An in-depth overview of INSERT, SELECT, UPDATE, and DELETE statements,
ORDER BY, INNER JOIN, LEFT OUTER JOIN, WHERE, GROUP BY, and HAVING clauses,
and topics such as join tables and sub-queries.
Calculations across objects are ripe for using a map and an inject but frequently, with ActiveRecord, the solution is more elegant and faster if we can have SQL do the work instead.
How moving some data out of the database and into your codebase
as well-named constants can decouple your code and improve performance.
Thoughts on safe indexes to add to Rails app databases.
Sometimes in an app you need to do something in SQL and not in your app’s...
Database normalization, the database world’s equivalent of DRY, can lead you...