Char enumerations

karlshea · **Joined:** Thu Oct 16, 2003 3:26 pm **Posts:** 12

I realize that to .net, a char is the same as an int. But for database "readability", we wanted to store the enum's value as a char in the database. But hibernate doesn't save or read the value correctly. When it updates the row, it saves the value as '*' (an invalid value anyway) no matter what it was set as, and then throws an exception ("Input string was not in the correct format") on read because it's trying to convert '*' to an Int32.

Is this just the way it has to be, or is this considered a bug?

KPixel · **Posted:** Wed Aug 24, 2005 9:43 am

KarlShea wrote:

to .net, a char is the same as an int

I don't understand why you are saying that.

Can you post your mapping and the whole exception ?

karlshea · **Joined:** Thu Oct 16, 2003 3:26 pm **Posts:** 12

Well, they're not exactly the same, but you can't have a Char Enum. It's stored as an Int32 behind the scenes.

Code:

public enum GarageType
{
   CodeA = 'A',
   CodeD = 'D',
   Unknown = 'U'
}

is my enum, and if I do

Code:

Enum.GetUnderlyingType(typeof(GarageType))

it returns Int32.

In the mapping file, I have

Code:

<property name="GarageType" type="BuyHomes.Core.Types.GarageType, BuyHomes.Core" />

If the database column is a char(1), '*' gets saved in the column, and when I try to pull it out, an exception is thrown in PersistentEnumType.GetValue, because '*' can't be converted to an Int32, which is what it sees the Enum as.

If the database column is an int, the ASCII value of the character gets stored in the database, and everything works fine.

I was just thinking it would be nice to be able to store the character value in the database instead. If I get some time, I may modify the PersistentEnumType to support this.

KPixel · **Posted:** Thu Aug 25, 2005 7:45 am

Are you sure that it depends of NHibernate ?
It looks like it is a design choice of .NET...

A workaround would be to create an array with all these chars and use the enum to use them:

Code:

char[] GarageType =  new char[] { 'A', 'D', ... }
enum GT
{
   CodeA,
   CodeD,
   Unknown
}

// Usage
Entity.MappedCharProperty = GarageType[GT.CodeD];

karlshea · **Joined:** Thu Oct 16, 2003 3:26 pm **Posts:** 12

Yeah, that would work. When I get some spare time I'm going to try to get it to work in hibernate and submit a patch or something. I was just wondering if there was planned support for storing the characters. Because if I were to do

Code:

GarageType type = (GarageType) 'A'

it would work.

sianabanana · **Joined:** Mon Feb 22, 2010 1:35 pm **Posts:** 3

Did you ever submit that patch?

Gary45 · **Joined:** Tue Oct 19, 2010 9:46 am **Posts:** 1

Hi guys, glad to be a part of your community and hope to enjoy my stay here
__________________
montecristo cigars