The forgotten PHP logical operator
Posted in: php | November 4, 2011 | ( 4 ) Comments
It is very rare that I have seen some code that employs the PHP XOR logical operator. It is not the case that it is not required or programmers are unfamiliar with it; it probably seems that most programmers have become comfortable with using the more common ‘&&’ and ‘||’ operators to construct all logical comparisons; the XOR operator relegated to the subconscious black hole.
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Grabbing the referrer search engine keywords for a site
Posted in: php | October 17, 2011 | ( 11 ) Comments
A couple of weeks back I had to write a solution for a client to track the referrer search engine from where the user came to his sites contact page, without using Google Analytics. If a user was to fill the contact form on the website, the referring search engine name and the keyword for which it was refereed was to be emailed along with the contact information. The following is a solution for the same.
To get the referrer information we need to use the $_SERVER['HTTP_REFERER'] variable and store it in a session so that it is not overwritten as the user browses the site before he submits the contact information. If the users comes to the website from a search engine he could land on any page, so we need to add some code to capture the referrer url on each page of the site. We only need to save the referrer if the referrer is from outside the current domain.
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Building Reactive web content
Posted in: interface,javascript | October 12, 2011 | ( 1 ) Comment
Reading is an active process. Weather you are reading a web page, a book or any other media, the information tends to generate ideas in the mind of the reader. An active reader asks questions, considers alternatives, questions assumptions and analyses the argument of the author. An active reader doesn’t passively store up information, but uses the author’s arguments to create a framework to further up his ideas and understanding.
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How to check when a MySQL table was last updated
Posted in: mysql | October 4, 2011 | ( 3 ) Comments
I recently had to update a MySQL schema and import new data into the table. But before I could do that I needed to check that no one had updated the table during the last 7 days and no new data had been stored. As the table itself did not have any update field of itself the only other option was to look into the MySQL ‘information_schema’ database.
The ‘information_schema’ database contains a ‘tables’ table which contain the update information for each database and its tables. So all you have to do is grab that information.
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Splitting large MySQL dump files
Posted in: mysql,php | October 2, 2011 | ( 5 ) Comments
One of the frustrating things with working with MySQL is of importing large sql dump files. Either you get a ‘max execution time exceeded’ error from PHP or a ‘Max_allowed_packet_size’ from MySQL. In a recent task I needed to import a table of around a million records on a remote host, which quickly became an exercise in frustration due to various limitations on the server. SSH was of no help as changing the configuration files was restricted to the root user.
My last resort was to split the huge ‘INSERT’ statements into smaller size files. Manually doing the same is obviously time consuming and error prone; the only other solution is to write a small script to split the insert statements. This was to be a quick hack so the parsing code was to be of minimum complexity. Splitting a sql dump containing extended insert statements is somewhat complex so you need to have the dump file in a simple format – each insert statement should be on its own line as shown below.
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Migrating Access MDB to MySQL
Posted in: data,mysql | September 26, 2011 | ( 2 ) Comments
A recent task needed me to import a large amount of data from a Access MDB database to MySQL. My first choice for the job was the mdb-tools set of utilities. mdb-tools provides a set of tools and applications to export MDB data and schema to other databases such as MySQL, Oracle, Sybase, PostgreSQL, and others.
mdb-tools is available for Linux systems, and as I use Ubuntu, installation was a breeze using the package manager. To install is from the shell use the following.
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