• Insertion anomalies
– We tried to insert data in a record that does not exist at
all.
• Deletion anomalies
– We tried to delete a record, but parts of it was left
undeleted because of unawareness, the data is also
saved somewhere else.
• Modification anomalies
– If data items are scattered and are not linked to each
other properly, then it could lead to strange situations.
• For example, when we try to update one data item having its
copies scattered over several places, a few instances get
updated properly while a few others are left with old values.
Such instances leave the database in an inconsistent state.