Reg: Change Pointers

Former Member — Fri, 29 Sep 2006 06:11:58 GMT

want the end-to-end implementation of change pointers

Re: Reg: Change Pointers

Former Member — Fri, 29 Sep 2006 11:09:22 GMT

Hi Ramesh,

Change pointers is a concept to record creation, changes and deletion of records.

The data are stored in CDHDR and CDPOS tables.

Regards

Arun

Re: Reg: Change Pointers

Former Member — Fri, 29 Sep 2006 11:12:26 GMT

ALE Change Pointers

Applications which write change documents will also try to write change pointers for ALE operations. These are log entries to remember all modified data records relevant for ALE.
Most applications write change documents. These are primarily log entries in the tables CDHDR and CDPOS.

Change docs remember changes in transaction
Change documents remember the modified fields made to the database by an application. They also remember the user name and the time when the modification took place.

Data elements are marked to be relevant for change documents
The decision whether a field modification is relevant for a change document is triggered by a flag of the modified field’s data element. You can set the flag with SE11 by modifying the data element.

ALE may need other triggers
For the purpose of distributing data via ALE to other systems, you may want to choose other fields, which shall be regarded relevant for triggering a distribution.

Therefore R/3 introduced the concept of change pointers, which are nothing else than a second log file specially designed for writing the change pointers which are meant to trigger IDoc distribution via ALE.

Change pointers remember key of the document
So the change pointers will remember the key of the document every time when a relevant field has changed.

An ABAP creates the IDocs
Change pointers are then evaluated by an ABAP which calls the IDoc creation, for every modified document found in the change pointers.

Change pointers are when change documents have been written
The Change pointers are written from the routine CHANGEDOCUMENT_CLOSE when saving the generated change document. So change pointers are automatically written when a relevant document changes.

The following function is called from within CHANGEDOCUMENT_CLOSE in order to write the change pointers.

CALL FUNCTION 'CHANGE_POINTERS_CREATE'
EXPORTING
change_document_header = cdhdr
TABLES
change_document_position = ins_cdpos.

Activation of change pointer update
Change pointers are log entries to table BDCP which are written every time a transaction modifies certain fields. The change pointers are designed for ALE distribution and written by the function CHANGE_DOCUMENT_CLOSE.
Change pointers are written for use with ALE. There are ABAPs like RBDMIDOC which can read the change pointers and trigger an IDoc for ALE distribution.

The change pointers are mainly the same as change documents. They however can be set up differently, so fields which trigger change documents are not necessarily the same that cause change pointers to be written.

In order to work with change pointers there are two steps to be performed

·Turn on change pointer update generally

·Decide which message types shall be included for change pointer update

Activate Change Pointer Generally
R3 allows to activate or deactivate the change pointer update. For this purpose it maintains a table TBDA1. The decision whether the change pointer update is active is done with a

Function Ale_Component_Check

Currently (release 40B) this check does nothing else than to check, if this table has an entry or not. If there is an entry in TBDA1, the ALE change pointers are generally active. If this table is empty, change pointers are turned off for everybody and everything, regardless of the other settings.

The two points read like you had the choice between turning it on generally or selectively. This is not the case: you always turn them on selectively. The switch to turn on generally is meant to activate or deactivate the whole mechanism.

reading the change pointers which are not yet processed
The change pointers which have not been processed yet, can be read with a function module.

Call Function 'CHANGE_POINTERS_READ'

RBDMIDOC
The ABAP RBDMIDOC will process all open change pointers and distribute the matching IDocs.

Use Change Documents Instead Of Change Pointers
When you want to send out an IDoc unconditionally every time a transaction updates, you better use the workflow from the change documents.

Dispatching ALE IDocs for Change Pointers
Change pointers must be processed by an ABAP, e.g. RBDMIDOC.
RBDMIDOC processes change pointers and sends the IDocs
The actual distribution of documents from change pointers must be done by an ABAP, which reads the change pointers and processes them. The standard ABAP for that is RBDMIDOC. For recurring execution it can be submitted in a scheduled job using SM35 .

Function module defined in table TBDME
It then calls dynamically a function module whose name is stored in table TBDME for each message type.

Call Function Tbdme-Idocfbname
Exporting
Message_Type = Mestyp
Creation_Date_High = Date
Creation_Time_High = Time
Exceptions
Error_Code_1.

Example
A complex example for a function module, which collects the change pointers, can be examined in:

MASTERIDOC_CREATE_SMD_DEBMAS .

This one reads change pointers for debtors (customer masters). During the processing, it calls the actual IDoc creating module MASTERIDOC_CREATE_DEBMAS .

To summarize the change pointer concept

·Change pointers record relevant updates of transaction data

·Change pointers are written separate from the change documents, while at the same time

·Change pointers are evaluated by a collector run

BDCPS
Change pointer: Status

BDCP
Change pointer

BDCPV
A view with BDCP and BDCPS combined: Change pointer with status

TBDA2
Declare activate message types for change pointers with view V_TBDA2.or transaction BD50 or .
SALE -> Activate change pointers for message types

TBD62

The view V_TBD62 defines those fields which are relevant for change pointer creation. The table is evaluated by the CHANGE_DOCUMENT_CLOSE function. The object is the same used by the change document. To find out the object name, look for CHANGE_DOCUMENT_CLOSE in the transaction you are inspecting or see table CDHDR for traces.

Figure 26: Tables involved in change pointers processing

Sample content of view V_TBD62

Object

Table name

Field

DEBI

KNA1

NAME3

DEBI

Kann1

ORT01

DEBI

Kann1

REGIO

Re: Reg: Change Pointers

former_member404244 — Fri, 29 Sep 2006 11:17:15 GMT

Hi Ramesh,

iam giving the tcodes for chage pointers.

1>WE81

2>WE31

3>WE31

4>WE82

5>SCDO

6>BD50

7>BD52

8>BD61

9>BD60

10>WE20

11>BD64.

THE TALES U SHOULD LOOK ARE

1>CDHDR

2>CDPOS

3>BDCP

Regards,

Nagaraj

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