SQL: A Realtional Database Language

 Sql is the query langugae used with relational databases.Sql is not a DBMS itselflkbut ut us a medum of communication with DBMS.SQL is muvh easiet to understand and lwatn as compared to other language.SQL was initially called SEQUEL was later names as SQL during 1970's. Sql is a set based , declarative set based declarative query language and not imperative language such as c or BASIC. Declarative means that user only need to state" what " needs to be done and not how to be done.DBMS determines tand performs internally the steps needed to accomplis the job. It is also known to be non-procedural language

Features of Sql

  sql statements are not case senstive(but data is case sensitive) 

⦁ sql can be written one or more lines

 ⦁ clauses are usually placed on separate lines

 ⦁ Keywords cannot be split across lines

 ⦁ Tabs and spaces are allowed to enhance readability

 ⦁ Each SQL statement (not line) wnds with a semicolon(;)

 ⦁ sql is declarative and non-procedural language.

 ⦁ Sql statement start with verbs(actions) .Example create command.

 ⦁ Identifier always start with alphabet ⦁ single line comment are prefixed by - symbol and multiline comments are enclosed between /* and */

No comments:

Post a Comment