Standard Database Tables and Structures defined by SAP within the ABAP Data Dictionary can be enhanced by customers using Custom includes or append structures. The table enhancement category provides a way of limiting this customization so that dependent objects are not negatively affected. You, therefore, need to understand how this works before you are able to enhance a table correctly.
For this reason, you must select an enhancement category when you create a new SAP table. Also within ABAP programs without an active Unicode check, table and structure enhancements can cause syntax/runtime errors during type checks, particularly if they contain deep structures.
In programs where there is an active Unicode check, statements, operand checks, and use of offset and length are problematic. For example, if numeric or deep components are inserted into a purely character-type structure it would lose its character type nature.
Depending on the definition of the structure, the enhancement categories available within your SAP system are as follows:
If you don’t choose an enhancement category you get the warning “Enhancement category for table missing” when you try to activate it. It is only a warning so you could just ignore it but this is not recommended.
To help you decide which enhancement category an object should be there are a number of rules for defining it implicitly, based on the structures set up and the classification of the types used. These are as follows:
When creating new tables and structures within the ABAP Dictionary the SAP system will propose “Can be enhanced (deep)” as the default value. If you choose a more restrictive category for a particular structure, then only the classification levels that adhere to the rules above are allowed.
It is not possible to choose an enhancement classification that is more restrictive than that resulting implicitly from the structure set up and from the classification of the types used. Only the allowed categories will be proposed for selection in the maintenance user interface.
If a structure depends on one or several other structures, the most restrictive category is chosen as implicit classification.
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