Question

1. What is SQL ? What are the different categories of SQL commands?​

Answer 1

Answer:

Explanation:

SQL stand for Structured Query Language. SQL is a domain-specific language used in programming and designed for managing data held in a relational database management system, or for stream processing in a relational data stream management system.

SQL Commands categorized in four

1 - DDL

2- DQI

3- DML

4- DCL

Answer 2

Answer:

What is SQL?

SQL or Structured Query Language is a standard language used for communicating with databases. It is a language for storing, retrieving, and manipulating data in a database. Different Relational Database Management Systems (RDBMS) like MySQL, Oracle, Postgres, SQL Server, etc. are using SQL as a language for manipulating databases.

SQL Commands:

SQL language uses different commands to manipulate data in the databases. SQL commands are of four types: DDL, DML, DCL, and TCL.

i) DDL (Data Definition Language)

DDL stands for Data Definition Language. DDL Commands are used to structure the tables like creating tables, deleting tables, altering a table, etc.

Commands in DDL:

• CREATE – Used to create a new table in the database.
• ALTER – Used to change the structure of a table like adding or modifying attributes in a table.
• DROP – Used to delete an existing table in a database.
• TRUNCATE – Used to delete all the rows in a table.

ii) DML (Data Manipulation Language)

DML stands for Data Manipulation Language. DML Commands are used to manipulate the data in a table in a database.

Commands in DML:

• INSERT – Used to insert data into a table.
• SELECT – Used to select data from a database.
• UPDATE – Used to modify the data in a table.
• DELETE – Used to delete a row from a table.

iii) DCL (Data Control Language)

DCL stands for Data Control Language. DCL Commands are used to grant and take back the authority from a database user.

Commands in DCL:

• GRANT – Used to give access privileges to users to a database.
• REVOKE – Used to take back the permission from the user.

iv) TCL (Transaction Control Language)

TCL stands for Transaction Control Language. TCL commands can only be used with INSERT, DELETE and UPDATE commands.

Commands in TCL:

• COMMIT – Used to save all the transactions in a database.
• ROLLBACK – Used to undo the transactions that had not been saved to the database.

Explanation:

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