In programming, you may hear someone describe a program as a “CRUD application”.
CRUD is an acronym that stands for: Create, Read, Update, and Delete
A CRUD application is one that doesn’t do much processing (calculations). It’s basically written to store and retrieve data in a database.
For example, think of a recipe program.
The program would let you CREATE recipes and save them to the database. It would let you READ recipes from the database. If you want to change the recipe, the program would let you UPDATE the recipe and save the changes to the database. And, if you don’t want to use the recipe any longer, you could DELETE the recipe from the database.
The program may do some calculations. It might let you change the number of servings and it would change the quantities of the ingredients. But that’s about all the “processing” the program would do.
Another CRUD app might be a “to do” app. You create, read, update, and delete tasks. It might also give you a report of percent of tasks completed.
Non-CRUD apps are things like a tax calculating program. That program would have CRUD features, so you could enter your final transactions, but it would also include a lot of calculations. These calculations will need more complex, thorough testing. The reason a programmer would call something a “CRUD app” is to identify the scope of work it would take to complete. A CRUD program usually has simple requirements: identifying the data it will store, the validation rules for the data, and the entry/editing/reporting screen formats.