Application Engine
1. It is a PeopleTool and It is used to develop batch programs or online programs that perform the backed processing against the data.
2. It consists of the 2 distinct components.T hey are
Designer->Consists of the batch programs.
Runtime Environment->To run and monitor the programs.
3. A program is a set of SQL statements.
4. It does not generate SQL or PeopleCode, but it executes SQL or PeopleCode as a part of the program.
5. It is designed for batch processing where data must be processed without user interaction.
6.AE resides on the database server.
APPLICATION ENGINE PROGRAM ELEMENTS:
1.PS AE consists of a set of processes to execute a given task and made up of several elements. They are
i) Sections
It is a set of ordered steps that gets executed as a part of the program.The execution of the program starts with the section defined as MAIN.
ii) Steps
Steps are the smallest unit of the program that can be committed within a program.It is used to execute the PeopleCode
command or log a message with the step. When the section gets called, its steps execute sequentially.
iii) Actions
Multiple actions can be within a step. There are 5 multiple actions they are
Do Action:
Do actions contain a SQL statement that is designed to return the results on which subsequent actions depend.
It is equivalent to a COBOL perform statement. There are 4 types of Do actions they are:
1)Do While 2)DO When 3)Do Select 4)Do Until.
SQL AND CALL SECTION ARE MUTUALLY EXCLUSIVELY ACTIONS WHICH CANNOT BE PERFORMED ONCE ATA TIME COZ IT CAUSES DEADLOCKS
SQL:
It contains a single SQL statement. There are 4 types of SQL statements. They are
1)Update 2)Delete 3)Insert 4)Select
PeopleCode:
It provides an excellent way to build dynamic SQL, performs simple if/else edits, set defaults and other operations that
don't require a trip to the database
Log Message:
Call Section: It is used to call and insert an action in the program or outside the program.
iv) State Records
It is a PeopleSoft Record that must be created and maintained by the Application Engine developer.
This record defines the fields a program uses to pass values from one action to another.
It can be either a Physical record or a work record, any no of state records can be associated with a program.
Physical state records must be keyed by a process instance.
META-SQL
1. Meta-SQL is a set of predefined terms designed to replace RDBMS syntax.
2.PS meta-SQL enables us to dynamically generate portions of SQL code. (EX;--2 joins 2 tables based on their common keys)
3.%select->It is used to insert values of variables into state record.
4.%bind->It is used to get values.
SQLEXEC();
By using the SQLEXEC() function we can do the data manipulation (Insert, Update and Delete).
Example:
SQLEXEC("select * from PS_JOB where X.EMPID.vlaue=:1",abc,&emplid1")
The main drawback of using this SQLEXEC() function is "It will return only one value at a time".
State Records:
It is a working storage.
It is a physical record or derived work record
It passes values from section to section, Action to Action and steps to step.
We can use "N" no of state records in a program.
It consists of Runcontrol ID and Process Instance ID.
If it is a physical record then process Instance ID must be keyed.
It maintains temporary data in AE programs for online processing.
Advanced Tab
1.Disable Restart
2.Application Library
3.Batch only
4.Message Set
5.Program Type (STD,Upgrade,Import,Daemon,Transform)
Restating an AE program
The Key feature of AE is Restart.
Sate record should be a physical record. When the system is processing a huge amount of data (batch processing) and if there
occurs any failure through the environment then the restartable logic comes in to picture. The cursor directly comes into the checkpoint where the commit is set to upend restarts the program from that point.
We can restart the program from the process request page.
AERUNCONTROL record saves all the information that is required for a program to restart.
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