What is the point (if any) in having a table in a database with only one row?
Note: I'm not talking about the possibility of having only one row in a table, but when a developer deliberately makes a table that is intended to always have exactly one row.
Edit:
The sales tax example is a good one.
I've just observed in some code I'm reviewing three different tables that contain three different kinds of certificates (a la SSL), each having exactly one row. I don't understand why this isn't made into one large table; I assume I'm missing something.
I've seen something like this when a developer was asked to create a configuration table to store name-value pairs of data that needs to persist without being changed often. He ended up creating a one-row table with a column for each configuration variable. I wouldn't say it's a good idea, but I can certainly see why the developer did it given his instructions. Needless to say it didn't pass review.
I've just observed in some code I'm reviewing three different tables that contain three different kinds of certificates (a la SSL), each having exactly one row. I don't understand why this isn't made into one row; I assume I'm missing something.
This doesn't sound like good design, unless there are some important details you don't know about. If there are three pieces of information that have the same constraints, the same use and the same structure, they should be stored in the same table, 99% of the time. That's a big part of what tables are for fundamentally.