The names of exact-match columns cannot be longer than 26 characters.

Exact-match columns must be of type VARCHAR or CHAR.

Match columns can be used to match on any text column or combination of text columns from a base object.

If you want to use numerics or dates, you must convert them to VARCHAR using cleanse functions before they are loaded into your base object.

Match columns can also be used to match on a column from a child base object, which in turn can be based on any text column or combination of text columns in the child base object. Matching on the match columns of a child base object is called intertable matching.

When using intertable match and creating match rules for the child table (via a foreign key), you must include the foreign key from the parent table in each match rule on the child. If you do not, when the child is merged, the parent records would lose the child records that had previously belonged to them.