Minischemas are graphical models of the tables or text files in one or more data source connections. You can create a minischema during the data source connection creation process, or you can create a minischema later, from data sources to which you have already connected.
For most data source types, minischemas are displayed similar to a logical model in an entity relationship diagram, showing joins between tables and categorizing values in the source database as dimensions. You can choose the tables to include in a minischema, so the tables displayed can be a subset of the data from one or more data sources.
Minischemas enable you to bring in a subset of tables from one or more data source connections in order to create a subject area on which to base further modeling.
You can perform these tasks in minischemas:
Add or delete joins between tables, manually or by using inspection, where you select from a list of possible joins
Note:
If you are accessing Oracle BI EE or text file data sources, you may create a minischema, but only self joins within a file are supported.
View sample data from tables or columns
Create metadata elements
Add color to table headings in the minischema diagram, which can be useful as a visual aid
Minischemas are discussed as part of the data source creation process in Selecting a Minischema Option for Relational Sources.
Figure 1, Example Minischema is a sample minischema.
You can create any number of minischemas per data source. Multiple minischemas are a convenient way to create alternate views of a data source. An alternate minischema may contain, for example, a subset of the objects in the data source or additional joins.