DataRelation Problem

[Tengkorak]

i try to create DataRelation and get error

here my code:

Public Class Form1
    Dim ds As DataSet
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ds = New DataSet
 
        Dim dt As New DataTable("dtCustomer")
 
        Dim fid As New DataColumn("id", System.Type.GetType("System.Int32"))
        Dim fkd As New DataColumn("kode", System.Type.GetType("System.String"))
        Dim fnm As New DataColumn("Name", System.Type.GetType("System.String"))
        Dim fkel As New DataColumn("idkel", System.Type.GetType("System.Int32"))
 
 
        ' field properties
        fid.AllowDBNull = False
        fid.AutoIncrement = True
        fid.AutoIncrementStep = 2
 
        fkd.AllowDBNull = False
        fkd.MaxLength = 5
 
        fnm.AllowDBNull = False
        fnm.MaxLength = 50
 
        fkel.AllowDBNull = False
 
 
        dt.Columns.Add(fid)
        dt.Columns.Add(fkd)
        dt.Columns.Add(fnm)
        dt.Columns.Add(fkel)
        'create primary
        Dim uc As UniqueConstraint = New UniqueConstraint(fid)
        dt.Constraints.Add(uc)
 
        uc = New UniqueConstraint(fkd)
        dt.Constraints.Add(uc)
 
        Dim dtkey(2) As DataColumn
        dtkey(0) = dt.Columns("id")
        dtkey(1) = dt.Columns("kode")
 
 
        dt.PrimaryKey = dtkey
 
 
 
        Dim dr As DataRow
        
        For i As Integer = 1 To 20
            dr = dt.NewRow
            dr.Item("kode") = "A00" & i
            dr.Item("Name") = "SAMPLE KE " & i
            If i Mod 4 = 0 Then
                dr("idkel") = 1
            ElseIf i Mod 3 = 0 Then
                dr("idkel") = 3
            Else
                dr("idkel") = 2
            End If
            dt.Rows.Add(dr)
        Next
 
        ds.Tables.Add(dt)
 
            Dim fkid As New DataColumn("id", System.Type.GetType("System.Int32"))
        Dim fknm As New DataColumn("nmkel", System.Type.GetType("System.String"))
 
        Dim dt2 As New DataTable("dtkelompok")
 
        fkid.AutoIncrement = True
        fkid.AllowDBNull = False
 
        fknm.AllowDBNull = False
        fknm.MaxLength = 50
 
 
        dt2.Columns.Add(fkid)
        dt2.Columns.Add(fknm)
 
        Dim unik As UniqueConstraint = New UniqueConstraint(fkid)
 
        Dim pkk(1) As DataColumn
 
        pkk(0) = dt2.Columns("id")
        dt2.PrimaryKey = pkk
 
        Dim row As DataRow
        For i As Integer = 1 To 3
            row = dt2.NewRow
            row("nmkel") = "Category " & i
            dt2.Rows.Add(row)
        Next
 
        ds.Tables.Add(dt2)
 
 
        'relation 
        Dim dtRelation As New DataRelation("qcustomer", fkel, fkid, True)
        ds.Relations.Add(dtRelation)
    End Sub
End Class

i get error at line

ds.Relations.Add(dtRelation)

error message :

These columns don't currently have unique values.

[Shaggy Hiker]

It looks like you have your parent and child column names backwards.

[Tengkorak]

keep how is the solution?

If the code that I create properly?

[.paul.]

try this:

Dim dtRelation As New DataRelation("qcustomer", ds.Tables("dtCustomer").Columns(fkel), ds.Tables("dtkelompok").Columns(fkid), True)

[Tengkorak]

Thank you,

I try but still have not managed

[Shaggy Hiker]

What I was saying was that it looked like fkel is the child, while fkid looks like the parent. After all, fkid is a primary key, while fkel is not. Therefore, it looks like this:

Dim dtRelation As New DataRelation("qcustomer", fkel, fkid, True)

should be:

Dim dtRelation As New DataRelation("qcustomer", fkid, fkel, True)

[Tengkorak]

I've tried the way as above but still can not.
and I get an error message like this:

This constraint cannot be enabled as not all values have corresponding parent values.

at line

ds.Relations.Add(dtRelation)

[Tengkorak]

I've found the location of the fault.
it turns out there is a value of 0 in field idkel (child) while the value 0 is not found in the parent (id).

of the above conditions, would not it be if the value 0 is not contained in the parent.
what if there are conditions like this?

[Tengkorak]

i replace code be :

For i As Integer = 1 To 20
            dr = dt.NewRow
            dr.Item("kode") = "A00" & i
            dr.Item("Name") = "SAMPLE KE " & i
            If i Mod 4 = 0 Then
                dr("idkel") = 0
            ElseIf i Mod 3 = 0 Then
                dr("idkel") = 1
            Else
                dr("idkel") = 2
            End If
            dt.Rows.Add(dr)
        Next