Expressions
Expressions are language constructs that resolve to a value, a set of values, or TRUE or FALSE. Expressions can contain a wide variety of language elements. For example, you can use:
• Literals
• Variables
• Named constants
• Values returned by procedures
• Arithmetic and string expressions
• Logical (boolean) expressions
In addition, OpenROAD lets you use all the operators and functions of the Ingres DBMS.
Expressions are used widely in 4GL. For example, the value of an expression can:
• Be assigned to an OpenROAD variable
• Be used as part of a search condition in a query statement
• Serve as a condition in an OpenROAD if or while statement
The following subsections describe the language elements that you can use in expressions.