The repository SQL schema is a mapping of information model elements to SQL schema elements. The repository engine uses data in these tables to instantiate and manage COM objects. The repository SQL schema consists of a standard schema and an extended schema.
If you obtained Meta Data Services through SQL Server, repository SQL schema tables are located in the msdb system database.
You can add data to the repository SQL schema when you install an information model or create an information model programmatically. When you use a SQL Server database for your repository storage, the repository engine creates stored procedures to insert the data. For more information about how these stored procedures are named, see Naming Stored Procedures.
Although the extended schema is automatically generated, experienced model designers can tune the extended schema to optimize performance and data retrieval. For example, by default, the properties of each interface are stored in a separate SQL table. You can map the properties of multiple interfaces to a single table. You can also specify the column names and data types to be used for property data. You can add indexes to tables, but you must not remove indexes that have been automatically defined by Meta Data Services. For more information, see Tuning the Database Schema of an Information Model.
You can construct an SQL query to extract specific information from a repository. Although it is simpler to perform queries through generated views, you can manually build an SQL query against the repository SQL schema if you want a result set that covers more than one information model. To build such a query, you must be familiar with the repository tables. For more information about querying, see Repository SQL Tables and Generating Views.