Articles tagged with: Database
Magento »
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 »
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 used as is. A JOIN is a means for combining fields from two tables by using values common to each. ANSI standard SQL specifies four types of JOINs: INNER, OUTER, LEFT, and RIGHT. In special cases, …
Magento »
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 necessary database changes. To do so,
Magento »
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
product id is stored in catalog_product_entity_int table
product price is stored in catalog_product_entity_decimal table
PEAR, Smarty »
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.
MySQL »
1) To make a backup of a single MySQL database
You have to make backup before you enter inside your MySQL system i.e. by typing mysql –u username –p password . (Here, username and password indicates your MySQL server username and password.)
MySQL »
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.

