Programming PHP

Example 8-2. Database schema (continued)
address varchar(255) NOT NULL,
city varchar(128) NOT NULL,
telephone varchar(64) NOT NULL,
url varchar(255),
PRIMARY KEY (business_id),
UNIQUE business_id (business_id),
KEY business_id_2 (business_id)
);
# --------------------------------------------------------
#
# Table structure for table 'categories'
#
CREATE TABLE categories (
category_id varchar(10) NOT NULL,
title varchar(128) NOT NULL,
description varchar(255) NOT NULL,
PRIMARY KEY (category_id),
UNIQUE category_id (category_id),
KEY category_id_2 (category_id)
);
Database Connection
We’ve designed these pages to work with a MySQL, PostgreSQL, or Oracle 8i backend.
The only visible sign of this in the PHP code is that we use commit( ) after every
update. We’ve abstracted the database-specific stuff to a db_login.php library, shown
in Example 8-3, which selects an appropriate DSN for MySQL, PostgreSQL, or Oracle.
Example 8-3. Database connection abstraction script (db_login.php)