Introduction of SQL
SQL (Structure Query Language) was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce in the early 1970s. This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasi-relational database management system.
Features of SQL
- SQL is not a case sensitive language.
- Every commands in SQL should ends with semicolon(;).
- SQL can also called as sequel (SEQUEL).
SQL Sub Language
SQL is mainly divided into four sub language
- Data Definition Language(DDL)
- Data Manipulation Language(DML)
- Transaction Control Language(TCL)
- Data Control Language(DCL)
Only for remember
You can remember all these command like below;
- DDL Commands "dr. cat" d-Drop, r-Rename, c-Create, a-Alter, t-Truncate.
- DML commands "sudi". s-Select, u-Update, d-Delete, i-Insert.