PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

234 Chapter 9 Creating Your Web Database
MySQL then displays a list of all the tables in the database:
+-----------------+
| Tables in books |
+-----------------+
| book_reviews |
| books |
| customers |
| order_items |
| orders |
+-----------------+
5 rows in set (0.06 sec)
You can also use show to see a list of databases by typing
mysql> show databases;
If you do not have the SHOW DATABASES privilege, you will see listed only the databases
on which you have privileges.
You can see more information about a particular table, for example, books, using
DESCRIBE:
mysql> describe books;
MySQL then displays the information you supplied when creating the database:
+--------+------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+------------+------+-----+---------+-------+
| isbn | char(13) | NO | PRI | NULL | |
| author | char(50) | YES | | NULL | |
| title | char(100) | YES | | NULL | |
| price | float(4,2) | YES | | NULL | |
+--------+------------+------+-----+---------+-------+
4 rows in set (0.00 sec)
These commands are useful to remind yourself of a column type or to navigate a database
that you didn’t create.
Creating Indexes
We briefly mentioned indexes already, because designating primary keys creates indexes
on those columns.
One common problem faced by new MySQL users is that they complain about
poor performance from this database they have heard is lightning fast.This performance