Developing and Deploying Siebel Business Applications > Configuring the House and Opportunity Entities > Configuring the House Detail - Appraisals View >
About Standard 1:M Extension Tables
One-to-many extension tables are predefined tables that have one-to-many relationships with base tables. They have generic columns that you can use to store additional data. You can extend the data model for your purposes and track entities that are not part of the standard Siebel data model. Because the extension tables themselves are already part of the data model, you do not need to modify the database schema.
When using a one-to-many extension table to store data, you use the TYPE column to group records. You create a new business component for the entity to be tracked. The business component must have a Type field that defaults to a unique value and a search specification that finds only those records that contain this value. For details of how this is accomplished, read Creating the Appraisals Business Component. With this practice you can use a single one-to-many extension table to store data for multiple business components. However, this practice must also be followed when the extension table is used by only one business component.
NOTE: There are more than 20 one-to-many extension tables in the standard data model. The names of one-to-many extension tables contain the suffix _XM.