Statements in Oracle

Data Definition Language (DDL) 

               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
        ADD
        RENAME
        MODIFY
        DROP
    DROP - delete objects from the database
    TRUNCATE - remove all records from a table,       
               including all spaces allocated for the records are removed
    RENAME - rename an object
   
   
Data Manipulation Language (DML) 

            DML statements are used for managing data within schema objects. Some examples:

    INSERT - insert data into a table
    UPDATE - updates existing data within a table
    DELETE - deletes all records from a table, the space for the records remain
    MERGE  - UPSERT operation (insert or update)
  
   
Data Control Language (DCL) 

            DCL statements. Some examples:

    GRANT  - gives users access privileges to database
    REVOKE - withdraw access privileges given with the GRANT command
   
   
Transaction Control (TCL) 

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

    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