The IliValue class works in close conjunction with the IliDatatype class. This class specifies the type of an IliValue object. An instance of the IliDatatype class exists for each supported type. The possible data types are:

The data type of an IliValue object constrains the set of values that it can hold. For example, an IliBooleanType object can hold three values: IlvTrue, IlvFalse, and null.

In addition to these predefined types, the Data Access library can dynamically synthesize new types. For a description of when this can occur, see Parameters. These types are collectively called structured types and fall in two categories: object types and table types. The section Structured Types at the end of this chapter explains how these types are used.