Interfacing Relational Databases to the Web
Why would one want to link a database to the web? A better question might be, “Why wouldn't one want to link a database to the web?” Static HTML pages are good for many things: documentation, hypertext books, personal pages and other unchanging information. However, static pages present a few problems:
Static pages can be a hassle to maintain. If one is managing a large site with thousands of pages, changing just the “look and feel” of the site will involve either an inordinate amount of work or a long evening with CGI and Perl. This gets even nastier when the content of the site changes.
Static pages don't allow for user input, feedback or collaboration. Suppose you want to add a message board to your static web site. You can set up a form that mails user comments to the webmaster, who manually puts them on a page—you can even set up a script to do this. However, this presents a few problems, as we shall discuss later.
Static pages don't allow you to operate a web service. One can operate a web site with static HTML, but some of the most useful web sites today, such as Slashdot (http://slashdot.org/), CNN (http://www.cnn.com/) and Amazon.com (http://www.amazon.com/), are services offering dynamic database-backed content.
I hope this quick rundown is enough to convince you that you really want to use a database for your dynamic web site. In this article, I will present instructions for installing PHP3 (http://www.php.net/) and PostgreSQL (http://www.postgresql.org/), a little bit of theory, some instructions for using SQL and PHP3, and an example application.
This description assumes you are running Red Hat, but most of these instructions will be applicable to other distributions; these tools are fairly painless to install from source, anyway.
Here's a list of what you'll need to run the example application and develop your own applications:
Apache 1.3 or greater. You will need at least version 1.3, because 1.2 does not support modules, and PHP is faster and more secure as a module. On a Red Hat system, you'll need both the apache and apache-devel packages. (Make sure you have the file apxs installed, because we're going to recompile the PHP3 Apache module.)
The source RPM for PHP3, version 3.0 or greater.
PostgreSQL 6.4 or greater; the example code will not run on version 6.3 without a little editing, because 6.4 has an SQL parser.
To rebuild PHP3 for PostgreSQL support, take the following steps:
Use su to become root.
Install the source RPM for PHP3 (rpm -ihv mod_php3-3.0.5-2.src.rpm on Red Hat 6.0). This will place a “spec file” in the directory /usr/src/redhat/SPECS and a tar file of the source in /usr/src/redhat/SOURCES. Since the PHP module that comes with Red Hat doesn't have database support enabled by default, we'll have to recompile it. RPM makes this fairly painless.
Because the PHP3 installation process assumes a default PostgreSQL installation, not the Red Hat one, we'll need to make some symlinks. Create a directory /usr/local/pgsql and make symbolic links from /usr/include/pgsql to /usr/local/pgsql/include and from /usr/lib/ to /usr/local/pgsql/lib.
Invoke your favorite editor on the spec file (mod_php3.spec) and search for ./configure; then add the configure option --with-pgsql.
Now build a binary package with rpm: /rpm -bb mod_php3.spec/
If all goes well, you'll have a binary package in /usr/src/redhat/RPMS/arch, where /arch is your architecture. Install it, and you're ready to move on.
Fast/Flexible Linux OS Recovery
On Demand Now
In this live one-hour webinar, learn how to enhance your existing backup strategies for complete disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible full-system recovery solution for UNIX and Linux systems.
Join Linux Journal's Shawn Powers and David Huffman, President/CEO, Storix, Inc.
Free to Linux Journal readers.Register Now!
- Devuan Beta Release
- May 2016 Issue of Linux Journal
- EnterpriseDB's EDB Postgres Advanced Server and EDB Postgres Enterprise Manager
- The US Government and Open-Source Software
- Tech Tip: Really Simple HTTP Server with Python
- The Humble Hacker?
- BitTorrent Inc.'s Sync
- The Death of RoboVM
- Open-Source Project Secretly Funded by CIA
- New Container Image Standard Promises More Portable Apps
In modern computer systems, privacy and security are mandatory. However, connections from the outside over public networks automatically imply risks. One easily available solution to avoid eavesdroppers’ attempts is SSH. But, its wide adoption during the past 21 years has made it a target for attackers, so hardening your system properly is a must.
Additionally, in highly regulated markets, you must comply with specific operational requirements, proving that you conform to standards and even that you have included new mandatory authentication methods, such as two-factor authentication. In this ebook, I discuss SSH and how to configure and manage it to guarantee that your network is safe, your data is secure and that you comply with relevant regulations.Get the Guide