查询或合并一对多关系，而无需重复结果条目

Question

I have 2 very large data sets. The first "Main Table" is a unique list. The second "Reference Table" is a one-to-many relationship with the "Main Table".

Objective: Query with filters across both data sets but display the results without duplicating the entries of the "Main Table". I don't want the user to scroll through 200 rows of the same line item just because the fields of the one-to-many "Reference Table" are highly unique.

Are there any techniques to deal with this?

All I can think of is sequentially appending the rows of the "Reference Table" as Columns to the "Main Table", like; a_1, b_1, a_2, b_2,...

Here is an example of the data sets: data

I'm working with C#, ASP.NET, SQL Server 2016, Entity Framework

Answer 1

You can get a lot of functionality by splitting your query into two parts:

using (MainContext ctx = new MainContext()) {
  var rows =  from main in ctx.Main
              select new 
              {
                Main = main,
                References = from r in ctx.References
                             where r.Id == main.Id
                             select r
              }

  // Do something with your rows
}

This will send one query to the DB and return one entity per row in Main , with a separate property that will contain all of that Main row's metadata.

IF you send this back to client using, for example, a WebAPI call, the data on the client would look like:

[{
  main: { id: ..., x: ..., y: ..., z: ...},
  references: [{ a: ..., b: ... }, {a: ..., b: ... }, ... ]
},
...,
]