PeopleSoft Application Engine is a PeopleTool used to carry out background SQL processing. Application Engines are neatly structured into blocks and offer an alternative to writing COBOL or SQR programs for background SQL processing.
Application Engine Program Types
Application Engine has five types of programs. We can specify the type in the Program Properties dialog box for your program definition. The types are:
1. Standard, which is a normal entry-point program.
2. Upgrade Only, which is used in PeopleSoft upgrade utilities.
3. Import Only, which is used by PeopleSoft import utilities.
4. Daemon Only, a type of program used as a daemon process.
5. Transform Only, a program type used to support Extensible Style sheet Language Transformations (XSLT).
Structure of an Application Engine
The key elements of an application engine program are:
A PeopleSoft App Engine can have one or more sections. Every App Engine should have at least one section called main section where the execution always start. A section can have multiple steps that get executed one after another.
Steps in an Section gets executed sequentially. Steps are the smallest unit of work that can be committed within a program. Each Step can have one or more actions.
Actions, unlike steps have a particular execution order. An Application has 9 Actions out of which two (SQL and Call Section ) are mutually exclusive. These steps are discussed in detail in the Application Engine Action article.
1. Do When
2. Do While
3. Do Until
4. Do Select
7. Call Section
8. Log Message
9. XSLT – found only in Transform Only programs
State Records are PeopleSoft records that are used to pass values from one action to another. They can be considered as storage locations for an Application engine. Find more about State records here.
Parallel Processing in Application Engines
Application Engine seamlessly supports Parallel Processing which helps faster processing when the data involved is huge. This is achieved by the use of temporary tables and %Table meta-SQL. PeopleSoft highly recommends programmers to make use of this feature.
Running an Application Engine
An application engine can be executed from the following 4 places:
1. From within Application Designer using Run Request
2. From PeopleCode using CallAppEngine()
3. From Process Scheduler
4. Manually from command prompt