Data Integrity in DBMS

The Reliability and accuracy of data is called the data integrity.

Types of Data Integrity in DBMS:

1. Entity integrity
2. Domain integrity
3. Referential integrity
4. User defined integrity

1. Entity Integrity:

The basic idea of entity integrity is that each should have acolumn that uniquely identifies the remaining columns in the table.

2. Domain Integrity:

It refers to the range of values that are allowed for the column.

3. Referential Integrity:

It refers to the relationships between the columns of a table.

4. User Defined Integrity:

It allows the user or administrator to enforce the new business rules which does not falls under above integrity.

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Dependencies In DBMS

Before discussing about the dependencies let us know what is meant by Entity and Attribute.

Entity: It is a person, place, event or thing about which the information is mentioned. For example employee, customer, student are called entities.

Attribute:The characteristic property that describes an entity is called attribute. For example emp number of employee or customer id of customer entity.

Three type of dependencies in DBMS

1. Functional Dependency
2. Partial Functional Dependency
3. Transitive Dependency.

Database Models in DBMS

DBMS: Database Management System

DBMS

• It is a collection of interrelated data and set of programs to access the data from database.
• It is a suit of software programs for creating maintaining the data in the database.
• Users are connected with DBMS not with the data.
• It allows the organisation to store data in one location from which multiple users can access the data.
• user can insert, update, delete the data by using tools provided by DBMS.

Normalization in Database

Normalization is the process of decomposing the relations (Tables) into smaller and well structured relations, to avoid the data redundancy. (or)

Normalization is the process of deciding which attributes should be grouped in a table to avoid the data redundancy in database.

There are some rules in the normalization each rule is called a normal form.

1. First Normal form (1NF)
2. Second Normal form (2NF)

3. Third Normal form (3NF)
4. Fourth Normal form (4NF)
5. Fifth Normal form (5NF).