Database Formalities

Most application development can essentially be described as formalizing a business process. You take an informal process, remove the ambiguity that’s invariably present, adapt it to computer interfaces, and restate that process in a formal language. This has many benefits, among them:

  • Automation – This is the most obvious benefit of using a programming language to formalize a process. The computer can now understand the process, and can execute the process without unnecessary human intervention.
  • Unambiguous – Ambiguity can be removed without actually creating an application, but you can’t create an application without removing the ambiguity. Some of it is removed through discussions with others involved in the project, but most is resolved through the intuition of the application developer.
  • The ability to handle complexity – Simple processes can be handled correctly by humans using intuition, rules of thumb, and following patterns. But complex processes are much easier to solve with a formal process that has independently verifiable parts.

Terminology Confusion

I recently read the following article, another opinion in the long-standing surrogate key vs. natural key “debate”:

I put “debate” in quotes because it’s filled with so much confusion, I don’t think most people understand what they’re arguing over. People use different definitions for surrogate keys, often in the same discussion, so for the purposes of this article I’ll define surrogate key to mean: “A system generated key that is not derived from the business rules, hidden from the business, but visible to the application”. The surrogate key is used to take the place of a natural key, which is derived from the business rules. In other words, a surrogate key is a pointer.

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On ORMs and "Impedence Mismatch"

The solution ORMs provide is to “map” an object class, which is a type (or domain), onto a table, which is a relation variable (a.k.a. relvar). This supposedly abstracts away an “impedance mismatch” between the two. ORMs are already off to a bad start, mapping a type to a variable, but I’ll continue.

The real impedance mismatch is a set of very fundamental differences between application data and data in a well-designed relational database.

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