Ch. 3: An Introduction to SQL

UPDATE

The command changes a value in a table.

VALUES

The command that is used to include the specific values entered into the table.

USE

The command used to activate the default database.

DROP TABLE

The command used to delete an entire table. Enter the command, followed by the name of the table and a semicolon.

CREATE TABLE

The command used to describe the layout of a table. The command is followed by the name of the table to be created and then by the names and data types of the columns that the table contains.

SELECT

The command used to view the data in a table.

default database

The database to which all subsequent commands pertain. To activate it , execute the USE command followed by the name of the database.

statement history

A special area of memory where the most recent command you entered is stored.

CREATE DATABASE

Command used to create a database followed by the name of the database.

Structured Query Language (SQL)

One of the most popular and widely used languages for retrieving and manipulating database data.

data type

The type of data that an individual column stores.

INSERT

This command adds rows to a table.

DELETE

This command is used to remove a row from a table.

SHOW COLUMNS

This command lists all the columns in a table.

null data value (null)

This data type is used when an actual value is unknown, unavailable, or not applicable.

NOT NULL

This is a clause in a CREATE TABLE command that indicates when a column cannot contain null values.

script file

This is used to executed SQL commands without retyping them, by putting them into a .txt file and entering them as SOURCE.