIDENCE-OF: R-39692-12488 Deferred foreign key constraints are not # checked until the transaction tries to COMMIT.
R-55147-47664-01653-03142-36497-30903-54815-06427 tcl slt th3 src
For as long as the user has an open transaction, the database is allowed to exist in a state that violates any number of deferred foreign key constraints.
tcl/e_fkey.test:1306 th3/req1/foreignkeys12.test:90 th3/req1/foreignkeys14.test:36
/* IMP: R-55147-47664 */
# EVIDENCE-OF: R-55147-47664 For as long as the user has an open # transaction, the database is allowed to exist in a state that violates # any number of deferred foreign key constraints.
R-29604-30395-11418-33165-02079-38209-02467-57208 tcl slt th3 src
However, COMMIT will fail as long as foreign key constraints remain in violation.
tcl/e_fkey.test:1310 th3/req1/foreignkeys12.test:94 th3/req1/foreignkeys14.test:40
/* IMP: R-29604-30395 */
# EVIDENCE-OF: R-29604-30395 However, COMMIT will fail as long as # foreign key constraints remain in violation.
R-56844-61705-36939-38835-21077-60167-01566-10120 tcl slt th3 src
If the current statement is not inside an explicit transaction (a BEGIN/COMMIT/ROLLBACK block), then an implicit transaction is committed as soon as the statement has finished executing. In this case deferred constraints behave the same as immediate constraints.
tcl/e_fkey.test:1337 th3/req1/foreignkeys12.test:105
/* IMP: R-56844-61705 */
# EVIDENCE-OF: R-56844-61705 If the current statement is not inside an # explicit transaction (a BEGIN/COMMIT/ROLLBACK block), then an implicit # transaction is committed as soon as the statement has finished # executing. In this case deferred constraints behave the same as # immediate constraints.
R-12782-61841-54063-57500-26369-54791-20214-34360 tcl slt th3 src
To mark a foreign key constraint as deferred, its declaration must include the following clause:
DEFERRABLE INITIALLY DEFERRED -- A deferred foreign key constraint
tcl/e_fkey.test:1364 th3/req1/foreignkeys12.test:17
/* IMP: R-12782-61841 */
# EVIDENCE-OF: R-12782-61841 To mark a foreign key constraint as # deferred, its declaration must include the following clause: # DEFERRABLE INITIALLY DEFERRED -- A deferred foreign key constraint
R-09005-28791-60027-45340-35703-17892-19441-18649 tcl slt th3 src
Replacing the phrase above with any of the following creates an immediate foreign key constraint.
NOT DEFERRABLE INITIALLY DEFERRED -- An immediate foreign key constraint NOT DEFERRABLE INITIALLY IMMEDIATE -- An immediate foreign key constraint NOT DEFERRABLE -- An immediate foreign key constraint DEFERRABLE INITIALLY IMMEDIATE -- An immediate foreign key constraint DEFERRABLE -- An immediate foreign key constraint
tcl/e_fkey.test:1371 th3/req1/foreignkeys12.test:21
/* IMP: R-09005-28791 */
# EVIDENCE-OF: R-09005-28791 Replacing the phrase above with any of the # following creates an immediate foreign key constraint. NOT DEFERRABLE # INITIALLY DEFERRED -- An immediate foreign key constraint NOT # DEFERRABLE INITIALLY IMMEDIATE -- An immediate foreign key constraint # NOT DEFERRABLE -- An immediate foreign key constraint DEFERRABLE # INITIALLY IMMEDIATE -- An immediate foreign key constraint DEFERRABLE # -- An immediate foreign key constraint
R-24499-57071-23351-26477-16690-35822-52475-36418 tcl slt th3 src
The following example illustrates the effect of using a deferred foreign key constraint.
