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Website Penetration Testing

Introduction to SQL Database

What is a database?

A database is an area to store data.

A RDBS(Relational database system) stores data in tables.

What is SQL?

SQL is a language used in RDMS to retrieve and manipulate data.

SQL is for the structured query language.

SQL is the structured query language, a computer language for storing, manipulating, and retrieving data stored in a relational database.

SQL is the standard language for (relational database systems) RDBS. All RDBMS such as MySQL, Oracle, Sybase, Informix, Postgres, and SQL attendants use SQL as their standard database language.

Also, they are using different commands, such as -

MS SQL Server using T-SQL,

PL / SQL, using Oracle

The MS Access version of SQL is called JET SQL (native format) etc.

SQL applications-

As mentioned earlier, SQL is one of the most commonly used query languages on databases. I am going to list some of them here:

It allows users to access data in a relational database management system.

It allows users to describe data.

It allows users to define data in the database and manipulate that data.

Allows embedding within other languages using SQL factor, libraries, and pre-compilers.

Allows users to create and drop dB(database) and tables.

It allows users to create views, stored procedures, functions in the database.

It allows users to set acceptance on tables, processes, and views.

SQL process-

When you are executing the SQL command for any RDBMS, the system determines the best way to interpret the task to complete your request and the statistics of the SQL engine.

Various components are involved in this process.

These components are -

Query dispatcher

Optimization engine

Classic query engine

SQL Query Engine, etc.

SQL commands-

The SQL commands for interacting with relational databases(RDBS) are SELECT, INSERT, UPDATE, DELETE, and DROP. These orders can be classified into the following groups based on their nature -

DDL - Data Definition Language

1.CREATE - Creates a new table, a view of the table or another object in the database.

2.ALTER — Modifies an actual database object, such as a table.

3.DROP - Removes the entire table, the view of the table or other objects in the database.

DML - Data Manipulation Language

1.SELECT — Gets some records from one or more tables.

2.INSERT - Creates a record.

3. Update — Modifies the record.

4.DELETE-Deletes Record.

DCL - Data Control Language

1. gives digital-user a privilege.

2.REVOKE — Revokes the privileges received from the user.