This article provides the solution to the following MySQL error: The server quit without updating PID file Open terminal Kill the MySQL process There are different ways to kill the MySQL process. You can try any one of them. Below are some of the ways listed: WAY 1 Run the following command to find the … Read more
This article shows how you can create a new database table and install data into the table while installing a custom module or upgrading the module in Magento 2. The install and upgrade setup script file should be inside the Setup folder of your module. The install script should be named InstallSchema.php & InstallData.php and … Read more
MongoDB is an open-source document database. Document in MongoDB means a row or record in the database. A document contains data in key-value pairs. MongoDB is popular for it’s high performance, scalability and availability. This article shows how to perform simple select, insert, update, delete database operations in MongoDB. That’s also referred as CRUD (Create, … 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
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
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: – Open PhpMyAdmin – Go to your database – Click SQL – Run the following SQL Query: SET FOREIGN_KEY_CHECKS=0; UPDATE `core_store` SET store_id = 0 WHERE code='admin'; UPDATE … 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