Performance Of Set-Type Data Types Created Using CLR

In my applications, I often encounter situations where the domain of a type is some set (e.g. Student, Staff etc. for Membership type etc.). A common solution is to assign integral values to each possible value of the set & convert them to corresponding strings programatically when fetching data, or use a Foreign Key into a relation defining each of the unique value.

MySql has a Set Data type. So, this time around, I decided to do the same with Sql Server, and resorted to CLR to create a custom data type, whose domain could only be a collection of predefined strings or other data types.

But, just before deploying the assembly, the performance bug struck me. So, assuming a simple custom data type, like:





Code Snippet

<Serializable()> _
<Microsoft.SqlServer.Server.SqlUserDefinedType(Format.Native)> _
Public Structure MemberType
Implements INullable

Private Const Student As String = "Student"
Private Const Staff As String = "Staff"

Private memType As Int16
Private m_Null As Boolean

Public Overrides Function ToString() As String
If (Me.m_Null) Then
Throw New SqlTypes.SqlNullValueException("Null Reference Exception")
End If

Select Case memType
Case 1
Return Student
Case 2
Return Staff
Case Else
Throw New Exception("Invalid State for MemberType")
End Select
End Function

Public ReadOnly Property IsNull() As Boolean Implements INullable.IsNull
Get
' Put your code here
Return (Me.m_Null)
End Get
End Property

Public Shared ReadOnly Property Null() As MemberType
Get
Dim h As MemberType = New MemberType
h.m_Null = True
Return h
End Get
End Property

Public Shared Function Parse(ByVal s As SqlString) As MemberType
If s.IsNull Then
Return Null

ElseIf (StrComp(s.ToString(), Student, CompareMethod.Text) = 0) _
OrElse StrComp(s.ToString(), "1") = 0 Then
Dim u As New MemberType
u.memType = 1
u.m_Null = False

Return (u)

ElseIf (StrComp(s.ToString(), Staff, CompareMethod.Text) = 0) _
OrElse StrComp(s.ToString(), "2") = 0 Then
Dim u As New MemberType
u.memType = 2
u.m_Null = False

Return (u)

Else
Throw New SqlTypes.SqlTypeException("Invalid Value for MemberType")
End If
End Function
End Structure
Would it be a performance issue, if I use such Data types, whose data is fetched or updated frequently???