Data manipulation language (DML) statements query or manipulate data in existing schema objects. They enable you to:

Retrieve data from one or more tables or views (SELECT); fetches can be scrollable (see "Scrollable Cursors")
Add new rows of data into a table or view (INSERT)
Change column values in existing rows of a table or view (UPDATE)
Update or insert rows conditionally into a table or view (MERGE)
Remove rows from tables or views (DELETE)
See the execution plan for a SQL statement (EXPLAIN PLAN)
Lock a table or view, temporarily limiting other users' access (LOCK TABLE)

DML statements are the most frequently used SQL statements. Some examples of DML statements are:

SELECT last_name, manager_id, commission_pct + salary FROM employees;

INSERT INTO employees VALUES 
    (1234, 'DAVIS', 'SALESMAN', 7698, '14-FEB-1988', 1600, 500, 30);

DELETE FROM employees WHERE last_name IN ('WARD','JONES');

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DML包括那些操作