Data definition language (DDL) statements define, alter the structure of, and drop schema objects. DDL statements enable you to:

Create, alter, and drop schema objects and other database structures, including the database itself and database users (CREATE, ALTER, DROP)
Change the names of schema objects (RENAME)
Delete all the data in schema objects without removing the objects' structure (TRUNCATE)
Grant and revoke privileges and roles (GRANT, REVOKE)
Turn auditing options on and off (AUDIT, NOAUDIT)
Add a comment to the data dictionary (COMMENT)

DDL statements implicitly commit the preceding and start a new transaction. Some examples of DDL statements are:

CREATE TABLE plants  
    (COMMON_NAME VARCHAR2 (15), LATIN_NAME VARCHAR2 (40));

DROP TABLE plants;

GRANT SELECT ON employees TO scott;

REVOKE DELETE ON employees FROM scott;

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DDL包括那些操作