-- Database schema. Both tables are initially empty. CREATE TABLE artist( artistid INTEGER PRIMARY KEY, artistname TEXT ); CREATE TABLE track( trackid INTEGER, trackname TEXT, trackartist INTEGER REFERENCES artist(artistid) DEFERRABLE INITIALLY DEFERRED ); sqlite3> -- If the foreign key constraint were immediate, this INSERT would sqlite3> -- cause an error (since as there is no row in table artist with sqlite3> -- artistid=5). But as the constraint is deferred and there is an sqlite3> -- open transaction, no error occurs. sqlite3> BEGIN; sqlite3> INSERT INTO track VALUES(1, 'White Christmas', 5); sqlite3> -- The following COMMIT fails, as the database is in a state that sqlite3> -- does not satisfy the deferred foreign key constraint. The sqlite3> -- transaction remains open. sqlite3> COMMIT; SQL error: foreign key constraint failed sqlite3> -- After inserting a row into the artist table with artistid=5, the sqlite3> -- deferred foreign key constraint is satisfied. It is then possible sqlite3> -- to commit the transaction without error. sqlite3> INSERT INTO artist VALUES(5, 'Bing Crosby'); sqlite3> COMMIT;
tcl/e_fkey.test:1486 th3/req1/foreignkeys13.test:11
/* IMP: R-24499-57071 */
# EVIDENCE-OF: R-24499-57071 The following example illustrates the # effect of using a deferred foreign key constraint. -- Database schema. # Both tables are initially empty. CREATE TABLE artist( artistid INTEGER # PRIMARY KEY, artistname TEXT ); CREATE TABLE track( trackid INTEGER, # trackname TEXT, trackartist INTEGER REFERENCES artist(artistid) # DEFERRABLE INITIALLY DEFERRED ); sqlite3> -- If the foreign key # constraint were immediate, this INSERT would sqlite3> -- cause an # error (since as there is no row in table artist with sqlite3> -- # artistid=5). But as the constraint is deferred and there is an # sqlite3> -- open transaction, no error occurs. sqlite3> BEGIN; # sqlite3> INSERT INTO track VALUES(1, 'White Christmas', 5); # sqlite3> -- The following COMMIT fails, as the database is in a # state that sqlite3> -- does not satisfy the deferred foreign key # constraint. The sqlite3> -- transaction remains open. sqlite3> # COMMIT; SQL error: foreign key constraint failed sqlite3> -- After # inserting a row into the artist table with artistid=5, the sqlite3> # -- deferred foreign key constraint is satisfied. It is then possible # sqlite3> -- to commit the transaction without error. sqlite3> # INSERT INTO artist VALUES(5, 'Bing Crosby'); sqlite3> COMMIT;
R-07223-48323-28604-04641-30689-62184-47326-29698 tcl slt th3 src
A nested savepoint transaction may be RELEASEd while the database is in a state that does not satisfy a deferred foreign key constraint.
tcl/e_fkey.test:1523 th3/req1/foreignkeys15.test:32
/* IMP: R-07223-48323 */
# EVIDENCE-OF: R-07223-48323 A nested savepoint transaction may be # RELEASEd while the database is in a state that does not satisfy a # deferred foreign key constraint.
R-44295-13823-09058-27289-44091-57467-52153-35683 tcl slt th3 src
A transaction savepoint (a non-nested savepoint that was opened while there was not currently an open transaction), on the other hand, is subject to the same restrictions as a COMMIT - attempting to RELEASE it while the database is in such a state will fail.
tcl/e_fkey.test:1562 th3/req1/foreignkeys15.test:47
/* IMP: R-44295-13823 */
# EVIDENCE-OF: R-44295-13823 A transaction savepoint (a non-nested # savepoint that was opened while there was not currently an open # transaction), on the other hand, is subject to the same restrictions # as a COMMIT - attempting to RELEASE it while the database is in such a # state will fail.
R-37736-42616-04169-53390-00856-45033-53695-63004 tcl slt th3 src
If a COMMIT statement (or the RELEASE of a transaction SAVEPOINT) fails because the database is currently in a state that violates a deferred foreign key constraint and there are currently nested savepoints, the nested savepoints remain open.
tcl/e_fkey.test:1604 th3/req1/foreignkeys15.test:64
/* IMP: R-37736-42616 */
# EVIDENCE-OF: R-37736-42616 If a COMMIT statement (or the RELEASE of a # transaction SAVEPOINT) fails because the database is currently in a # state that violates a deferred foreign key constraint and there are # currently nested savepoints, the nested savepoints remain open.
R-48270-44282-22791-02682-41212-30485-35514-10094 tcl slt th3 src
Foreign key ON DELETE and ON UPDATE clauses are used to configure actions that take place when deleting rows from the parent table (ON DELETE), or modifying the parent key values of existing rows (ON UPDATE).
tcl/e_fkey.test:1668 th3/req1/pragma02.test:12
/* IMP: R-48270-44282 */
# EVIDENCE-OF: R-48270-44282 Foreign key ON DELETE and ON UPDATE clauses # are used to configure actions that take place when deleting rows from # the parent table (ON DELETE), or modifying the parent key values of # existing rows (ON UPDATE).
