Oracle SQL Statements

• Query statements Allow you to retrieve rows stored in database tables. You write a query using the SQL SELECT statement.

• Data Manipulation Language (DML) statements Allow you to modify the contents of tables. There are three DML statements:

  • INSERT Allows you to add rows to a table.

  • UPDATE Allows you to change a row.

  • DELETE Allows you to remove rows.

• Data Definition Language (DDL) statements Allow you to define the data structures, such as tables, that make up a database. There are five basic types of DDL statements:

  • CREATE Allows you to create a database structure. For example, CREATE TABLE is used to create a table; another example is CREATE USER, which is used to create a database user.

  • ALTER Allows you to modify a database structure. For example, ALTER TABLE is used to modify a table.

  • DROP Allows you to remove a database structure. For example, DROP TABLE is used to remove a table.

  • RENAME Allows you to change the name of a table.

  • TRUNCATE Allows you to delete the entire contents of a table.

• Transaction Control (TC) statements Allow you to permanently record the changes made to the rows stored in a table or undo those changes. There are three TC statements:

  • COMMIT Allows you to permanently record changes made to rows.

  • ROLLBACK Allows you to undo changes made to rows.

  • SAVEPOINT Allows you to set a “savepoint” to which you can roll back changes made to rows.

• Data Control Language (DCL) statements Allow you to change the permissions on database structures. There are two DCL statements:

  • GRANT Allows you to give another user access to your database structures, such as tables.

  • REVOKE Allows you to prevent another user from accessing to your database structures, such as tables.