DDL is Data Definition Language statements.
Some
examples:-
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CREATE - to create objects in the database
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ALTER - alters the structure of the database
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DROP - delete objects from the database
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TRUNCATE - remove all records from a table
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COMMENT - add comments to the data dictionary
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GRANT - gives user's access privileges to database
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REVOKE - withdraw access privileges given with the
GRANT command
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DML is Data Manipulation Language statements.
Some
examples:-
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SELECT - retrieve data from the a database
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INSERT - insert data into a table
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UPDATE - updates existing data within a table
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DELETE - deletes all records from a table, the space
for the records remain
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CALL - call a PL/SQL or Java subprogram
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EXPLAIN PLAN - explain access path to data
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LOCK TABLE - control concurrency
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DCL is Data Control Language statements.
Some examples:- |
COMMIT - save work done
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SAVEPOINT - identify a point in a transaction to which
you can later roll back
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ROLLBACK - restore database to original since the last
COMMIT
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SET TRANSACTION - Change transaction options like what
rollback segment to use
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