Users frequently need to see the data from more than one table at once. This data can be joined at query time, or in advance by creating a join index. Sometimes you can improve query performance by creating a join index for columns that are joined in a consistent way.
Because join indexes require substantial time and space to load, you should create them only for joins needed on a regular basis. Sybase IQ join indexes support one-to-many and one-to-one join relationships.