R-48124-63225-09560-63618-32598-12840-01456-15525 tcl slt th3 src
A single foreign key constraint may have different actions configured for ON DELETE and ON UPDATE.
tcl/e_fkey.test:1676 th3/req1/pragma02.test:46 th3/req1/pragma02.test:77
/* IMP: R-48124-63225 */
# EVIDENCE-OF: R-48124-63225 A single foreign key constraint may have # different actions configured for ON DELETE and ON UPDATE.
R-33326-45252-38720-14593-54555-59144-23018-05599 tcl slt th3 src
The ON DELETE and ON UPDATE action associated with each foreign key in an SQLite database is one of "NO ACTION", "RESTRICT", "SET NULL", "SET DEFAULT" or "CASCADE".
src/parse.y:416 src/parse.y:417 src/parse.y:418 src/parse.y:419 src/parse.y:420 tcl/e_fkey.test:1721 th3/req1/foreignkeys16.test:12
/* IMP: R-33326-45252 */
# EVIDENCE-OF: R-33326-45252 The ON DELETE and ON UPDATE action # associated with each foreign key in an SQLite database is one of "NO # ACTION", "RESTRICT", "SET NULL", "SET DEFAULT" or "CASCADE".
R-19803-45884-64369-17915-53923-43638-05068-02663 tcl slt th3 src
If an action is not explicitly specified, it defaults to "NO ACTION".
src/parse.y:408 tcl/e_fkey.test:1727 th3/req1/foreignkeys16.test:199 th3/req1/foreignkeys16.test:39
/* IMP: R-19803-45884 */
# EVIDENCE-OF: R-19803-45884 If an action is not explicitly specified, # it defaults to "NO ACTION".
R-19971-54976-54556-37696-16686-39038-59563-20085 tcl slt th3 src
Configuring "NO ACTION" means just that: when a parent key is modified or deleted from the database, no special action is taken.
tcl/e_fkey.test:1772 th3/req1/foreignkeys16.test:18 th3/req1/foreignkeys16.test:184
/* IMP: R-19971-54976 */
# EVIDENCE-OF: R-19971-54976 Configuring "NO ACTION" means just that: # when a parent key is modified or deleted from the database, no special # action is taken.
R-04272-38653-14303-01704-38451-58113-36784-29823 tcl slt th3 src
The "RESTRICT" action means that the application is prohibited from deleting (for ON DELETE RESTRICT) or modifying (for ON UPDATE RESTRICT) a parent key when there exists one or more child keys mapped to it.
tcl/e_fkey.test:1812 th3/req1/foreignkeys16.test:221 th3/req1/foreignkeys16.test:54
/* IMP: R-04272-38653 */
# EVIDENCE-OF: R-04272-38653 The "RESTRICT" action means that the # application is prohibited from deleting (for ON DELETE RESTRICT) or # modifying (for ON UPDATE RESTRICT) a parent key when there exists one # or more child keys mapped to it.
R-37997-42187-51725-59091-37072-50205-56712-26602 tcl slt th3 src
The difference between the effect of a RESTRICT action and normal foreign key constraint enforcement is that the RESTRICT action processing happens as soon as the field is updated - not at the end of the current statement as it would with an immediate constraint, or at the end of the current transaction as it would with a deferred constraint.
tcl/e_fkey.test:1850 th3/req1/foreignkeys16.test:214 th3/req1/foreignkeys16.test:238 th3/req1/foreignkeys16.test:71
/* IMP: R-37997-42187 */
# EVIDENCE-OF: R-37997-42187 The difference between the effect of a # RESTRICT action and normal foreign key constraint enforcement is that # the RESTRICT action processing happens as soon as the field is updated # - not at the end of the current statement as it would with an # immediate constraint, or at the end of the current transaction as it # would with a deferred constraint.
R-24179-60523-60164-40067-19292-39680-45687-45747 tcl slt th3 src
Even if the foreign key constraint it is attached to is deferred, configuring a RESTRICT action causes SQLite to return an error immediately if a parent key with dependent child keys is deleted or modified.
tcl/e_fkey.test:1939 th3/req1/foreignkeys16.test:100 th3/req1/foreignkeys16.test:253
/* IMP: R-24179-60523 */
# EVIDENCE-OF: R-24179-60523 Even if the foreign key constraint it is # attached to is deferred, configuring a RESTRICT action causes SQLite # to return an error immediately if a parent key with dependent child # keys is deleted or modified.
