Expression Classes
Class RWDBExpr is a base class for a family of classes in the DB Interface Module that enable you to program SQL expressions in C++. Instances of these expressions are usually created anonymously. For example, the following fragment instantiates several RWDBExpr objects:
select.where(myTable["col1"] < yourTable["col1"] + 100);
Additional classes in this category include RWDBAssignment, RWDBCriterion, RWDBCollectableExpr, RWDBBoundExpr, RWDBJoinExpr, RWDBSimpleCaseExpr, and RWDBSearchedCaseExpr. Chapter 5, The Data Manipulation Classes, contains more examples of using these classes.The DB Interface Module also provides an extensible mechanism for defining SQL expressions for your specific needs. The classes RWDBExprFormDefinition, RWDBExprFuncDef{n}, RWDBCritFormDefinition, and RWDBCritFuncDef{n}support this mechanism. They are discussed in the SourcePro API Reference Guide.
