This article shows how to create a CRUD (Create, Read, Update, Delete) application system with PHP & MySQL using Object Oriented Programming (OOP) technique. I had written an article before about creating Simple CRUD application with PHP & MySQL but that has been programmed with procedural way. In this article, we create the same kind … Read more
This article shows SQL query to get size (in MB) of all MySQL databases. It also shows the query to get the size (in MB) of all the tables present in any particular database. Get size (in MB) of all MySQL databases SELECT table_schema "Database Name", sum( data_length + index_length ) / 1024 / 1024 … Read more
Function addExpressionAttributeToSelect as defined in Mage_Eav_Model_Entity_Collection_Abstract (/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php) allows us to use MySQL functions in Magento collection. Here is an example of using MySQL function CONCAT in Magento customer collection to concat customer’s firstname and lastname: $collection = Mage::getResourceModel('customer/customer_collection') ->addExpressionAttributeToSelect('fullname', 'CONCAT({{firstname}}, " ", {{lastname}})', array('firstname','lastname')); Here is another example which uses MySQL function MONTH which fetches … Read more
Here are step-by-step commands about installing apache, php, mysql, and phpmyadmin on ubuntu. 1) Open Terminal – Press: CTRL + ALT + T 2) Install Apache – In terminal, type: sudo apt-get install apache2 – To test if Apache installation, Open browser and type: http://localhost – It should show text: It Works! 3) Install PHP … Read more
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 – How to add foreign key to table column after the table has already been created Basically, all this can … Read more
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 … Read more
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 … Read more
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 … Read more
Suppose, you have a product collection and you want to filter it by category. Suppose, you want to filter it by more than one category. You can use addCategoryFilter if you have only one category. But, what if you want to filter by more than one category? Category ids are stored for product in a … Read more