Introduction to SQL

 WHAT IS SQL?

    SQL stands for Structured Query Language. SQL is used to communicate with a database. It is the standard language for relational database management systems. SQL statements are used to perform tasks such as updati
ng data on a database or retrieving data from a database. Some common relational database management systems that use SQL are Oracle, Sybase, Microsoft SQL Server, Access, Ingres, etc.

    Although most database systems use SQL, most of them also have their own additional proprietary extensions that are usually only used on their system. However, the standard SQL commands such as “Select”, “Insert”, “Update”, “Delete”, “Create”, and “Drop” can be used to accomplish almost everything that one needs to do with a database.

WHAT SQL CAN DO?

1. SQL can execute queries against a database
   
2. SQL can retrieve data from a database  
   
3. SQL can insert records into a database  
4. SQL can update records in a database 
5. SQL can delete records from a database 
6. SQL can create new databases 
7. SQL can create new tables in a database 
8. SQL can create stored procedures in a database 
9.  SQL can create views in a database 
10. SQL can set permissions on tables, procedures, and views

SQL COMMANDS

• SELECT - extracts data from a database 
  
•  UPDATE - updates data in a database 
•  DELETE - deletes data from a database 
•  INSERT INTO - inserts new data into a database 
•  CREATE DATABASE - creates a new database 
•  ALTER DATABASE - modifies a database 
•  CREATE TABLE - creates a new table 
•  ALTER TABLE - modifies a table 
•  DROP TABLE - deletes a table 
•  CREATE INDEX - creates an index (search key) 
•  DROP INDEX - deletes an index