What are the difference between DDL, DML and DCL commands?

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DDL

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

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CREATE - to create objects in the databaseALTER - alters the structure of the databaseDROP - delete objects from the databaseTRUNCATE - remove all records from a table, including all spaces allocated for the records are removedCOMMENT - add comments to the data dictionaryRENAME - rename an object

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DML


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

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SELECT - retrieve data from the a databaseINSERT - insert data into a tableUPDATE - updates existing data within a tableDELETE - deletes all records from a table, the space for the records remainMERGE - UPSERT operation (insert or update)CALL - call a PL/SQL or Java subprogramEXPLAIN PLAN - explain access path to dataLOCK TABLE - control concurrency

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DCL


Data Control Language?(DCL) statements. Some examples:

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GRANT - gives user's access privileges to databaseREVOKE - withdraw access privileges given with the GRANT command

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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.

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COMMIT - save work doneSAVEPOINT - identify a point in a transaction to which you can later roll backROLLBACK - restore database to original since the last COMMITSET TRANSACTION - Change transaction options like isolation level and what rollback segment to usesee :?http://www.orafaq.com/faq/what_are_the_difference_between_ddl_dml_and_dcl_commands