R-03353-05327-21191-28288-58549-30161-65035-16573 tcl slt th3 src
If the configured action is "SET NULL", then when a parent key is deleted (for ON DELETE SET NULL) or modified (for ON UPDATE SET NULL), the child key columns of all rows in the child table that mapped to the parent key are set to contain SQL NULL values.
tcl/e_fkey.test:2015 th3/req1/foreignkeys16.test:125 th3/req1/foreignkeys16.test:275
/* IMP: R-03353-05327 */
# EVIDENCE-OF: R-03353-05327 If the configured action is "SET NULL", # then when a parent key is deleted (for ON DELETE SET NULL) or modified # (for ON UPDATE SET NULL), the child key columns of all rows in the # child table that mapped to the parent key are set to contain SQL NULL # values.
R-55814-22637-16882-39129-49686-50158-19394-50709 tcl slt th3 src
The "SET DEFAULT" actions are similar to "SET NULL", except that each of the child key columns is set to contain the column's default value instead of NULL.
tcl/e_fkey.test:2058 th3/req1/foreignkeys16.test:142 th3/req1/foreignkeys16.test:292
/* IMP: R-55814-22637 */
# EVIDENCE-OF: R-55814-22637 The "SET DEFAULT" actions are similar to # "SET NULL", except that each of the child key columns is set to # contain the column's default value instead of NULL.
R-61376-57267-60176-57380-17573-65142-26150-27865 tcl slt th3 src
A "CASCADE" action propagates the delete or update operation on the parent key to each dependent child key.
tcl/e_fkey.test:2100 tcl/e_fkey.test:2145 th3/req1/foreignkeys16.test:159 th3/req1/foreignkeys16.test:309
/* IMP: R-61376-57267 */
# EVIDENCE-OF: R-61376-57267 A "CASCADE" action propagates the delete or # update operation on the parent key to each dependent child key.
R-61809-62207-01008-46404-05799-53014-10578-37094 tcl slt th3 src
For an "ON DELETE CASCADE" action, this means that each row in the child table that was associated with the deleted parent row is also deleted.
tcl/e_fkey.test:2103 th3/req1/foreignkeys16.test:162
/* IMP: R-61809-62207 */
# EVIDENCE-OF: R-61809-62207 For an "ON DELETE CASCADE" action, this # means that each row in the child table that was associated with the # deleted parent row is also deleted.
R-13877-64542-39833-15687-62784-10394-38782-49019 tcl slt th3 src
For an "ON UPDATE CASCADE" action, it means that the values stored in each dependent child key are modified to match the new parent key values.
tcl/e_fkey.test:2141 th3/req1/foreignkeys16.test:312
/* IMP: R-13877-64542 */
# EVIDENCE-OF: R-13877-64542 For an "ON UPDATE CASCADE" action, it means # that the values stored in each dependent child key are modified to # match the new parent key values.
R-65058-57158-61886-52055-64360-05204-52569-52918 tcl slt th3 src
For example, adding an "ON UPDATE CASCADE" clause to the foreign key as shown below enhances the example schema from section 1 to allow the user to update the artistid (the parent key of the foreign key constraint) column without breaking referential integrity:
-- Database schema CREATE TABLE artist( artistid INTEGER PRIMARY KEY, artistname TEXT ); CREATE TABLE track( trackid INTEGER, trackname TEXT, trackartist INTEGER REFERENCES artist(artistid) ON UPDATE CASCADE ); sqlite> SELECT * FROM artist; artistid artistname -------- ----------------- 1 Dean Martin 2 Frank Sinatra sqlite> SELECT * FROM track; trackid trackname trackartist ------- ----------------- ----------- 11 That's Amore 1 12 Christmas Blues 1 13 My Way 2 sqlite> -- Update the artistid column of the artist record for "Dean Martin". sqlite> -- Normally, this would raise a constraint, as it would orphan the two sqlite> -- dependent records in the track table. However, the ON UPDATE CASCADE clause sqlite> -- attached to the foreign key definition causes the update to "cascade" sqlite> -- to the child table, preventing the foreign key constraint violation. sqlite> UPDATE artist SET artistid = 100 WHERE artistname = 'Dean Martin'; sqlite> SELECT * FROM artist; artistid artistname -------- ----------------- 2 Frank Sinatra 100 Dean Martin sqlite> SELECT * FROM track; trackid trackname trackartist ------- ----------------- ----------- 11 That's Amore 100 12 Christmas Blues 100 13 My Way 2
tcl/e_fkey.test:2185 th3/req1/foreignkeys17.test:11
/* IMP: R-65058-57158 */
