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# Mimic the sqlite3 console shell's .dump command
# Author: Paul Kippes <kippesp@gmail.com>
# Every identifier in sql is quoted based on a comment in sqlite
# documentation "SQLite adds new keywords from time to time when it
# takes on new features. So to prevent your code from being broken by
# future enhancements, you should normally quote any identifier that
# is an English language word, even if you do not have to."
def _iterdump(connection):
"""
Returns an iterator to the dump of the database in an SQL text format.
Used to produce an SQL dump of the database. Useful to save an in-memory
database for later restoration. This function should not be called
directly but instead called from the Connection method, iterdump().
"""
writeable_schema = False
cu = connection.cursor()
cu.row_factory = None # Make sure we get predictable results.
yield('BEGIN TRANSACTION;')
# sqlite_master table contains the SQL CREATE statements for the database.
q = """
SELECT "name", "type", "sql"
FROM "sqlite_master"
WHERE "sql" NOT NULL AND
"type" == 'table'
ORDER BY "name"
"""
schema_res = cu.execute(q)
sqlite_sequence = []
for table_name, type, sql in schema_res.fetchall():
if table_name == 'sqlite_sequence':
rows = cu.execute('SELECT * FROM "sqlite_sequence";').fetchall()
sqlite_sequence = ['DELETE FROM "sqlite_sequence"']
sqlite_sequence += [
f'INSERT INTO "sqlite_sequence" VALUES(\'{row[0]}\',{row[1]})'
for row in rows
]
continue
elif table_name == 'sqlite_stat1':
yield('ANALYZE "sqlite_master";')
elif table_name.startswith('sqlite_'):
continue
elif sql.startswith('CREATE VIRTUAL TABLE'):
if not writeable_schema:
writeable_schema = True
yield('PRAGMA writable_schema=ON;')
yield("INSERT INTO sqlite_master(type,name,tbl_name,rootpage,sql)"
"VALUES('table','{0}','{0}',0,'{1}');".format(
table_name.replace("'", "''"),
sql.replace("'", "''"),
))
else:
yield('{0};'.format(sql))
# Build the insert statement for each row of the current table
table_name_ident = table_name.replace('"', '""')
res = cu.execute('PRAGMA table_info("{0}")'.format(table_name_ident))
column_names = [str(table_info[1]) for table_info in res.fetchall()]
q = """SELECT 'INSERT INTO "{0}" VALUES({1})' FROM "{0}";""".format(
table_name_ident,
",".join("""'||quote("{0}")||'""".format(col.replace('"', '""')) for col in column_names))
query_res = cu.execute(q)
for row in query_res:
yield("{0};".format(row[0]))
# Now when the type is 'index', 'trigger', or 'view'
q = """
SELECT "name", "type", "sql"
FROM "sqlite_master"
WHERE "sql" NOT NULL AND
"type" IN ('index', 'trigger', 'view')
"""
schema_res = cu.execute(q)
for name, type, sql in schema_res.fetchall():
yield('{0};'.format(sql))
if writeable_schema:
yield('PRAGMA writable_schema=OFF;')
# gh-79009: Yield statements concerning the sqlite_sequence table at the
# end of the transaction.
for row in sqlite_sequence:
yield('{0};'.format(row))
yield('COMMIT;')
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