DDL in DBMS vs. DML in DBMS: What's the Difference?
Edited by Aimie Carlson || By Janet White || Published on February 29, 2024
DDL (Data Definition Language) in DBMS is used for defining database structures, while DML (Data Manipulation Language) is used for managing data within those structures.
Key Differences
DDL in DBMS, or Data Definition Language, is used for defining and modifying database structures like tables, schemas, and indexes. DML, Data Manipulation Language, on the other hand, is utilized for inserting, updating, deleting, and retrieving data from the database.
Operations performed using DDL directly affect the database schema and its architecture. In contrast, DML operations impact the data within the tables but do not alter the schema itself.
DDL includes commands like CREATE, ALTER, and DROP, which are used to create, modify, and delete database structures. DML encompasses commands such as SELECT, INSERT, UPDATE, and DELETE, which are used for data handling within the database.
Generally, DDL commands are auto-committed, meaning they save changes permanently to the database. DML commands, however, can be rolled back or undone if they are part of a transaction that has not been committed yet.
DDL is used during the initial setup and for subsequent modifications of the database structure. DML is used in routine operations for managing and manipulating data within the existing database structures.
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Comparison Chart
Purpose
Defines and modifies database structures
Manages data within database structures
Impact
Alters database schema
Modifies data, not schema
Commands
CREATE, ALTER, DROP
SELECT, INSERT, UPDATE, DELETE
Transaction Control
Auto-committed operations
Can be part of transactions and rolled back
Usage
Used for setup and structural modifications
Used for routine data management and queries
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DDL in DBMS and DML in DBMS Definitions
DDL in DBMS
Index Creation.
Using DDL, the CREATE INDEX command creates an index on a table column.
DML in DBMS
Data Retrieval.
DML is used to fetch specific data with the SELECT query.
DDL in DBMS
Schema Modification.
ALTER TABLE in DDL is used to add a new column to an existing table.
DML in DBMS
Data Insertion.
The INSERT INTO statement in DML adds new records to a table.
DDL in DBMS
Database Object Removal.
The DROP TABLE command in DDL removes an existing table from the database.
DML in DBMS
Data Deletion.
DELETE FROM in DML removes records from a table.
DDL in DBMS
Database Structure Definition.
The CREATE TABLE statement in DDL defines a new database table.
DML in DBMS
Data Query.
SELECT in DML is used to retrieve data from the database.
DDL in DBMS
Table Alteration.
DDL's ALTER TABLE command modifies the structure of an existing table.
DML in DBMS
Data Update.
The UPDATE statement in DML modifies existing data in a table.
FAQs
Can DDL commands roll back?
Generally, DDL commands are auto-committed and cannot be rolled back.
Can DML commands be undone?
Yes, if they are part of an uncommitted transaction.
What is DDL in DBMS?
DDL, Data Definition Language, is used for defining and modifying database structures.
What does DML stand for in DBMS?
DML stands for Data Manipulation Language, managing data within database structures.
Is DML used for creating tables?
No, DML is used for managing data, not for creating tables.
What is an example of a DDL command?
An example is CREATE TABLE, which creates a new table.
What does the ALTER command do?
ALTER, a DDL command, modifies the structure of an existing database object.
How does DML interact with data?
DML interacts by inserting, updating, deleting, and retrieving data.
Can DDL define relationships between tables?
Yes, DDL can define relationships like foreign keys.
Are indexes created using DDL?
Yes, indexes are created using DDL commands like CREATE INDEX.
Is the DELETE command DDL or DML?
DELETE is a DML command used to remove data.
Is SELECT a DML command?
Yes, SELECT is used in DML to query data.
Can DML commands affect database schema?
No, DML commands do not change the database schema.
Can DML statements create new database objects?
No, that is the function of DDL.
Does DML have any role in database design?
DML doesn't design databases but operates within the designed structures.
Can DML modify the data type of a column?
No, modifying data types is a function of DDL.
How often is DML used compared to DDL?
DML is used more frequently for regular data manipulation.
What's the difference in usage between DDL and DML?
DDL is used for structural setup and modifications, DML for data operations.
Do DDL operations require a commit?
DDL operations are usually auto-committed.
Is ALTER TABLE a DDL command?
Yes, it's used to modify table structures.
About Author
Written by
Janet WhiteJanet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie CarlsonAimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.
