Last week I posted how to configure and test Ruby and MySQL. Somebody asked me how to handle a dynamic list of columns. So, here’s a quick little program to show you how to read the dynamic list of column:

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require 'rubygems'
require 'mysql'
 
# Begin block.
begin
  # Create a new connection resource.
  db = Mysql.new('localhost','student','student','studentdb')
 
  # Create a result set.
  rs = db.query('SELECT item_title, item_rating FROM item')
  # Read through the result set hash.
  rs.each do | row |
    out = ""
    i = 0
    while i < db.field_count
      # Check if not last column.
      if i < db.field_count - 1
        out += "#{row[i]}, "
      else
        out += "#{row[i]}" …

Sometimes trying to keep a post short and to the point raises other questions. Clearly, my Python-MySQL Program post over the weekend did raise a question. They were extending the query example and encountered this error:

      TypeError: range() integer end argument expected, got tuple.

That should be a straight forward error message because of two things. First, the Python built-in range() function manages a range of numbers. Second, the row returned from a cursor is actually a tuple (from relational algebra), and it may contain non-numeric data like strings and dates.

The reader was trying to dynamically navigate the number of columns in a row by using the …

Configuring Perl to work with MySQL is the last part creating a complete Fedora Linux LAMP stack for my students. Perl is already installed on Fedora Linux.

I’ve also shown how to use PHP, Python, and Ruby languages to query a MySQL database on Linux. After installing this additional Perl DBI library, my students will have the opportunity to choose how they implement their LAMP solution.

You can find the Perl version with the following version.pl program:

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#!/usr/bin/perl -w
 
# Print the version.
print "Perl ".$]."\n";

This post works through the Python configuration of Fedora instance, and continues the configuration of my LAMP VMware instance. It covers how you add the MySQL-python libraries to the Fedora instance, and provides the students with one more language opportunity for their capstone lab in the database class.

A standard Fedora Linux distribution installs Python 2.7 by default. Unfortunately, the MySQL-python library isn’t installed by default. You can verify the Python version by writing and running the following version.py program before installing the MySQL-python library:

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# Import sys library.
import sys
 
# Print the Python version.
print sys.version

You can run the version.py program dynamically like this from the current working directory:

After you install Ruby and build the Rails framework, you need to create the mysql gem. This blog post shows you how to create the mysql gem and how to write a simple Ruby program that queries the MySQL database.

The first step creates the mysql gem for Ruby programming:

yum install mysql

It should show you the following:

Fetching: mysql-2.9.1.gem (100%)
Building native extensions.  This could take a while...
Successfully installed mysql-2.9.1
Parsing documentation for mysql-2.9.1
Installing ri documentation for mysql-2.9.1
Done installing documentation for mysql after 0 seconds
1 gem installed

After you install the mysql Ruby Gem, you can write and …

I use a Fedora 20 VM image to teach Oracle and MySQL technology. Last week, I expanded the Fedora VM image to support a full LAMP stack. This blog shows you how to install Ruby on Fedora and successfully generate the Rails gems.

Connect as the root user and use yum to install the libraries. My approach is by library or small groups. Naturally, you start with the ruby library.

yum install ruby

You will see the following:

Loaded plugins: langpacks, refresh-packagekit
mysql-connectors-community                                  | 2.5 kB  00:00     
mysql-tools-community                                       | 2.5 kB  00:00     
mysql56-community                                           | 2.5 kB  00:00     
pgdg93                                                      | 3.6 kB  00:00     
updates/20/x86_64/metalink …

Everything seemed complete after configuring my standalone MySQL instance to a LAMP installation, but last night I started playing with the image files. It turns out that I failed to install the php-gd library.

There’s very little feedback when you try to troubleshoot why you can’t read an image. In fact, the error message for reading the BLOB from MySQL was only available on the local Firefox browser:

      The image "http://localhost/ConvertMySQLBlobToImage.php" cannot be displayed because it contains errors.

The fix requires root to install the php-gd library with the yum utility:

yum install php-gd

You’ll need to answer …

While I try to keep things simple, sometimes eliminating options and explanations comes back to haunt me. After posting how to open a Fedora firewall port for a LAMP stack, somebody got trapped by my instructions for installing MySQL on Fedora. They got stuck because they had the following setting in their /etc/my.cnf file:

bind-address=localhost.localdomain

I’d suggested using that bind-address value for a DHCP VMware Fedora installation in Step #7. I was trying to create an example for an isolated testing instance, which is why I set the bind-address to a localhost.localdomain value. They raised the following error when they …

My students wanted an extra credit assignment, so I thought a LAMP configuration and test would be appropriate. The only problem was I hadn’t added it to their course VMware instance. So, here are the instructions to install Apache2, PHP, and MySQLi for a complete LAMP stack when MySQL is already installed.

The post builds on my Fedora Install of MySQL and MySQL Workbench on Fedora posts from last year. It also presumes that you’ve installed a studentdb database but you need to know how to do that let me know (but it hasn’t changed much from the example at the bottom of this old MySQL 5.1 blog post).

You …

Installing Apache2 With PHP5 And MySQL Support On Fedora 21 (LAMP)

LAMP is short for Linux, Apache, MySQL, PHP. This tutorial shows how you can install an Apache2 webserver on a Fedora 21 server with PHP5 support (mod_php) and MySQL support.