# EVIDENCE-OF: R-65058-57158 For example, adding an "ON UPDATE CASCADE" # clause to the foreign key as shown below enhances the example schema # from section 1 to allow the user to update the artistid (the parent # key of the foreign key constraint) column without breaking referential # integrity: -- Database schema CREATE TABLE artist( artistid INTEGER # PRIMARY KEY, artistname TEXT ); CREATE TABLE track( trackid INTEGER, # trackname TEXT, trackartist INTEGER REFERENCES artist(artistid) ON # UPDATE CASCADE ); sqlite> SELECT * FROM artist; artistid artistname # -------- ----------------- 1 Dean Martin 2 Frank Sinatra sqlite> # SELECT * FROM track; trackid trackname trackartist ------- # ----------------- ----------- 11 That's Amore 1 12 Christmas Blues 1 # 13 My Way 2 sqlite> -- Update the artistid column of the artist # record for "Dean Martin". sqlite> -- Normally, this would raise a # constraint, as it would orphan the two sqlite> -- dependent records # in the track table. However, the ON UPDATE CASCADE clause sqlite> # -- attached to the foreign key definition causes the update to # "cascade" sqlite> -- to the child table, preventing the foreign key # constraint violation. sqlite> UPDATE artist SET artistid = 100 # WHERE artistname = 'Dean Martin'; sqlite> SELECT * FROM artist; # artistid artistname -------- ----------------- 2 Frank Sinatra 100 # Dean Martin sqlite> SELECT * FROM track; trackid trackname # trackartist ------- ----------------- ----------- 11 That's Amore 100 # 12 Christmas Blues 100 13 My Way 2
R-53968-51642-29002-32833-59790-62444-61146-02233 tcl slt th3 src
Configuring an ON UPDATE or ON DELETE action does not mean that the foreign key constraint does not need to be satisfied.
tcl/e_fkey.test:2227 th3/req1/foreignkeys18.test:12
/* IMP: R-53968-51642 */
# EVIDENCE-OF: R-53968-51642 Configuring an ON UPDATE or ON DELETE # action does not mean that the foreign key constraint does not need to # be satisfied.
R-28220-46694-36270-42674-38857-47778-22952-56853 tcl slt th3 src
For example, if an "ON DELETE SET DEFAULT" action is configured, but there is no row in the parent table that corresponds to the default values of the child key columns, deleting a parent key while dependent child keys exist still causes a foreign key violation.
tcl/e_fkey.test:2271 th3/req1/foreignkeys18.test:15
/* IMP: R-28220-46694 */
# EVIDENCE-OF: R-28220-46694 For example, if an "ON DELETE SET DEFAULT" # action is configured, but there is no row in the parent table that # corresponds to the default values of the child key columns, deleting a # parent key while dependent child keys exist still causes a foreign key # violation.
R-11856-19836-24274-28109-29706-17487-59516-28752 tcl slt th3 src
For example:
-- Database schema CREATE TABLE artist( artistid INTEGER PRIMARY KEY, artistname TEXT ); CREATE TABLE track( trackid INTEGER, trackname TEXT, trackartist INTEGER DEFAULT 0 REFERENCES artist(artistid) ON DELETE SET DEFAULT ); sqlite> SELECT * FROM artist; artistid artistname -------- ----------------- 3 Sammy Davis Jr. sqlite> SELECT * FROM track; trackid trackname trackartist ------- ----------------- ----------- 14 Mr. Bojangles 3 sqlite> -- Deleting the row from the parent table causes the child key sqlite> -- value of the dependent row to be set to integer value 0. However, this sqlite> -- value does not correspond to any row in the parent table. Therefore sqlite> -- the foreign key constraint is violated and an is exception thrown. sqlite> DELETE FROM artist WHERE artistname = 'Sammy Davis Jr.'; SQL error: foreign key constraint failed sqlite> -- This time, the value 0 does correspond to a parent table row. And sqlite> -- so the DELETE statement does not violate the foreign key constraint sqlite> -- and no exception is thrown. sqlite> INSERT INTO artist VALUES(0, 'Unknown Artist'); sqlite> DELETE FROM artist WHERE artistname = 'Sammy Davis Jr.'; sqlite> SELECT * FROM artist; artistid artistname -------- ----------------- 0 Unknown Artist sqlite> SELECT * FROM track; trackid trackname trackartist ------- ----------------- ----------- 14 Mr. Bojangles 0
tcl/e_fkey.test:2264 th3/req1/foreignkeys18.test:20
/* IMP: R-11856-19836 */
