Sams Teach Yourself SQL

Appendix A. Common SQL Commands

The following appendix details some of the most common SQL commands that you will use. As we have stated throughtout the book, check your database documentation, as some of the statements will vary depending upon your implementation.

SQL Statements

ALTER TABLE

ALTER TABLE TABLE_NAME
[MODIFY | ADD | DROP]
  [COLUMN COLUMN_NAME][DATATYPE|NULL NOT NULL] [RESTRICT|CASCADE]
[ADD | DROP]  CONSTRAINT CONSTRAINT_NAME]

Description: Alters a table’s columns.

COMMIT

COMMIT [ TRANSACTION ]

Description: Saves a transaction to the database.

CREATE DOMAIN

CREATE DOMAIN DOMAIN_NAME AS DATA_TYPE [ NULL | NOT NULL]

Description: Creates a domain—an object that is associated with a data type and constraints.

CREATE INDEX

CREATE INDEX INDEX_NAME