How to set DataColumn.Expression for DataRelation?

Question

.NET

Hello. There is an object theDataSet.
it has 2 tables:
Users:
Id, Name
Operations:
User_Id, Date, Description
Tables are linked using DataRelation
DataRelation theDataRelation = new DataRelation("Name",
Id_DataColumn_In_Users, User_Id_DataColumn_In_Operations)
theDataSet.Relations.Add(theDataRelation);
So, I want to add a calculated column to theDataSet.Tables["Operations"] that would show the username from Users.Name based on Users.Id and theDataRelation
PS Tips like "do it in the query" do not work, because I have there is only a ready-made DataSet, I do not get it directly from the database.
ZZY Tips, such as "do it with pens" do not fit. Before that, I would have thought of it myself, but I don’t want to go through a cycle of dohrena rows to insert the name I need throughout the new column, for this there are calculated columns using DataColumn.Expression, which calculate the value when accessed.

Answer 1

Understood. In Expression, you need to specify "parent(relation name).Column_Name"