We have talked a little bit about how we can have multiple logical table sources behind each logical table. This supports the federation and fragmentation of data, and is an extremely important part of OBIEE's capability. This is an advanced topic, but we will provide an introduction to advanced LTS functionality with an example of fragmentation. There are three main scenarios where we require multiple logical table sources.
This is used when we have aggregate tables in our schema. An aggregate table is a summary of our base data at a higher level of one or multiple dimensions. This is usually created to improve query performance. We can introduce an aggregate table as a new LTS. As we have done with our previous level-based measure, we can set the content for the whole LTS to the appropriate level in one of our dimensions. Logical columns will be mapped to both sources and OBIEE will then choose to utilize the...