Types of DBMS languages
Data Definition Language (DDL)
: Statements are used to define the database structure or schema.
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
Data Manipulation Language (DML)
: Statements are used for managing data within schema objects.
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
Data Control Language (DCL)
GRANT - gives user's access privileges to database
REVOKE - withdraw access privileges given with the GRANT command
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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