Re: DIfference between Schemas, PCRS' FUnctions and Operations

Question

Dear SAPExperts,
Can anybody pls tell me what is difference between Schemas, PCRS' Functions and Operations.
Thanx in advance
Regards
Aniruddha

Answer 1

Hi Aniruddha
When the payroll driver is executed (for ex: PC00_M40_CALC for INDIA is executed) the schema IN00 (standard schema) is executed and it calls certain functions (functions may use Rules. Rules contain Operation) and also subschemas.
Functions could be of four types
1. Performing some payroll computations (E.g. INEPF function calculates the PF amount of an employee during payroll run)
2. Calling rules (E.g. P0045 function calls a rule INLN to compute the loan details of a personnel number).
3. Getting data from Infotypes (E.g. P0581 will get the data from Infotype-581 for payroll processing).
4. For some decisions. (E.g. IF & ENDIF function is used to execute as per the true and false decisions) etc.
When the PY is executed SAP uses lot of Internal Tables to store data and also provides data to other internal tables.
The read and change access to Internal Tables is enabled using functions that are executed in a personnel calculation schema and using operations that are executed in personnel calculation rules.
The following is just an attempt to provide some info on how Functions are processed during the PY Run. For ex: (functionality of subschema XIN0 and INBD)
1. INITIALIZATION OF PAYROLL: When the Payroll is executed first the subschema XIN0 is called,   This subschema comprises the following main steps:
I.     Specify program type (payroll or evaluation)
II.     Set switch for database updates (YES/NO) all database updates are controlled via this switch (otherwise simulation)
III.     Only infotypes from the HR master record which apply to the selected personnel number are read.
IV.     All Time Management infotypes are imported.
V.     Specify check against control record PA03 (test or live).
2. READ BASIC DATA: Once the Initialization of Payroll is successful, the subschema INBD is called. This subschema reads the Basic data of an employee who is there in the Payroll execution. Basic Data includes, determining Employee Name, Reading Work Center/Basic Pay Data, Setting Financial Year Dates and Allowance Grouping Tables, Reading Previous Employment Tax Details, Reading Housing (HRA/CLA/COA), Reading Exemptions, Reading Income from Other Sources, Reading Section 80 Deductions, Reading Investment Details (Sec 88), Reading Provident Fund Contributions, Reading Other Statutory Deductions, Reading Car and Conveyance, Reading Long Term Reimbursements, Read ID Details. Function GON checks whether all the master data has been imported, no further processing of schema will occur unless certain data is present.
The Subschema INBD calls the following functions in order to read the Basic Data:
ENAME :
Function ENAME reads the last valid name of the employee in the payroll period. The formatting used for the country in question is used when displaying this name.
WPBP
If an employee receives a pay increase within a payroll period, the Basic Pay infotype (0008) is changed and delimited as of a specific date. Two data records exist for one payroll period.
During payroll, the system writes the Basic Pay wage type to the results table with two different indicators. These split indicators are a link to the WPBP table that contains the relevant values. The system takes into consideration both data records for the corresponding partial periods when calculating remuneration.
ININI
P0580
P0581
P0582
P0584
P0585
P0586
P0587
P0588
P0583
P0590
P185I
GON :
                Function GON checks whether all the master data has been imported. No further processing of the schema will occur unless certain data is present. Checking procedures vary from country to country. There must always, however, be a work center (P007).
[Def. of Functions, Rules and Operations (copied from Raju's answer)
Schema is a collection of functions
A Rule is a collection of operations.
An operation is a very basic piece of logic that is used, mostly, to manipulate wage types
Best Regards
Reddy