Kbase 19651: Multiple Database Connections: SQL-89 versus SQL-92
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
6/25/2008 |
|
Status: Verified
GOAL:
SQL-89 and SQL-92 and multiple database connections.
FACT(s) (Environment):
Progress 9.x
FIX:
The release of the MERANT Version 3.6 DataDirect ODBC driver for SQL-89 makes it possible to have multiple Progress database connections from one data source with Progress Versions 7, 8, and 9. The new DataDirect ODBC driver replaces MERANT Version 3.5 which uses the Progress SQL-89 engine. This connectivity is not possible with Progress SQL-92 however.
When an initial connection is established, the DataDirect 3.6 ODBC driver passes the multiple database connection parameters to the Open Interface Broker (OIB). The OIB starts an Open Interface Driver (OID) for the connection and passes the database connection parameters to it. The OID is in effect a 4GL client with a different user interface. It handles connections to multiple Progress databases
just as a Progress 4GL client does. Here, the OID handles joins across multiple databases and passes a single result set back to the ODBC driver.
A connectivity quirk when using Progress 4GL and SQL-89 can work to a users advantage. Here, the OID acts as middleware that performs a join across multiple databases and makes separate queries. It is, however, invisible to the ODBC driver and ODBC client application.
There is no middleware scenario with the SQL-92 engine. The SQL-92 ODBC driver connects directly to the database broker which spawns a SQL-92 server specifically for this database. This server connects to the shared memory of this one database only. If multiple database connectivity is needed from an ODBC client, the client application must make these connections.