Guidelines for Configuring a Base Table or Configuring a One-To-Many Extension Table

You can use the following guidelines to help you decide to add an extension column to a base table or to use columns in a one-to-many extension table:

• Try to use a predefined one-to-many extension table or column to meet design requirements. They are predefined and already part of the data objects layer so they do not require you to modify the Siebel schema or the physical database. If a predefined extension table or column is not available, then explore other options, such as creating a new extension table.

• Add an extension column to a base table if the data you must store almost always exists for a base record, and if Siebel CRM does not regularly access it. This configuration often results in better performance because it avoids the join that an extension table uses. It can result in slower access to the base table if a lot of data exists where numerous large fields are added and where these fields always contain data. In this situation, fewer rows fit on one page.

  If a user query regularly includes an extension column, then it is likely that an index is required on the column that Siebel CRM must include on another base table column. You must add it to the base table.

• If one-to-many extension fields are required, and if the user only infrequently accesses the view that displays this data, then you can use columns in a one-to-many extension table. In this situation, Siebel CRM uses the join for the extension table, but only if the user accesses this view.