FirebirdSQL logo
 Data Manipulation (DML) StatementsBuilt-in Scalar Functions 

ON EXTERNAL [DATA SOURCE]

With ON EXTERNAL [DATA SOURCE], the SQL statement is executed in a separate connection to the same or another database, possibly even on another server.If connection_string is NULL or “''” (empty string), the entire ON EXTERNAL [DATA SOURCE] clause is considered absent, and the statement is executed against the current database.

Connection Pooling

  • External connections made by statements WITH COMMON TRANSACTION (the default) will remain open until the current transaction ends.They can be reused by subsequent calls to EXECUTE STATEMENT, but only if connection_string is identical, including case

  • External connections made by statements WITH AUTONOMOUS TRANSACTION are closed as soon as the statement has been executed

  • Statements using WITH AUTONOMOUS TRANSACTION can and will re-use connections that were opened earlier by statements WITH COMMON TRANSACTION.If this happens, the reused connection will be left open after the statement has been executed.(It must be, because it has at least one active transaction!)