DLL，DML，DCL，TCL in Oracle

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原文链接：http://www.cnblogs.com/alamps/archive/2012/07/29/2614104.html

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#数据库 #java

本文详细介绍了Oracle数据库中使用的四种主要语言：数据定义语言（DDL），用于创建和修改数据库结构；数据操作语言（DML），用于管理和操作数据；数据控制语言（DCL），用于管理权限；事务控制语言（TCL），用于管理DML语句产生的更改。

DLL，DML，DCL，TCL in Oracle

DDL

Data Definition Language （DDL） statements are used to define the database structure or schema. Some examples:

CREATE - to create objects in the database

ALTER - alters the structure of the database

DROP - objects the database

TRUNCATE - remove all records a table， including all spaces allocated for the records are removed

COMMENT - add comments to the data dictionary

RENAME - rename an object

DML

Data Manipulation Language （DML） statements are used for managing data within schema objects. Some examples:

SELECT - retrieve data the a database

INSERT - data into a table

UPDATE - s existing data within a table

DELETE - s all records a table， the space for the records remain

MERGE - UPSERT operation （ or ）

CALL - call a PL/SQL or Java subprogram

EXPLAIN PLAN - explain access path to data

LOCK TABLE - control concurrency

DCL

Data Control Language （DCL） statements.

Some examples:

GRANT - gives user""s access privileges to database

REVOKE - withdraw access privileges given with the GRANT command

TCL

Transaction Control （TCL） statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.

Some examples:

COMMIT - save work done

SAVEPOINT - identify a point in a transaction to which you can later roll back

ROLLBACK - restore database to original since the last COMMIT

SET TRANSACTION - Change transaction options like isolation level and what rollback segment to use

转载于:https://www.cnblogs.com/alamps/archive/2012/07/29/2614104.html