I have recently started using enums to more efficiently store information in a database. I was wondering if there is some way to use them to store multiple true values. To elaborate, in a enum such as GenderEnum I would store male as 0, female as 1, OtherUnclear as 3 in the database.
public enum GenderEnum : short
{
Male,
Female,
OtherUnclear
}
But what if I wanted to store multiple true values? For race for example somebody could be multiracial. How would I store somebody who was, say, Black and White efficiently in a database?
public enum RaceEnum : short
{
White,
Black,
Hispanic,
Asian,
Native,
Unclear
}
If you want an enumeration type to represent a combination of choices, define enum members for those choices such that an individual choice is a bit field. To indicate that an enumeration type declares bit fields, apply the Flags attribute to it.
Below is a simple example.
[Flags]
public enum Days
{
None = 0b_0000_0000, // 0
Monday = 0b_0000_0001, // 1
Tuesday = 0b_0000_0010, // 2
Wednesday = 0b_0000_0100, // 4
Thursday = 0b_0000_1000, // 8
Friday = 0b_0001_0000, // 16
Saturday = 0b_0010_0000, // 32
Sunday = 0b_0100_0000, // 64
Weekend = Saturday | Sunday
}
public class FlagsEnumExample
{
public static void Main()
{
Days meetingDays = Days.Monday | Days.Wednesday | Days.Friday;
Console.WriteLine(meetingDays);
// Output:
// Monday, Wednesday, Friday
Days workingFromHomeDays = Days.Thursday | Days.Friday;
Console.WriteLine($"Join a meeting by phone on {meetingDays & workingFromHomeDays}");
// Output:
// Join a meeting by phone on Friday
bool isMeetingOnTuesday = (meetingDays & Days.Tuesday) == Days.Tuesday;
Console.WriteLine($"Is there a meeting on Tuesday: {isMeetingOnTuesday}");
// Output:
// Is there a meeting on Tuesday: False
var a = (Days)37;
Console.WriteLine(a);
// Output:
// Monday, Wednesday, Saturday
}
}