SQL is the language for working with a database that includes many operations such as creating databases, deleting data, extracting data, modifying data, etc. In this series of articles, we will Learn the basics of SQL, create tables, queries, clauses, … You keep track of it.

What is SQL?

Overview of SQL

Overview of SQL

SQL, short for Structured Query Language, is a structured query language that allows you to access and manipulate databases to create, delete, modify, extract data.

SQL is also the standard language for relational database systems.All database management systems (RDBMS) such as MySQL, MS Access, Oracle, Sybase, Informix, Postgres, or SQL Server all use SQL as the standard database language.

If you learn about SQL Server from Microsoft, you will know that in addition to SQL, this database system uses T-SQL as a “local” language. Oracle SQL uses PL / SQL, …

SQL has been around since the 1970s.Edgar F. “Ted” Codd of IBM describes a relational model for databases.In 1974, SQL began to appear.Four years later, IBM developed Codd’s ideas and created a product called System / R.In 1986, IBM developed the first prototype of the relational database and was standardized by ANSI.The first relational database was released by Relational Software (now Oracle).

What can SQL do?

SQL brings many benefits, such as:

  • Create a new database
  • Create a new table in the database
  • Create a new view
  • Execute the query on the database
  • Describe the data
  • Create, insert, delete, modify records in the database
  • Extract data from the database
  • Set permissions on the table, procedure, and view
  • Embedding other languages using the SQL module, library, compiler available

How are SQL statements executed?

When you execute aSQL statementon any relational database administrator, the system decides the best way to execute that command, and the SQL engine will help you understand the task being interpreted. any.

There are many components in this process: Query Dispatcher, Optimization Engines, Classic Query Engine, SQL Query Engine.

SQL statements

Overview of SQL

Overview of SQL

Here are some basic commands (classified by the nature of the command) of SQL:

DDL – Data Definition Language

  • CREATE: Create a new table, view of the table and other objects in the database.
  • ALTER: Edit existing data objects, like tables.
  • DROP: Deletes the entire table, table view, or other objects in the database.

DML – Data Manipulation Language (Language to manipulate data)

  • SELECT: Extract a specific record from one or more tables
  • INSERT: Insert new data into the database.
  • UPDATE: Modify, update the data in the database.
  • DELETE: Deletes data from the database.

DCL – Data Control Language

  • GRANT: Grant privileges to the user
  • REVOKE: Get the permissions granted to the user

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Here, you know the basics of SQL, the basic SQL statements, and the functionality of those commands.In the next article, we will learn about RDBMS, data elements in relational database, and so on.