Home » Archive

Articles tagged with: SQL

Magento, Magento 2 »

[29 Aug 2016 | 4 Comments]

This article shows how to write/run/execute custom SQL queries in Magento 2. We need to instantiate class Magento\Framework\App\ResourceConnection for this. You have to inject this resource class in your module’s Block/Model/Controller class constructor. After that, you can use that object to run custom sql queries.
In this example, I will simply be using object manager to instantiate the resource class.

Magento »

[19 Mar 2012 | One Comment]

Here is a quick tip to add OR query and AND query to collection object. I am implementing this on product collection.
Getting product collection

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 foreign key can have a different referenced table.

Magento »

[2 Aug 2010 | 3 Comments]

Scenario:
You have created a custom module.
You have entered certain data in your database.
You need to show the data randomly.
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 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, …

Database, SQL »

[10 Mar 2009 | 2 Comments]

Error description:
Cannot insert the value NULL into column ‘SourceId’, table ‘Advisory.dbo.AdvDocSource’; column does not allow nulls. INSERT fails.
The statement has been terminated. The ‘CompanyAdd’ procedure attempted to return a status of NULL, which is not allowed. A status of 0 will be returned instead.
——————————-

This error occurs because the ‘SourceId’ column in my table is primary key and it is set to not null. i.e. it doesn’t allow null entries. And I have not made it auto increment.