The list in the Delete Information section on the JoinDef Update & Delete Rules frame contains one row for each table in the JoinDef. This row specifies its type (master or detail), table name or abbreviation, and whether or not rows can be deleted from that table. Again, only the Delete list can be modified. Move the cursor to the entry and type the new value. Changing Yes to No specifies that rows cannot be deleted from that table. Menu choices during query execution change to fit the rules you have specified.