How to filter specific columns from a child table Entity Framework

Question

I have 3 tables with 1:many parent child relation

• TableA
• TableB (child of TableA)
• TableC (child of TableB)

I am able to retrieve all of the data from these tables with query

var data = dbContext.tableA.where(a => a.ID == rowID)
           .Include(a => a.tableB.Select(n => n.tableC)).SingleOrDefault();

For TableC , I don't want all of the columns to be retrieved from database. I just want ID, TableC_FK columns data to be retrieved for TableC .

How do I do that?

Answer 1

I think you cannot project into TableA unless you have scheme that support it. IMHO The best option is either anonymous project or Use Viewmodel/DTO suggested by @jpgrassi

You can use anonymous here, more tutorial of anonymous projection here

var data = dbContext.tableA
                    .where(a => a.ID == rowID)
                    .Select(tableA=> new 
                    {
                       firstColumn = tableA.FirstColumn,
                       tableC = tableA.SelectMany(tableB=>tableB.TableC),
                    }.SingleOrDefault();