Introduction of SQL, Features, Data Types


Introduction of SQL-

SQL means Structured Query Language, The SQL software used for database handling like data insert into database, Update from database, Delete from database also we alter table with use of SQL. The SQL also called S-Q-L or sometime See-Qwell. The SQL  uses a relational database system for data accessing and fetching mainly. They also describing data in well manner. The data manipulation handling well in manner for data operations. The SQL fallows the different queries for data manipulation. The SQL  also helps to user for creating view to user for data displaying data with different angle. The SQL  also provide a well security to user for database.

History of SQL-

  1. 1970 – The Dr. Edgar F. “Ted” Codd create a relational model for different database.
  2. 1978 – The IBM develop and releases System/R.
  3. 1989 – In 1989 the First version of SQL launched.
  4. 1999 -The  SQL 3 launched with different functionalities.
  5. SQL 2003 -That version provide window functions, XML-related features for data manipulation.
  6. SQL 2006 –  XML Query Language version.
  7. SQL 2011 -Importing system version of database can be launched.

Features of SQL-

  1. The SQL provide different functionality to user for data manipulation task.
  2. SQL is scalable and maintain integrity of data.
  3. They provide Data Manipulation Language(DML), Data Definition Language(DDL), Data Control Language(DCL), Transaction Control Language(TCL), Data Query Language(DQL) commands for data operations.
  4. Complex calculations perform well in manner on SQL platform.
  5. The security of data strongly bound with user at the time of database accessing.
  6. That functionality support to ‘view’ that reason user can extract data from different point.

SQL Data Types-

The all data can be saved with use of data types mainly. In SQL mainly 3 types of data types are occurred for data saved successively. The 3 types of data types as fallows-

  1. String Data Type
  2. Numeric Data Type
  3. Date and Time saving Data Types mainly.
  1. String Data Type-

In that data types string or text data was saved for further manipulations. Like-Char, Varchar, Binary, Varbinary, Text, Longtext etc

2. Numeric Data Type- In that store numeric ,integer values only. Like-Int, Float, Double, Decimal, Bool etc.

3. Date and Time-In that store date and time data from user mainly. Like-Datetime, Date, Time, Year etc.

SQL Commands-

  1. Data Definition Language(DDL)-Create, Drop, Alter, Truncate
  2. Data Manipulation Language(DML)-Insert, Update, Delete
  3. Data Control Language(DCL)-Grant, Revoke
  4. Transaction Control Language(TCL)-Commit, Rollback, Save point
  5. Data Query Language(DQL)-Select

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