DRS stage

kollurianu · Post by **kollurianu** » Mon Mar 21, 2005 2:24 pm

Can some one explain me what is purpose and function fo DRS stage in DS7.5 , how it different from ODBC stage.

thank you,

chulett · Post by **chulett** » Mon Mar 21, 2005 2:40 pm

The Dynamic Relational Stage allows you to connect to any supported database with a single stage, which means you could (theoretically) swap out your underlying database and only have to change a single parameter to continue to use the same jobs. Reality is a harsh mistress, however, and it doesn't always work out that easily.

If there is a supported 'native' interface for the RDBMS then the DRS stage will use that (like OCI for Oracle) otherwise it will fall back on ODBC.

This is all documented with the product.

ray.wurlod · Post by **ray.wurlod** » Mon Mar 21, 2005 3:14 pm

There is no automatic selection of access protocol in version 7.1; you must inform the DRS whether to use ODBC or a native type. This can be a job parameter.

vmcburney · Post by **vmcburney** » Mon Mar 21, 2005 5:08 pm

I go for the native database stage first as it tends to have the most functionality and the fastest performance. The Oracle OCI stage in particular has a query builder and a synchronise columns option that are missing from the DRS and ODBC stages.

If I need the switch database ability I go for the DRS stage.

The ODBC stage comes with a stored procedure query type and a multiple row lookup option that sometimes make it preferable. It also has less installation issues. Native connectivity requires the installation of the RDBMS client on the DataStage server whereas the ODBC drivers are installed with DataStage.

No matter what type of database stage I use I always try to use generated SQL as this makes maintenance and metadata reporting a lot easier.