Field Catalog for Condition Keys 
Definition
The field catalog contains all fields that can be selected as keys for Message Control condition tables. One application filter per application is created from this field catalog. This filter determines which fields can be selected for the relevant application (for example V1 for "Sales").
Use
Defining the condition table
When
creating a condition table you select the key fields from the "application filtered" field catalog which should be used in message determination for table access.Defining the application filter
In order to define or extend the application filter, maintain Customizing table T681F: Use, for example, transaction NACE (expert mode) and choose Edit ® Field Catalog. Select new fields from the
communication structures for your application.Extend field catalog
If you want to define a condition field for your application that does not yet exist in the field catalog, then before generation of the condition tables or the access sequences you must extend the field catalog (valid for all applications).
The field catalog for the message determination has the structure KOMB. This name is stored in table T681V. The uses of the condition technique (pricing, message determination, etc.) and their attributes are managed here. Every use of the condition technique has its own field catalog.