Ensure that your standard schemas are up to date and avoid the risk of missing important SAP updates in your modified schemas.
Key Concept
Standard SAP Releases 4.6C through SAP ERP Central Component provide Payroll and Time Management schemas, which customers either copy to their own versions (local clients) for further modifications or call from their schemas. Most payroll experts use these standard schemas as a point of reference within their system.
Do you make changes to an SAP standard schema in your development client? For example, you might apply an SAP Note fix or add documentation to a schema call or function. If the answer to this question is yes, then your SAP standard schemas may not be as up to date as you imagine.
SAP standard schemas are stored in client-independent table T52C0. However, if any edits are made, they are stored in client-dependent table T52C1, therefore creating a local copy of the schema. All updates applied to the standard schema in client 000 are not reflected in the modified schema in your local client (client 100).
Most companies believe their SAP standard schemas are up to date because they apply HR Support Packages (SPs) in a timely fashion. This is not necessarily the case. Use the following best practices to determine how up to date your SAP standard schemas for Payroll and Time Management really are and how to resolve discrepancies:
1. Understand what happens when you amend a schema in a development client
2. Recognize if changes have been made to your productive client
3. Learn how to revert your schemas back to the SAP standard
Note
With a standard installation, SAP delivers 000, 001, and 066 clients. Client 000 is the SAP reference client and it should not be changed or deleted. Other local clients could be created as copies of client 000. In this article, client 100 is used to reference a development client in the user’s system.
What Happens When You Amend a Schema?
In my example, I employ SAP user ID MOOGANIA to look at SAP standard schema AEND in the development client 100. Figure 1 illustrates the standard structure for this schema.

Figure 1
SAP standard schema AEND structure
Transaction PE01 is used to edit, create, or display payroll schemas. When you execute transaction PE01 to edit or display a schema, SAP HR overlooks the development client (client 100) and reads the schema structure directly from the SAP Reference Client (client 000). You may want to add a comment line when you start editing the schema to make it clear to the payroll team what SAP changes are being made in the schema. In this example, comment text is added at line 20 to inform the payroll team of the schema updates (Figure 2).

Figure 2
The text in line 20 indicates a change has been made in client 100 to standard schema AEND
Changes to Client 100
It is important to note that when you make changes to the schema in client 100, you are actually saving your changes to a local copy of the schema in your development client. Any further changes will not be carried through to client 000 and your SAP system does not update the standard version in client 000 with your new modifications. There is now a discrepancy between your saved schema in client 100 and the SAP standard in client 000.
If you look at the schema attributes in both clients, you see details of the changes that were made by user MOOGANIA on 28.08.2007 in the development client (client 100), as shown in Figure 3. However, the standard client (client 000) stays the same and was last modified by SAP on 09.09.1998 (Figure 4).

Figure 3
Schema AEND attributes from client 100

Figure 4
Schema AEND attributes from client 000
Changes to Client 000
On the other hand, if schema changes are applied in client 000 (if you apply an HR SP that contains changes to your schema, for example) then these changes are saved directly in client 000. These are standard SAP changes and the method SAP employs only updates the standard schemas in client 000. Although client 000 is updated, the local copy that you have already modified in client 100 will not be updated accordingly. Your local copy (client 100) isn’t connected to the standard version (client 000).
You can simulate the changes applied to the standard version by adding more lines to your schema in client 000, as shown in Figure 5. The master language for the schema is exclusively in German to prevent inconsistencies in the descriptive texts. Lines added in my example simulate the changes applied to the client 000 version of the schema demonstrating that the changes do not get carried through to the version in client 100. The fact that these changes are being made in client 000 means that client 100 will be unaffected (Figure 6).

