If a database design is not perfect, it may contain anomalies, which are like a nightmare for any database administrator. Managing a database with
anomalies is next to impossible.There are different types of anomalies which can occur in referencing and referenced relation which can be discussed as:
Insertion anomaly
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.
Update 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.
Normalization is a method to remove all these anomalies and bring the database to a consistent state.
anomalies is next to impossible.There are different types of anomalies which can occur in referencing and referenced relation which can be discussed as:
Insertion anomaly
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.
Update 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.
Normalization is a method to remove all these anomalies and bring the database to a consistent state.
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