Vendor Specific functions

[bloggerman]

What are vendor specific functions and how are they different from Cognos functions? Are any of the two always executed on the Cognos server as compared to teh database

How do you identify Cognos functions from ?

[saumil287]

Hi,
Vendor specific functions are for the database
eg
If your database is Oracle,then you have to use functions of Oracle.

The cognos functions are cognos inbuilt functions
These functions work for any database except excel and csv files.
The processing defines whether query functions should be executed in cognos or Database only.
Anyone Please post other answers if I am wrong.

Thanks

[blom0344]

A Vendor specific function should - ideally - only be used if a Cognos equivalent is not available. The Cognos equivalent is 'translated' by the query engine to the RDBMS equivalent at runtime and executed within the SQL. Some Cognos functions have NO direct RDBMS equivalent and are used by the Cognos server AFTER query execution. Best example are the running_XXX functions.

Best practice is to abstain from RDBMS specific functions and let Cognos decide how it translates at runtime

[bloggerman]

So if cognos functions are translated and at times processed afterwards on the Cognos server, wouldnt they they be slow?

Are all Vendor specific functions executed on the database?

[blom0344]

So if cognos functions are translated and at times processed afterwards on the Cognos server, wouldnt they they be slow?

Are all Vendor specific functions executed on the database?

Running aggregates do not exist as independent RDBMS functions, hence the participation of the cognos server to calculate them. When using running aggregates you will notice that they are missing from the SQL that Cognos proposes

If a function - cognos or vendor specific -  is used it should not have any influence on performance I guess and keeping things within Cognos dialect will give maximum flexibility..

And yes, vendor specific functions are strictly RDBMS functions , so they are used within the SQL that is generated

[bloggerman]

So, are all functions other than vendor specific functions cognos functions?

Also, are all cognos functions always executed on the cognos server or can they be executed on the database entirely as well. If they can be executed on the database as well entirely what decides where they would be executed...other than Database Only and Limited Local

[blom0344]

A typical cognos function is compiled (translated) to the required syntax depending on the RDBMS. Compare Cognos and native SQL propositions and you will see what I mean..