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gh-108364: In sqlite3, disable foreign keys before dumping SQL schema (#113957)

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sqlite3.Connection.iterdump now ensures that foreign key support is
disabled before dumping the database schema, if there is any foreign key
violation.

Co-authored-by: Erlend E. Aasland <erlend@python.org>
This commit is contained in:
Mariusz Felisiak 2024-01-12 10:50:37 +01:00 • committed by GitHub
parent fcb4c8d31a
commit de777e490f
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3 changed files with 18 additions and 3 deletions
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4
Lib/sqlite3/dump.py
View file

@ -26,6 +26,10 @@ def _iterdump(connection):
writeable_schema = False
cu = connection.cursor()
# Disable foreign key constraints, if there is any foreign key violation.
violations = cu.execute("PRAGMA foreign_key_check").fetchall()
if violations:
yield('PRAGMA foreign_keys=OFF;')
yield('BEGIN TRANSACTION;')
# sqlite_master table contains the SQL CREATE statements for the database.

14
Lib/test/test_sqlite3/test_dump.py
View file

@ -20,7 +20,8 @@ def test_table_dump(self):
,
"CREATE TABLE t1(id integer primary key, s1 text, " \
"t1_i1 integer not null, i2 integer, unique (s1), " \
"constraint t1_idx1 unique (i2));"
"constraint t1_idx1 unique (i2), " \
"constraint t1_i1_idx1 unique (t1_i1));"
,
"INSERT INTO \"t1\" VALUES(1,'foo',10,20);"
,
@ -30,6 +31,9 @@ def test_table_dump(self):
"t2_i2 integer, primary key (id)," \
"foreign key(t2_i1) references t1(t1_i1));"
,
# Foreign key violation.
"INSERT INTO \"t2\" VALUES(1,2,3);"
,
"CREATE TRIGGER trigger_1 update of t1_i1 on t1 " \
"begin " \
"update t2 set t2_i1 = new.t1_i1 where t2_i1 = old.t1_i1; " \
@ -41,8 +45,12 @@ def test_table_dump(self):
[self.cu.execute(s) for s in expected_sqls]
i = self.cx.iterdump()
actual_sqls = [s for s in i]
expected_sqls = ['BEGIN TRANSACTION;'] + expected_sqls + \
['COMMIT;']
expected_sqls = [
"PRAGMA foreign_keys=OFF;",
"BEGIN TRANSACTION;",
*expected_sqls,
"COMMIT;",
]
[self.assertEqual(expected_sqls[i], actual_sqls[i])
for i in range(len(expected_sqls))]

3
Misc/NEWS.d/next/Library/2024-01-11-22-22-51.gh-issue-108364.QH7C-1.rst Normal file
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@ -0,0 +1,3 @@
:meth:`sqlite3.Connection.iterdump` now ensures that foreign key support is
disabled before dumping the database schema, if there is any foreign key
violation. Patch by Erlend E. Aasland and Mariusz Felisiak.