organization of crud for postgrsql

I am using an AWS managed version of Postgrsql. I have also found a document called "Postgrsql CRUD operations in PHP" https://www.idiotinside.com/2015/07/25/p...ns-in-php/. The reason for using Postgrsql is that it can handle a blob larger than 1M. The reason for using the AWS RDS rather than postgres in a container to keep the size down. I have a bunch of files to store in it such as .xls, .pdf, .ppt. My question is regarding the organization of Codeigniter files in the project. I of course have a controller that runs the UI. I'd like to be able to call the  CRUD functions and I'd like to keep them in a separate module from the controller. Where should I put them so that I can call the functions directly from the controller?

proof that an old dog can learn new tricks