INTRODUCTION TO SQL AND SQL TOOL

INTRODUCTION TO SQL AND SQL TOOL

 Introduction

We will learn about SQL and SQL Commands in this tutorial.

SQL

Structured Query Language is known as SQL. In a database management system, SQL is used to build, remove, modify databases and database objects as well as to store, retrieve, and update data in databases. A database management system can be created, accessed, and modified using the standard language SQL. All current relational database management systems, including SQL Server, Oracle, MySQL, etc., support SQL.

various SQL command types

Based on their functionality, SQL commands can be divided into five groups.

DDL

Data description language is what it stands for. In the relational database management system, DDL operations like CREATE DATABASE, CREATE TABLE, ALTER TABLE, etc. are used to create and modify databases and database objects. The DDL commands CREATE, DROP, ALTER, and TRUNCATE are the most often used.

CREATE

A database and database objects like a table, index, view, trigger, stored procedure, etc. are created using the CREATE command.

Syntax

Create the table "Employee" with the columns "Id INT, Name VARHCAR(50), and Address VARCHAR(100)"

ALTER

The database object and database settings can be reorganised using the ALTER command.

Syntax

employee table changed with salary included in;

TRUNCATE

The table's whole contents can be deleted using the TRUNCATE command. The command TRUNCATE clears a table.

Syntax

Employee: TRUNCATE TABLE;

DROP

To delete the database and database object, use the DROP command.

Syntax

Employee of DROP TABLE;

 DML

Data manipulation language is what it stands for. Data manipulation in a relational database management system is done using DML commands. DML instructions, such as INSERT INTO TableName, DELETE FROM TableName, UPDATE tableName set data, etc., are used to add, remove, and update data in the database system. The most often used DML commands are UPDATE, DELETE FROM, and INSERT INTO.

PLACE INTO

In order to add data to a database table, use the INSERT INTO command.

Syntax

Enter "Arvind Singh," "Pune," and "1000" into the employee's (Id, Name, Address, Salary) values field.

UPDATE

To update data in a database table, use the UPDATE command. To update a particular row, a condition can be introduced using the WHERE clause.

Syntax

Employee: UPDATE Employee SET Address to "Pune, India," Salary to "100," and Id to "1";

DELETE

Data can be deleted from a database table using the DELETE command. The WHERE clause can be used to add a condition to get rid of a certain row that matches it.

Syntax

Id = 1; DELETE FROM Employee WHERE

Delete

Data can be deleted from a database table using the DELETE command. The WHERE clause can be used to add a condition to get rid of a certain row that matches it.

Syntax

WHERE Id = 1, DELETE FROM Employee;

DQL

The letters DQL stand for data query language. The data is fetched using the DQL command. Data can be chosen from a table, view, temporary table, table variable, etc. using the DQL command. Under DQL, the SELECT command is the sole available command.

Syntax

SEARCH FOR * IN Employee;

DCL

Data control language is referred to as DCL. Access privileges to databases and database objects are granted and revoked using DCL commands. The DCL command is used to limit user access to the data. GRANT is one of the top DCL commands utilised.

GRANT

GRANT is a tool used to grant users access rights.

COM MIT

The database modification is saved or applied using the COMMIT command.

ROLLBACK

The modification can be reversed using the ROLLBACK command.

SAVEPOINT

A transaction can be momentarily saved using the SAVEPOINT command and then rolled back to this point if necessary.

Syntax

merely scribble out COMMIT, ROLLBACK, or SAVEPOINT;

Summary

We learned about SQL and SQL commands in this article.

Syntax

Grant Employee INSERT, DELETE ON User;

REVOKE

The REVOKE command cancels the user's access rights to the database object and is used to revoke such rights.

Syntax

REVOKE ALL ON USER FOR Employee;

TCL

Transaction Control Language is referred to as TCL. For managing transactions in the database, TCL commands are utilised. Data integrity in a multi-user environment is ensured by transactions. Data modification in the database can be committed and rolled back using TCL commands. The TCL commands COMMIT, ROLLBACK, SAVEPOINT, and SET TRANSACTION are the most often used.