I am currently refactoring a project where so far a lot of data was kept as constants and arrays in the code. Also there are a lot of redundancies. Now I want to move all that data into the db, but I am not sure how I would do the mapping. The data is rarely dynamically selected based on user input but rather specifically selected in the code. It is used at a very core level of the application, but it is actually not THE core. Also a database is already being used, so there would be no real extra effort.
My idea would be to use a Mapping class in which I have constants pointing to the IDs of the respective rows. Is that a good idea?
Another idea would be to index the name row and just directly query for the names.
The database would probably have the following columns: id, name, polynom and params.
So, basically we are talking math data. For example: 1, “Price approximation”, 20x^3 – 5x^2 + 11x”, “non-cumulated”.
I think this question is language-agnostic but since there might be a language-specific (or even framework-specific) best practice, here is what I use: PHP5 with the Yii Framework.
I don’t have much experience with PHP nor Yii, but here is my 2 cents…
If these are constants and collections of constants that technically define your application (application architecture constants), but the end-user shouldn’t have control over, I would put them in a configuration file instead of your database, unless you’ve built a module to easily access and modify them. Whether you implement a mapping class (or a configuration class) to retrieve them is not important, but be consistent in how you retrieve them. If you have too many to manage in a configuration file, then storing them in the database would be appropriate, but make sure you provide an easy way to modify them. To make your source code readable, I’d use descriptors that a human can understand and map those descriptors to the respective row like you mentioned.
If these are user defined constants, then you should definitely provide an interface. But keep the same architecture as the application architecture constants.
In a perfect program/application (or even better–an application framework), nothing is hard coded, and everything is controlled by constants (switches). If you’re able to achieve this successfully without the need to maintain your source code, you will win the Nobel Peace Prize.