Insertion Anomalies
Case I: When a record of a fact is inserted into a table, it also requires inserting the detail of another fact.
Case II: Information of another fact is needed before the detail of a fact can be inserted into a table. Otherwise, a null value have to be used for the needed fact.
Deletion Anomalies
When there is a record removed from a table, some valid fact is lost.
Modification Anomalies
When there is an occurrence of a fact changed, not all related occurrences are changed.