Referential integrity must be maintained between all dimension tables and the fact table. Each fact record contains foreign keys that relate to primary keys in the dimension tables. Every fact record must have a related record in every dimension table used with that fact table. Missing records in a dimension table can cause facts to be ignored when the dimension table is joined to the fact table to respond to queries or for the population of OLAP cubes. Queries can return inconsistent results if records are missing in one or more dimension tables. Queries that join a defective dimension table to the fact table will exclude facts whereas queries that do not join the defective dimension table will include those facts.