In this section, we will talk about some features that will help us later in this chapter to solve SQL design traps. The main idea of the design techniques presented here is to control the SQL queries generated from our Universe. We will learn how to control the number of returned queries based on the selected objects.
An alias table, as discussed in Chapter 4, Creating the Data Foundation Layer, is a named copy of another database entity (table/view). We already learned how to create an alias table, and here we will learn how to use it to fix SQL design traps.
Context is a join path definition between Data Foundation entities. The SQL engine will create and submit a separate query for each context. This will only take place if we have a report or query that contains business objects that refer to more than one context. We will learn how to create context to fix SQL design traps in the SQL design traps section.