Exploring the Inverse Functions Sample

This page last changed on Dec 16, 2008.

This topic describes the components that comprise the inverse functions sample.

The inverse functions sample consists of two projects.

Project	Description
InverseFnHowTo	The inverse functions sample dataspace, including the top-level data service, a relational physical data service, physical data services corresponding to Java transformation functions, and utility data services.
JavaFunctionLib	A Java project that defines the functions used for transforming the da

This section describes the principal entities within the two projects that comprise the inverse functions sample.

The following table describes the data services defined in the InverseFnHowTo dataspace project:

Data Service	Description
Employee	The top-level data service for the project. Examining the query plans for the read methods in the data service shows that predicates are pushed despite data transformations because of inverse functions.
EMP2	The physical data service that accesses the data in the underlying relational database.
DeptFunc EmpIdFuncs NameFuncs	The physical data services corresponding to the Java transformation functions in the JavaFuncLib project.
EMP2Util	Contains functions useful for manipulating and fixing the sample data through the test view.

The following table describes the data services defined in the JavaFunctionLib project:

Class	Method	Description
DeptLib	deptname()	Converts a department number to a department name.
	deptno()	Converts a department name to a department number.
EmpIdLib	empid()	Converts an employee number to a string of the following format: EMPid_number.
	empnum()	Converts a string of format EMPid_number to an employee id.
NameLib	firstname()	Extracts the first name from a string (containing a person's full name).
	lastname()	Extracts the last name from a string (containing a person's full name).
	fullname()	Concatenates the first and last name to form a full name.