sql commands
The purpose of this entry is not to teach sql commands, not writing about how to learn sql commands or learn basic sql statements. This is to classify the categories of diferent sql commands and try to solve a mystory category. I thought about it while working on database management application, how to describe the fifth subset of sql commands inside sql language.
SQL commands can be divided into three main categories. The Data Definition Language (DDL) section contains the commands used to create, alter and destroy databases and database objects. After the database structure is defined using DDL statements, DBA and Developers or any other users can utilize the Data Manipulation Language (DML) to insert, delete, retrieve and modify the data contained in database objects. To perform DDL or DML statements there is another set of sql commands / sub language which is used to grant access to database and database objects called Data Control Language (DCL) which is used to maintain security of database and objects within the database. The fourth one is Transaction Control Language (TCL) used to control multiple DML commands in single transaction. Now this fifth one which i tried to search online and offline with out any luck could be Server Control Language (SCL) to control the database server behaviour using sql commands, since it is not part of acctual sql standards you dont hear about it. As the database systems are growing and war of database vendors are based on features then standards, there is a new set of language is neccessary to control the database servers which i will call it SCL or server control language, it can be server configuration language or system control language. I also strong feel it should be called DAL (database administration language).
Here is the quick break down.
Data Definition Language - DDL
The commands which are used to define database and objects comes under DDL. Some examples of DDL commands
USE
CREATE
ALTER
DROP
Data Manipulation Language - DML
SQL commands used to manipulate data inside database objects are part of DML language. These can vary by each vendor, here are some example commands which should be present in all database systems.
SELECT
UPDATE
DELETE
INSERT
Data Control Language - DCL
Control language is for data security purpose to give authorization to users or group of users to perform certian actions in database.
GRANT
REVOKE
Transaction Control Language - TCL
Each command is a transaction for database, some times a set of commands are called transactions, specially when you are runnings more than one command to complete the work. Example could be delete some records and update the rest of the records, now you want to make sure that if delete operation is successful then run the update other wise roll back. In situation like these database systems have commands to run all commands as single transaction.
START TRANSACTION
ROLL BACK
COMMIT
Server Control Language / Database Administration Language - DAL - SCL
This is the Database Administrator Language. These commands vary by each vendor depending on each database vendor they have introduced new commands and ways of writing the SQL commands. These commands are used to alter database server settings, in the background these settings configuration might be saved inside a database table but for DBA they are like same like SELECT statement.
If other DBA developers have better term then i would like to know. What do they call DAL SCL.