What is SQL

 

What Is SQL?

SQL is a structured query language. It was developed by IBM (international business Machine). It is endorsed as a national standard by the American national standard institute. It is the language that is used frequently for relational data models. SQL works with database programs like MS Access, DB2, Informix, Oracle, MS SQL Server, Sybase.

What is SQL used for:

SQL is used for extracting data from the database. Now, what is the database? A database is a large collection of data that is organized in a good manner way so that the user can access data efficiently and that data is stored in a compact(taking less space) manner on a computer. when we talk about Database here is another term used parallelly with it which is DBMS. Database Management System(DBMS) is a program that is used to create and maintain the data of the database. Let’s suppose we have a database “Employee” that contain the information of all employees who work in an organization like their Id, Name, Department, E_mail, etc to handle this data and apply different constraints(rules) there must be a system which is called DBMS. The constraint can be data type like name column must have alphabetic data or E_mail must have @ sign etc. To summarize users can interact with the database through DBMS.



 So SQL is a language through which one can drive the data from the database and data can also be filtered by applying different queries. A query is a question that can be asked for retrieving particular data from the database. Suppose there is a database named “STUDENT” that can have attributes Roll_no, Std_name, Address and class. If you want to filter those students who are residents of city “California” then you can perform this operation through SQL statements easily instead of performing that operation manually which is a long as well as time-consuming process at all.

SQL Is  A  Data Sublanguage:

SQL is not a full-featured programming language like other languages like C++, C#, JAVA, etc .It is a data sublanguage. It means that it has only language statements data definition and Processing (Querying and updating). Data definition commands are called DDL Like creating a table and its structure(no of rows and columns). The data query and updating commands (e.g insert delete a particular data) are called Data Manipulation Language DML.

Objective Of SQL :

This Database Language allows the user to:

Ø  👉Create the database and relation ( another term used for table) structures.

Ø  👉Perform basic database management tasks such as insertion-deletion and modification of data in tables.

Ø 👉 Perform both simple and complex (join queries: retrieve data from multiple tables) queries.

Ø  👉SQL can perform operations and filter data from a set of records (rows) instead of a single record.

Ø  👉User can write the SQL statements without keeping in mind the casing because t is not a case sensitive language.

Ø  👉SQL provides the high level of security on data as the data of  tables can be protected by applying different checks on incoming and outgoing data Moreover data can be secured by applying a password on table level.

Ø  👉SQL is a flexible language as new data can be easily inserted and nonuse data can be deleted. 

So we can conclude that SQL is a language that is specifically built for the Relational database model used for extracting data from relations(tables). It has two sublanguages DDL and DML.

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