Data Dictionary in DBMS

DBMSDatabaseMySQL

Data Dictionary consists of database metadata. It has records about objects in the database.

What Data Dictionary consists of

Data Dictionary consists of the following information −

  • Name of the tables in the database
  • Constraints of a table i.e. keys, relationships, etc.
  • Columns of the tables that related to each other
  • Owner of the table
  • Last accessed information of the object
  • Last updated information of the object

An example of Data Dictionary can be personal details of a student −

Example

<StudentPersonalDetails>

Student_ID
Student_Name
Student_Address
Student_City


The following is the data dictionary for the above fields −

Types of Data Dictionary

Here are the two types of data dictionary −

Active Data Dictionary

The DBMS software manages the active data dictionary automatically. The modification is an automatic task and most RDBMS has active data dictionary. It is also known as integrated data dictionary.

Passive Data Dictionary

Managed by the users and is modified manually when the database structure change. Also known as non-integrated data dictionary.

raja
Published on 03-Jul-2018 20:35:01
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