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Difference Between DDL and DML in DBMS

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DDL is a Data Definition Language that is used to define data structures. For example: creating a table, and altering a table are instructions in SQL. DML is a Data Manipulation Language that is used to manipulate data itself. For example: insert, update, and delete are instructions in SQL.

Data Definition Language

  • DDL is used to specify a database’s structure, which includes its tables, views, indexes, and constraints.
  • DDL commands come in the following types: CREATE, ALTER, DROP, RENAME, and TRUNCATE.
  • DDL statements only modify the database’s schema; they have no direct effect on the data within the database.
  • DDL declarations are irreversible and difficult to undo.

Data Manipulation Language

  • Inserting, updating, removing, and retrieving data from a database are all possible with DML.
  • DML commands come in the following types: SELECT, INSERT, UPDATE, DELETE, and MERGE.
  • DML statements have a direct impact on the database’s data.
  • In the event of an error, data can be recovered thanks to the reversibility of DML statements.

Difference Between DDL and DML

DDL DML
It stands for Data Definition Language. It stands for Data Manipulation Language.
It is used to create database schema and can be used to define some constraints as well. It is used to add, retrieve, or update the data.
It basically defines the column (Attributes) of the table. It adds or updates the row of the table. These rows are called tuples.
It doesn’t have any further classification. It is further classified into Procedural and Non-Procedural DML.
Basic commands present in DDL are CREATE, DROP, RENAME, ALTER, etc. BASIC commands present in DML are UPDATE, INSERT, MERGE etc.
DDL does not use WHERE clause in its statement. While DML uses WHERE clause in its statement.
DDL is used to define the structure of a database. DML is used to manipulate the data within the database.
DDL is used to create and modify database objects like tables, indexes, views, and constraints. DML is used to perform operations on the data within those database objects.
DDL statements are typically executed less frequently than DML statement DML statements are frequently executed to manipulate and query data.
DDL statements are typically executed by database administrators. DML statements are typically executed by application developers or end-users.
DDL statements are not used to manipulate data directly. DML statements are used to manipulate data directly.
The database’s contents are not altered by DDL commands. DML commands alter the database’s contents.
Examples of DDL commands: CREATE TABLE, ALTER TABLE, DROP TABLE, TRUNCATE TABLE, and RENAME TABLE. Examples of DML commands: SELECT, INSERT, UPDATE, DELETE, and MERGE.

Conclusion

The database structure is shaped using DDL (Data Definition Language) commands such as CREATE and ALTER, which immediately commit permanent changes. On the other hand, explicit transaction control is necessary when using DML (Data Manipulation Language) to handle data through operations like SELECT and UPDATE. Each plays a vital function in Database Management Systems: DML manipulates data, whereas DDL defines the database.


Last Updated : 22 Nov, 2023
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