Column groups and priority groups provide interfaces to a variety of built-in conflict resolution techniques and the easiest way to configure your application to resolve conflicts automatically. Let’s look at them one at a time.
A column group is a set of one or more columns associated with a single conflict resolution method. A column cannot belong to more than one column group, and columns that are not explicitly assigned to a column group are members of a shadow column group, which Oracle creates by default and which uses the default conflict resolution methods.
For example, suppose that you want to define a column group for the EMPLOYEES table described in the following table:
Use the procedure DBMS_REPCAT.MAKE_COLUMN_GROUP to define a column group for fields that the personnel site maintains (i.e., LAST_NAME, FIRST_NAME, SOCIAL_SECURITY_NO, MARITAL_STATUS, HOME_PHONE). The application records information about changes to these fields in PERS_GLOBAL_NAME and PERS_TIMESTAMP.
EXECUTE dbms_repcat.make_column_group( - gname => 'HR', - oname => 'EMPLOYEES', - column_group => 'CG_EMP_PERSONNEL', - list_of_column_names => ...