In most cases, the default mapping mechanism that pairs the objects based on their name, is what is needed. There are however scenarios on which tables, for example, on the development database may have names prefixed with dev_ whereas the same tables in the production database do not have that prefix. In such cases you may want to define certain mapping rules that would allow you to pair objects that would otherwise not be paired together by simple name-matching rule.
The Mapping Rules can be accessed from the ribbon or from the action links on the right panel of the comparison tab. By default data compare performs an exact match on the object names. However, you can choose to ignore certain prefix or postfix. If you ignore, for example, the "dev_" prefix on the source tables and the "prod_" prefix on the target tables, a table named dev_employees on the source schema will be mapped to a table named prod_employees on the target schema.
