Question

I have a MySQL database which currently uses a tinyint field to store the type of record. It uses an odd numbering, and we are in the process to change this. So currently, it reads:

record type
1      60
2      62
3      60
4      61
5      63

The numbers represent the type, with:

60 = car
61 = bike
62 = motorcycle

We need to transform this into an enum field, using the values car, bike, motorcycle. However, the table in question in being used from a very large number of pages, where SELECTs and INSERTs are being made using the original numbers. That will change gradually. So I was wondering: is there a way to change the indexes of the enum field, so that I could change the field to enum and still save a new record with type = 60, and this becomes ‘car’? I know there is a way to set it to 0 and it will become car, but clearly that requires us to change all of the pages and there is no time for this…

Answer 1

Unfortunately this is not possible. The manual itself leaves no room for hope:

Each enumeration value has an index:

• Values from the list of permissible elements in the column
specification are numbered beginning with 1.

Seeing as there’s nothing you can do about that, I have to ask: why do you need to make this an enum? I have yet to come across a situation where an enum provided any benefit apart convenience to programmers who look at query results by eye. What is the benefit you are looking to gain? I am no guru, but IMHO no matter what you want to achieve there is another (better) way than using an enum.