# EVIDENCE-OF: R-11856-19836 For example: -- Database schema CREATE # TABLE artist( artistid INTEGER PRIMARY KEY, artistname TEXT ); CREATE # TABLE track( trackid INTEGER, trackname TEXT, trackartist INTEGER # DEFAULT 0 REFERENCES artist(artistid) ON DELETE SET DEFAULT ); # sqlite> SELECT * FROM artist; artistid artistname -------- # ----------------- 3 Sammy Davis Jr. sqlite> SELECT * FROM track; # trackid trackname trackartist ------- ----------------- ----------- 14 # Mr. Bojangles 3 sqlite> -- Deleting the row from the parent table # causes the child key sqlite> -- value of the dependent row to be # set to integer value 0. However, this sqlite> -- value does not # correspond to any row in the parent table. Therefore sqlite> -- the # foreign key constraint is violated and an is exception thrown. # sqlite> DELETE FROM artist WHERE artistname = 'Sammy Davis Jr.'; # SQL error: foreign key constraint failed sqlite> -- This time, the # value 0 does correspond to a parent table row. And sqlite> -- so # the DELETE statement does not violate the foreign key constraint # sqlite> -- and no exception is thrown. sqlite> INSERT INTO # artist VALUES(0, 'Unknown Artist'); sqlite> DELETE FROM artist # WHERE artistname = 'Sammy Davis Jr.'; sqlite> SELECT * FROM artist; # artistid artistname -------- ----------------- 0 Unknown Artist # sqlite> SELECT * FROM track; trackid trackname trackartist ------- # ----------------- ----------- 14 Mr. Bojangles 0
R-09564-22170-27375-05763-54488-45369-57253-27733 tcl slt th3 src
Whenever a row in the parent table of a foreign key constraint is deleted, or when the values stored in the parent key column or columns are modified, the logical sequence of events is:
- Execute applicable BEFORE trigger programs,
- Check local (non foreign key) constraints,
- Update or delete the row in the parent table,
- Perform any required foreign key actions,
- Execute applicable AFTER trigger programs.
tcl/e_fkey.test:2310 th3/req1/foreignkeys19.test:12
/* IMP: R-09564-22170 */
# EVIDENCE-OF: R-09564-22170 Whenever a row in the parent table of a # foreign key constraint is deleted, or when the values stored in the # parent key column or columns are modified, the logical sequence of # events is: Execute applicable BEFORE trigger programs, Check local # (non foreign key) constraints, Update or delete the row in the parent # table, Perform any required foreign key actions, Execute applicable # AFTER trigger programs.
R-27383-10246-01655-25271-51755-59417-27078-62241 tcl slt th3 src
An ON UPDATE action is only taken if the values of the parent key are modified so that the new parent key values are not equal to the old.
tcl/e_fkey.test:2367 th3/req1/foreignkeys20.test:12
/* IMP: R-27383-10246 */
# EVIDENCE-OF: R-27383-10246 An ON UPDATE action is only taken if the # values of the parent key are modified so that the new parent key # values are not equal to the old.
R-35129-58141-36157-07998-30656-14308-25733-01656 tcl slt th3 src
For example:
-- Database schema CREATE TABLE parent(x PRIMARY KEY); CREATE TABLE child(y REFERENCES parent ON UPDATE SET NULL); sqlite> SELECT * FROM parent; x ---- key sqlite> SELECT * FROM child; y ---- key sqlite> -- Since the following UPDATE statement does not actually modify sqlite> -- the parent key value, the ON UPDATE action is not performed and sqlite> -- the child key value is not set to NULL. sqlite> UPDATE parent SET x = 'key'; sqlite> SELECT IFNULL(y, 'null') FROM child; y ---- key sqlite> -- This time, since the UPDATE statement does modify the parent key sqlite> -- value, the ON UPDATE action is performed and the child key is set sqlite> -- to NULL. sqlite> UPDATE parent SET x = 'key2'; sqlite> SELECT IFNULL(y, 'null') FROM child; y ---- null
tcl/e_fkey.test:2418 th3/req1/foreignkeys20.test:16
/* IMP: R-35129-58141 */
# EVIDENCE-OF: R-35129-58141 For example: -- Database schema CREATE # TABLE parent(x PRIMARY KEY); CREATE TABLE child(y REFERENCES parent ON # UPDATE SET NULL); sqlite> SELECT * FROM parent; x ---- key # sqlite> SELECT * FROM child; y ---- key sqlite> -- Since the # following UPDATE statement does not actually modify sqlite> -- the # parent key value, the ON UPDATE action is not performed and sqlite> # -- the child key value is not set to NULL. sqlite> UPDATE parent # SET x = 'key'; sqlite> SELECT IFNULL(y, 'null') FROM child; y ---- # key sqlite> -- This time, since the UPDATE statement does modify # the parent key sqlite> -- value, the ON UPDATE action is performed # and the child key is set sqlite> -- to NULL. sqlite> UPDATE # parent SET x = 'key2'; sqlite> SELECT IFNULL(y, 'null') FROM child; # y ---- null
R-08908-23439-37383-27763-09062-14229-58252-49666 tcl slt th3 src
A CREATE TABLE command operates the same whether or not foreign key constraints are enabled.
tcl/e_fkey.test:2471 th3/req1/foreignkeys21.test:12
/* IMP: R-08908-23439 */
# EVIDENCE-OF: R-08908-23439 A CREATE TABLE command operates the same # whether or not foreign key constraints are enabled.
