1  # Mimic the sqlite3 console shell's .dump command
       2  # Author: Paul Kippes <kippesp@gmail.com>
       3  
       4  # Every identifier in sql is quoted based on a comment in sqlite
       5  # documentation "SQLite adds new keywords from time to time when it
       6  # takes on new features. So to prevent your code from being broken by
       7  # future enhancements, you should normally quote any identifier that
       8  # is an English language word, even if you do not have to."
       9  
      10  def _iterdump(connection):
      11      """
      12      Returns an iterator to the dump of the database in an SQL text format.
      13  
      14      Used to produce an SQL dump of the database.  Useful to save an in-memory
      15      database for later restoration.  This function should not be called
      16      directly but instead called from the Connection method, iterdump().
      17      """
      18  
      19      writeable_schema = False
      20      cu = connection.cursor()
      21      yield('BEGIN TRANSACTION;')
      22  
      23      # sqlite_master table contains the SQL CREATE statements for the database.
      24      q = """
      25          SELECT "name", "type", "sql"
      26          FROM "sqlite_master"
      27              WHERE "sql" NOT NULL AND
      28              "type" == 'table'
      29              ORDER BY "name"
      30          """
      31      schema_res = cu.execute(q)
      32      sqlite_sequence = []
      33      for table_name, type, sql in schema_res.fetchall():
      34          if table_name == 'sqlite_sequence':
      35              rows = cu.execute('SELECT * FROM "sqlite_sequence";').fetchall()
      36              sqlite_sequence = ['DELETE FROM "sqlite_sequence"']
      37              sqlite_sequence += [
      38                  f'INSERT INTO "sqlite_sequence" VALUES(\'{row[0]}\',{row[1]})'
      39                  for row in rows
      40              ]
      41              continue
      42          elif table_name == 'sqlite_stat1':
      43              yield('ANALYZE "sqlite_master";')
      44          elif table_name.startswith('sqlite_'):
      45              continue
      46          elif sql.startswith('CREATE VIRTUAL TABLE'):
      47              if not writeable_schema:
      48                  writeable_schema = True
      49                  yield('PRAGMA writable_schema=ON;')
      50              yield("INSERT INTO sqlite_master(type,name,tbl_name,rootpage,sql)"
      51                    "VALUES('table','{0}','{0}',0,'{1}');".format(
      52                        table_name.replace("'", "''"),
      53                        sql.replace("'", "''"),
      54                    ))
      55          else:
      56              yield('{0};'.format(sql))
      57  
      58          # Build the insert statement for each row of the current table
      59          table_name_ident = table_name.replace('"', '""')
      60          res = cu.execute('PRAGMA table_info("{0}")'.format(table_name_ident))
      61          column_names = [str(table_info[1]) for table_info in res.fetchall()]
      62          q = """SELECT 'INSERT INTO "{0}" VALUES({1})' FROM "{0}";""".format(
      63              table_name_ident,
      64              ",".join("""'||quote("{0}")||'""".format(col.replace('"', '""')) for col in column_names))
      65          query_res = cu.execute(q)
      66          for row in query_res:
      67              yield("{0};".format(row[0]))
      68  
      69      # Now when the type is 'index', 'trigger', or 'view'
      70      q = """
      71          SELECT "name", "type", "sql"
      72          FROM "sqlite_master"
      73              WHERE "sql" NOT NULL AND
      74              "type" IN ('index', 'trigger', 'view')
      75          """
      76      schema_res = cu.execute(q)
      77      for name, type, sql in schema_res.fetchall():
      78          yield('{0};'.format(sql))
      79  
      80      if writeable_schema:
      81          yield('PRAGMA writable_schema=OFF;')
      82  
      83      # gh-79009: Yield statements concerning the sqlite_sequence table at the
      84      # end of the transaction.
      85      for row in sqlite_sequence:
      86          yield('{0};'.format(row))
      87  
      88      yield('COMMIT;')