Schema Support

The OLE DB Provider session object supports the optional OLE DB IDBSchemaRowset interface. The ATL Object Wizard creates three schema classes in the session header file:

• CShortNameSessionTRSchemaRowset
  
  
• CShortNameSessionColSchemaRowset
  
  
• CShortNameSessionPTSchemaRowset

These classes respond to consumer requests for schema information. CShortNameSessionTRSchemaRowset handles requests for table information. CShortNameSessionColSchemaRowset handles requests for column information. The wizard supplies sample implementations for these classes, which return schema information for a DOS provider. CShortNameSessionPTSchemaRowset handles requests for schema information about the provider type. The default implementation provided by the wizard simply returns S_OK.

You can customize these classes to handle schema information appropriate to your provider:

• In CShortNameSessionTRSchemaRowset, you must fill out the catalog, table, and description fields (trData.m_szType, trData.m_szTable, trData.m_szDesc). The wizard-generated example uses only one row (table). Other providers may return more than one table.
  
  
• In CShortNameSessionColSchemaRowset, you pass the name of the table as a DBID.