Database Management Systems or DBMS are software that allows users to create and manage databases. In DBMS, there are two types of languages that are used, Data Definition Language (DDL) and Data Manipulation Language (DML). Both the languages, though different in nature, play an important role in creating and maintaining a database. In this article, we’ll dive into the differences between DDL and DML.
Data Definition Language (DDL):
DDL is a set of commands that define the structure of the database. It provides a way to define and manage the schema (structure) of the database. The schema defines the tables, relationship and constraints that exist in the database. DDL commands enable developers to create, modify or delete database objects, such as tables, views, indexes, synonyms, stored procedures, and more. Here are some of the DDL commands used in DBMS:
The Create command is used to create a new database object such as a table, index, view, or stored procedure.
The Alter command is used to alter the structure of the database object.
The Drop command is used to delete a table, view, index, or any other database object.
The Truncate command is used to erase all the data that exists in a table.
The Rename command is used to rename a database object.
Data Manipulation Language (DML):
DML is a set of commands that help to manage the data stored in the database. It is used to insert, update, delete, select or manipulate data in the database. These commands help developers to perform operations such as inserting a new record, updating an existing record, deleting a record, or selecting the data from one or more tables. Here are some of the DML commands used in DBMS:
The Select command is used to retrieve data from the database.
The Insert command is used to insert new data into the database.
The Update command is used to update existing data in the database.
The Delete command is used to delete data from the database.
Difference between DDL and DML:
1. Scope of Operation:
The main difference between DDL and DML is the scope of the operation. DDL is used to define the structure of the database, while DML is used to manipulate the data stored in the database.
2. Operation Performed:
DDL commands deal with altering the schema of the database, whereas DML commands deal with inserting, updating, and deleting data in the database.
DDL operations have a more significant impact on the database than DML operations. When a DDL command is executed, it affects the complete structure of the database. On the other hand, DML operations only affect specific rows or records.
4. Transaction Control:
DDL operations cannot be rolled back once they are executed, while DML operations can be rolled back, making them more flexible.
DDL commands require higher privileges than DML commands. Typically, only database administrators or other privileged users can execute DDL commands, while other users with limited privileges can execute DML commands.
In conclusion, DDL and DML are an integral part of Database Management Systems. DDL is used to create and modify the schema of the database, while DML is used to manage the data in the database. They have different roles to play and require distinct commands to implement them. Understanding the difference between DDL and DML is crucial to ensure proper database management and an efficient database.