Regarding schemas and pcrs

Question

Hi gurus,
Though i know about schemas and pcrs..i ahve a small confusion..can anybody clarify me these questions?
1)why we use schema and functionality of the schema?
2)why we use subschema and functionality of subschema?
3)what are the parameters1,2,3,4.
   why do we use these paremters?
   and how it helps... where can we get the documentation for parameters?
4) what an Function does for schema and subschema?
5)what an operation does?
//jack//
Edited by: michael jack on May 22, 2008 8:47 AM
Edited by: michael jack on May 22, 2008 8:57 AM

Answer 1

In simple words schema guides Payroll driver that following path will follow for processing of info types in system. for example if u see the payroll log just think that why infotype 0001 read at start whey system creates bank payment after reading all data? this is all schema
Second part is subschema help schema if you have little know how of programming you can take it as conditional loop sort of things. :).
Technical detail is as under (From sapexpert.com)
Each country payroll version supported by SAP has a program called the "payroll driver" that calculates payrolls. For example, in the U.S., the payroll driver is RPCALCU0, in Mexico it is HMXCALC0, in Canada RPCALCK0 and for international RPCALCX0. Each one is different, but they share a common core of functionality. The job of the payroll driver is to process payroll functions as specified in a payroll schema. These payroll functions each perform a specific job, for example - reading data from infotypes, calculating taxes, and processing wage types. Some functions process payroll rules. Rules are a collection of payroll operations. Each operation does a small unit of work, such as multiplying a wage typeu2019s number by a rate to get an amount.
Schemas are edited with transaction PE01, and rules                                                                               
with PE02. Functions and operations are maintained with transaction PE04. To view payroll results,
use transaction pc_payresult (or in earlier R/3 releases go to Tools>Payroll result>Display in the Payroll menu). (See Figure 1.)The standard payroll schema for a country can be derived from table T500L (see the screen blow). If the country in table T500L has an X in the Old Naming Conv field, then the schema is HR Country Indicator plus 000. Otherwise, it is the ISO Code plus 00. So the U.S. has schema U000, for Mexico it is MX00 and for international its X000.
Good Luck
Syed