R-36018-21755-34988-08386-62029-36954-65009-29361 tcl slt th3 src
The parent key definitions of foreign key constraints are not checked when a table is created.
tcl/e_fkey.test:2454 th3/req1/foreignkeys21.test:15
/* IMP: R-36018-21755 */
# EVIDENCE-OF: R-36018-21755 The parent key definitions of foreign key # constraints are not checked when a table is created.
R-25384-39337-58415-17102-37697-27977-14467-00416 tcl slt th3 src
There is nothing stopping the user from creating a foreign key definition that refers to a parent table that does not exist, or to parent key columns that do not exist or are not collectively bound by a PRIMARY KEY or UNIQUE constraint.
tcl/e_fkey.test:2457 th3/req1/foreignkeys21.test:18
/* IMP: R-25384-39337 */
# EVIDENCE-OF: R-25384-39337 There is nothing stopping the user from # creating a foreign key definition that refers to a parent table that # does not exist, or to parent key columns that do not exist or are not # collectively bound by a PRIMARY KEY or UNIQUE constraint.
R-47952-62498-54054-51429-18050-07399-51898-49231 tcl slt th3 src
It is not possible to use the "ALTER TABLE ... ADD COLUMN" syntax to add a column that includes a REFERENCES clause, unless the default value of the new column is NULL. Attempting to do so returns an error.
tcl/e_fkey.test:2501 th3/req1/foreignkeys21.test:47
/* IMP: R-47952-62498 */
# EVIDENCE-OF: R-47952-62498 It is not possible to use the "ALTER TABLE # ... ADD COLUMN" syntax to add a column that includes a REFERENCES # clause, unless the default value of the new column is NULL. Attempting # to do so returns an error.
R-47080-02069-19289-28177-02416-33406-46082-01364 tcl slt th3 src
If an "ALTER TABLE ... RENAME TO" command is used to rename a table that is the parent table of one or more foreign key constraints, the definitions of the foreign key constraints are modified to refer to the parent table by its new name
tcl/e_fkey.test:2526 th3/req1/foreignkeys21.test:63
/* IMP: R-47080-02069 */
# EVIDENCE-OF: R-47080-02069 If an "ALTER TABLE ... RENAME TO" command # is used to rename a table that is the parent table of one or more # foreign key constraints, the definitions of the foreign key # constraints are modified to refer to the parent table by its new name
R-43040-62530-50072-37699-18765-48451-48404-22344 tcl slt th3 src
The text of the child CREATE TABLE statement or statements stored in the sqlite_schema table are modified to reflect the new parent table name.
tcl/e_fkey.test:2533 th3/req1/foreignkeys21.test:68
/* IMP: R-43040-62530 */
# EVIDENCE-OF: R-43040-62530 The text of the child CREATE TABLE # statement or statements stored in the sqlite_schema table are modified # to reflect the new parent table name.
R-14208-23986-02817-62350-58798-64603-05852-18001 tcl slt th3 src
If foreign key constraints are enabled when it is prepared, the DROP TABLE command performs an implicit DELETE to remove all rows from the table before dropping it.
tcl/e_fkey.test:2581 th3/req1/foreignkeys16.test:82 th3/req1/foreignkeys22.test:12
/* IMP: R-14208-23986 */
# EVIDENCE-OF: R-14208-23986 If foreign key constraints are enabled when # it is prepared, the DROP TABLE command performs an implicit DELETE to # remove all rows from the table before dropping it.
R-11078-03945-63030-33506-24033-34573-31697-17195 tcl slt th3 src
The implicit DELETE does not cause any SQL triggers to fire, but may invoke foreign key actions or constraint violations.
tcl/e_fkey.test:2585 th3/req1/foreignkeys16.test:86 th3/req1/foreignkeys22.test:16 th3/req1/foreignkeys22.test:45
/* IMP: R-11078-03945 */
# EVIDENCE-OF: R-11078-03945 The implicit DELETE does not cause any SQL # triggers to fire, but may invoke foreign key actions or constraint # violations.
