#What is anomaly in database update

It should only have single(atomic) valued attributes/columns.Normalization rules are divided into the following normal forms:ДЇor a table to be in the First Normal Form, it should follow the following 4 rules: Hence, at the end of the academic year, if student records are deleted, we will also lose the branch information. In our Student table, two different informations are kept together, Student information and Branch information. X leaves the college? or is no longer the HOD of computer science department? In that case all the student records will have to be updated, and if by mistake we miss any record, it will lead to data inconsistency. These scenarios are nothing but Insertion anomalies.

Suppose for a new admission, until and unless a student opts for a branch, data of the student cannot be inserted, or else we will have to set the branch information as NULL.ДЄlso, if we have to insert data of 100 students of same branch, then the branch information will be repeated for all those 100 students. As we can see, data for the fields branch, hod(Head of Department) and office_tel is repeated for the students who are in the same branch in the college, this is Data Redundancy.

In the table above, we have data of 4 Computer Sci. To understand these anomalies let us take an example of a Student table. Insertion, Updation and Deletion Anomalies are very frequent if database is not normalized.

#What is anomaly in database update

If a table is not properly normalized and have data redundancy then it will not only eat up extra memory space but will also make it difficult to handle and update the database, without facing data loss. If you want you can skip the video, as the concept is covered in detail, below the video. The video below will give you a good overview of Database Normalization. Ensuring data dependencies make sense i.e data is logically stored.Normalization is used for mainly two purposes, It is a multi-step process that puts data into tabular form, removing duplicated data from the relation tables. Normalization is a systematic approach of decomposing tables to eliminate data redundancy(repetition) and undesirable characteristics like Insertion, Update and Deletion Anomalies. ER Model: Generalization and SpecializationДatabase Normalization is a technique of organizing the data in the database.