How to insert two or more different values under one column name based on parent PK?

Are you talking about a DataTable? Although a DataTable column cannot have multiple values, a Primary Key can be created from multiple columns.

Sub Main()
    Dim dt As New DataTable()
    dt.Columns.Add("KEY1")
    dt.Columns.Add("KEY2")
    dt.Columns.Add("Item")
    dt.PrimaryKey = New DataColumn() {dt.Columns("KEY1"), dt.Columns("KEY2")}
    dt.Rows.Add("1", "1", "A")
    dt.Rows.Add("1", "2", "B")
    dt.Rows.Add("1", "1", "C") ' System.Data.ConstraintException
End Sub

Reason is multiple entries under the same primary key combination, which is causing a System.Data.ConstraintException due to the primary key constraint you defined. In a DataTable, each primary key combination must be unique, which is why you're seeing that error.

Different approach

Use a Separate Table: Instead of trying to insert multiple values into the same DataTable, you could create a separate DataTable to manage the multiple entries. The primary table can reference this table using foreign keys.

Use Composite Key: If every unique combination is required but the actual "item" values vary, consider creating a composite key in your DataTable that includes additional columns to differentiate items.

Hope you're doing well , we're following up on the ticket. Please let us know issue persist are resolved.