Figure 5
Amendments made to schema AEND in client 000

Figure 6
Changes made in client 000 are not reflected in the client 100 version of schema AEND
How Do You Determine If Changes Occurred In Your Development Client?
Transaction PE01 contains two ways to identify changes in your SAP development client — compare and last changed by. You need to pinpoint these changes because any SAP-delivered changes in client 000 are not reflected in your local copy of the schema, which is the one you probably reference more often.
Compare Option
The compare option in transaction PE01, which is available in all versions of SAP HR, helps you identify any differences between a schema and the SAP standard version contained in client 000.
First, select your schema using either the drop-down menu or by entering the schema name directly. Then select the Use standard schema, Compare texts, and Display differences only check boxes, as shown in Figure 7. To generate the results, click on the green check mark. If differences exist, the screen that appears identifies them automatically (Figure 8).

Figure 7
The compare schemas option available in transaction PE01

Figure 8
Compare schema AEND from client 100 to display differences with client 000
As shown in Figure 4, the schema attributes indicate that user ID MOOGANIA updated the schema on 29.08.2007 in the local client. On the other hand, the client 000 version was last changed by user BASIS on the same day. The details of the differences are displayed in the lower portion of the screen. In this example, you see that line 3 was deleted.
Last Changed By Option
In SAP releases up to and including R/3 4.7, you can use the Schema Directory function in transaction PE01 to view a list of your SAP schemas attributes. To access this function, execute transaction PE01. In the initial screen that appears, select Schema Directory from the drop-down menu in field Schema to generate the screen shown in Figure 9.

Figure 9
Schema Directory selection screen
The Payroll and Time Management option is defaulted automatically. Under the Versions tab, select Standard schemas only and click on the execute icon
. In the window that appears, click on the Attributes button to generate the screen shown in Figure 10.

Figure 10
Schema directory output displays a list of schema attributes
In the Last changed by column, you can see if the object has been modified by anyone. If someone besides SAP (in an HR SP, for example) was the last to modify an object, then it could potentially be outdated. You need to investigate all the modified objects using the schema compare option to remove discrepancies between SAP standard schemas in your local clients. In later SAP releases this method of identifying changes by the Last changed by column is not available because the Schema Directory function reads the schema attributes from client 000 without regard to the changes in client 100.
How Do You Revert Your Schema to SAP Standard?
If you want to revert your schema to SAP standard to remove any present or future discrepancies that prevent the SAP updates from being applied, take the following steps in your local client (client 100, in this example):
Step 1. Save a copy. If you want a log of history any changes that you made, save a copy of your schema first. I recommend adding a Z at the beginning of the name to indicate that it is a copy. However, the following steps that suggest deleting a standard SAP schema are safe and do not result in lost data. There is no need to worry; your SAP system does not allow you to delete the client 000 copy from another client.
Step 2. Delete the schema. In transaction PE01, select schema AEND and click on the delete icon
. When the system displays a pop-up window warning you that you could lose data, confirm that you want to delete the schema by selecting the Yes button. A confirmation message of your deleted schema appears in the status bar at the bottom of the screen (Figure 11).

Figure 11
Deletion of the local copy of schema AEND
Step 3. Display client 000. If you now select schema AEND again in PE01 and click on the Display button, you see that that the system is reading the version from client 000, including the extra blank lines that you created in Figure 5, as shown in Figure 12. The system now looks through to client 000 and sees the version with the blank lines because you just deleted the copy from client 100.

If you delete lines 20 and 30 in client 000, the changes will be available in your development client (100) (Figure 13). Now that your local version has been deleted, your system identifies any changes and looks into client 000 from client 100.

Figure 13
Changes in client 000 are now reflected in client 100
If you did try to delete a standard schema which hadn’t been modified, you receive the error message A standard schema cannot be deleted in the status bar of your screen. Performance Assistant provides a diagnosis of the error message, explaining that you can only delete customer or modified schemas; not standard SAP schemas.
Now that your SAP standard schemas are up to date, you can be positive that the versions you are using in your local client will always reflect the SAP standard version of your HR SP. Rest assured that whether you use a standard SAP schema in your user-specific schemas or you use it as a reference for your own developments, you are working with an up-to-date version.
Ian Moogan
Ian Moogan has 15 years of SAP R/3 experience, covering configuration, ABAP, and Basis. For the past two years, he has worked as a consultant for ROC, providing HR and Payroll support to many clients in a variety of industries.
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