Exploring the Inverse Functions Sample This page last changed on Dec 31, 2008. ## Exploring the Inverse Functions Sample This topic describes the components that comprise the inverse functions sample. #### Topic Map Exploring the Inverse Functions Sample Exploring the Sample Exploring the Projects Related Topics Using Inverse Functions to Improve Query Performance ### Exploring the Sample The inverse functions sample consists of two projects. ##### Inverse Function Sample 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
##### Inverse Function Projects ### Exploring the Projects This section describes the principal entities within the two projects that comprise the inverse functions sample. #### Exploring the InverseFnHowTo Dataspace Project 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.
#### Exploring the JavaFunctionLib Project 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.
### Related Topics ##### Concepts Using Inverse Functions to Improve Query Performance Deconstructing the Inverse Functions Sample ##### How Tos Setting Up the Inverse Functions Sample

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