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What is CIS and how can I use it?
CIS is the new name for Omni ASE. The biggest difference is that CIS is included with Adaptive Server Enterprise as standard. Actually, this is not completely accurate; the ability to connect to other ASEs and ASEs, including Microsoft's, is included as standard. If you need to connect to DB2 or Oracle you have to obtain an additional licence.
So, what is it?
CIS is a means of connecting two servers together so that seamless cross-server joins can be executed. It is not just restricted to selects, pretty much any operation that can be performed on a local table can also be performed on a remote table. This includes dropping it, so be careful!
What servers can I connect to?
* Sybase ASE
* Microsoft SQL Server
* IBM DB2
* Oracle
What are the catches?
Well, nothing truly comes for free. CIS is not a means of providing true load sharing, although you will find nothing explicitly in the documentation to tell you this. Obviously there is a performance hit which seems to affect cursors worst of all. CIS itself is implemented using cursors and this may be part of the explanation.
OK, so how do I use it?
Easy! Add the remote server using sp_addserver. Make sure that you define it as type sql_server or ASEnterprise. Create an "existing" table using the definition of the remote table. Update statistics on this new "existing" table. Then simply use it in joins exactly as if it were a local table.
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