If somehow, the correct address gets updated in one department but not in other then as per the database, Rick would be having two different addresses, which is not correct and would lead to inconsistent data. If we want to update the address of Rick then we have to update the same in two rows or the data will become inconsistent. Update anomaly: In the above table we have two rows for employee Rick as he belongs to two departments of the company.

We will see the problems that we face when a table is not normalized. At some point of time the table looks like this: emp_id Let’s take an example to understand this.Įxample: Suppose a manufacturing company stores the employee details in a table named employee that has four attributes: emp_id for storing employee’s id, emp_name for storing employee’s name, emp_address for storing employee’s address and emp_dept for storing the department details in which the employee works. These are – Insertion, update and deletion anomaly. There are three types of anomalies that occur when the database is not normalized. Let’s discuss about anomalies first then we will discuss normal forms with examples. Normalization is a process of organizing the data in database to avoid data redundancy, insertion anomaly, update anomaly & deletion anomaly.

What is anomaly in database