dbms (3436737839399388838388383860).pptx
- 1. DBMS Languages By B.Sai Santhosh Reddy MCA first year Roll.no 30 Hall ticket no.2303B09930 DBMS
- 2. DBMS Languages: • A DBMS has appropriate languages to express database queries and updates. • Database languages can be used to read, store and update the data in the database.
- 3. Data Definition Language: • DDLstandsfor Data Definition Language. It is used to define database structure or pattern. • It is used to create schema, tables, indexes, constraints, etc. in the database. • Using the DDL statements, you can create the skeleton of the database. • DDL is used to store the information of metadata like the number of tables and schemas, their names, indexes, columns in each table, constraints, etc.
- 4. Here are some tasks that come under DDL: • Create: It is used to create objects in the database. • Alter: It is used to alter the structure of the database. • Drop: It is used to delete objects from the database. • Truncate: It is used to remove all records from a table. • Rename: It is used to rename an object.
- 5. Data Manipulation Language: • DML stands for Data Manipulation Language. It is used for accessing and manipulating data in a database. It handles user requests. • The DDL and DML are collectively referred to as the data sublanguage when embedded within a host language (Ex: C or COBOL)
- 6. Here are some tasks that come under DML: • Select: It is used to retrieve data from a database. • Insert: It is used to insert data into a table. • Update: It is used to update existing data within a table. • Delete: It is used to delete all records from a table.
- 7. Data Control Language • DCL stands for Data Control Language. It is used to retrieve the stored or saved data. • The DCL execution is transactional. It also has rollback parameters. Here are some tasks that come under DCL: • Grant: It is used to give user access privileges to a database. • Revoke: It is used to take back permissions from the user.
- 8. Transaction Control Language: • TCL is used to run the changes made by the DML statement. TCL can be grouped into a logical transaction. Here are some tasks that come under TCL: • Commit: It is used to save the transaction on the database. • Rollback: It is used to restore the database to original since the last Commit.