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Articles tagged with: Database

Database, MySQL »

[7 Feb 2012 | No Comment]

This article shows:- – How to add column to mysql database table after the table has already been created – How to delete column from mysql database table after the table has already been created

Database, MySQL »

[18 Jul 2011 | 3 Comments]

Some definitions of foreign key:- A FOREIGN KEY in one table points to a PRIMARY KEY in another table. A foreign key is a field in a relational table that matches the primary key of another table. The foreign key can be used to cross-reference tables. A table may have multiple foreign keys, and each [...]

Magento »

[15 Nov 2010 | 11 Comments]

In my previous article (Magento: Very Useful Collection Functions), I had written about database interaction functions present in class Varien_Data_Collection_Db. Here, I am going to explain some database interaction functions present in the class Mage_Eav_Model_Entity_Collection_Abstract. These collection functions are very useful to select data from Magento database. We need them almost all the time for [...]

Magento »

[12 Jul 2010 | 25 Comments]

I got this error message when migrating my Magento files and database from one server to another. Notice: Undefined index: 0 in app/code/core/Mage/Core/Model/Mysql4/Config.php on line 92 Solution:

Database, MySQL, SQL »

[15 May 2010 | 2 Comments]

The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables. [@via w3schools] A SQL JOIN clause combines records from two or more tables in a database. It creates a set that can be saved as a table or [...]

Magento »

[7 Dec 2009 | 6 Comments]

Suppose, you have a module called MyModule. Its version is 0.1.0. Now, you want to do some database changes for the module. You have the mysql setup file (mysql install file) mysql4-install-0.1.0.php in MyModule/sql/mymodule_setup folder of your module. You don’t need to make direct changes to database. You can upgrade your module to make your [...]

Magento »

[27 Nov 2009 | 10 Comments]

Difference between EAV and Flat Catalog In EAV database model, data are stored in different smaller tables rather than storing in a single table. Like, product name is stored in catalog_product_entity_varchar table

PEAR, Smarty »

[18 Jul 2008 | One Comment]

For using database, you need to install a package of PEAR called ‘MDB2’ along with the installation of PEAR and Smarty. MDB2 provides a common API for all support RDBMS.

Database, MySQL »

[10 Oct 2007 | No Comment]

This article shows how to backup and restore single & multiple databases and tables in MySQL. 1) Backup single database mysqldump -h hostname –u username –p password database_name > /path/backup.sql

MySQL »

[6 Sep 2007 | No Comment]

Problem: “Fails to start the service. Please wait 30 seconds to try again.” I faced this problem 2 years back when I was a newbie to MySQL. I was just starting to learn PHP and MySQL at that time.