OracleL

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 - delete objects from the database

TRUNCATE -
remove all records from 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 from the a
database

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)

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.

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

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