R-32768-47925-14881-49153-08372-50935-16619-06911 tcl slt th3 src
If an immediate foreign key constraint is violated, the DROP TABLE statement fails and the table is not dropped.
tcl/e_fkey.test:2652 th3/req1/foreignkeys16.test:89 th3/req1/foreignkeys22.test:19
/* IMP: R-32768-47925 */
# EVIDENCE-OF: R-32768-47925 If an immediate foreign key constraint is # violated, the DROP TABLE statement fails and the table is not dropped.
R-05903-08460-38037-43122-07089-54739-62474-34030 tcl slt th3 src
If a deferred foreign key constraint is violated, then an error is reported when the user attempts to commit the transaction if the foreign key constraint violations still exist at that point.
tcl/e_fkey.test:2685 th3/req1/foreignkeys22.test:22
/* IMP: R-05903-08460 */
# EVIDENCE-OF: R-05903-08460 If a deferred foreign key constraint is # violated, then an error is reported when the user attempts to commit # the transaction if the foreign key constraint violations still exist # at that point.
R-57242-37005-56028-08872-40154-45403-20109-09312 tcl slt th3 src
Any "foreign key mismatch" errors encountered as part of an implicit DELETE are ignored.
tcl/e_fkey.test:2720 th3/req1/foreignkeys22.test:27
/* IMP: R-57242-37005 */
# EVIDENCE-OF: R-57242-37005 Any "foreign key mismatch" errors # encountered as part of an implicit DELETE are ignored.
R-54142-41346-32014-56293-25636-63110-30822-28140 tcl slt th3 src
The properties of the DROP TABLE and ALTER TABLE commands described above only apply if foreign keys are enabled.
tcl/e_fkey.test:2773 th3/req1/foreignkeys22.test:98
/* IMP: R-54142-41346 */
# EVIDENCE-OF: R-54142-41346 The properties of the DROP TABLE and ALTER # TABLE commands described above only apply if foreign keys are enabled.
R-24728-13230-17441-17828-27985-11598-34826-53003 tcl slt th3 src
SQLite parses MATCH clauses (i.e. does not report a syntax error if you specify one), but does not enforce them.
tcl/e_fkey.test:2848 th3/req1/foreignkeys23.test:13
/* IMP: R-24728-13230 */
# EVIDENCE-OF: R-24728-13230 SQLite parses MATCH clauses (i.e. does not # report a syntax error if you specify one), but does not enforce them.
R-24450-46174-44304-25763-63471-62798-12121-54973 tcl slt th3 src
All foreign key constraints in SQLite are handled as if MATCH SIMPLE were specified.
tcl/e_fkey.test:2851 th3/req1/foreignkeys23.test:16
/* IMP: R-24450-46174 */
# EVIDENCE-OF: R-24450-46174 All foreign key constraints in SQLite are # handled as if MATCH SIMPLE were specified.
R-21599-16038-23557-29825-04044-13537-53990-06867 tcl slt th3 src
In SQLite, a foreign key constraint is permanently marked as deferred or immediate when it is created.
tcl/e_fkey.test:2884 th3/req1/foreignkeys23.test:58
/* IMP: R-21599-16038 */
# EVIDENCE-OF: R-21599-16038 In SQLite, a foreign key constraint is # permanently marked as deferred or immediate when it is created.
R-42264-30503-59734-27182-09604-54439-24686-19729 tcl slt th3 src
The SQLITE_MAX_TRIGGER_DEPTH and SQLITE_LIMIT_TRIGGER_DEPTH settings determine the maximum allowable depth of trigger program recursion. For the purposes of these limits, foreign key actions are considered trigger programs.
tcl/e_fkey.test:2926 th3/req1/foreignkeys24.test:12
/* IMP: R-42264-30503 */
# EVIDENCE-OF: R-42264-30503 The SQLITE_MAX_TRIGGER_DEPTH and # SQLITE_LIMIT_TRIGGER_DEPTH settings determine the maximum allowable # depth of trigger program recursion. For the purposes of these limits, # foreign key actions are considered trigger programs.
R-44355-00270-30749-42094-52510-11222-59749-40119 tcl slt th3 src
The PRAGMA recursive_triggers setting does not affect the operation of foreign key actions.
tcl/e_fkey.test:3018 th3/req1/foreignkeys24.test:57
/* IMP: R-44355-00270 */
# EVIDENCE-OF: R-44355-00270 The PRAGMA recursive_triggers setting does # not affect the operation of foreign key actions.