sqlalchemy.dialects.firebird.fdb

The fdb dialect is based on the sqlalchemy.dialects.firebird.kinterbasdb dialect, however does not accept every argument that Kinterbasdb does.

• enable_rowcount - True by default, setting this to False disables the usage of "cursor.rowcount" with the Kinterbasdb dialect, which SQLAlchemy ordinarily calls upon automatically after any UPDATE or DELETE statement. When disabled, SQLAlchemy's CursorResult will return -1 for result.rowcount. The rationale here is that Kinterbasdb requires a second round trip to the database when .rowcount is called - since SQLA's resultproxy automatically closes the cursor after a non-result-returning statement, rowcount must be called, if at all, before the result object is returned. Additionally, cursor.rowcount may not return correct results with older versions of Firebird, and setting this flag to False will also cause the SQLAlchemy ORM to ignore its usage. The behavior can also be controlled on a per-execution basis using the enable_rowcount option with _engine.Connection.execution_options:

  conn = engine.connect().execution_options(enable_rowcount=True)
  r = conn.execute(stmt)
  print(r.rowcount)
  

• retaining - False by default. Setting this to True will pass the retaining=True keyword argument to the .commit() and .rollback() methods of the DBAPI connection, which can improve performance in some situations, but apparently with significant caveats. Please read the fdb and/or kinterbasdb DBAPI documentation in order to understand the implications of this flag.

  Changed in version 0.9.0: - the retaining flag defaults to False. In 0.8 it defaulted to True.

  See Also

  https://pythonhosted.org/fdb/usage-guide.html#retaining-transactions - information on the "retaining" flag.