C#•2w ago

Is it possible to remove a many-to-many relationship without using `Include` in EF Core?

Let's say there is a many-to-many relationship between A and B, and an entity a of type A with an ID of 1 is related to an entity b of type B with an ID of 2. Is it possible to remove this relationship without using context.A.Include(a => a.Bs)... or an explicit join table?

7 Replies

Angius•2w ago

What do you mean "remove it"? .Include certainly does not remove any relationships

palapapaOP•2w ago

Basically I want to remove a row in the join table where the AId column is 1 and the BId column is 2 The only way I know is to use Include to populate the collection navigation property of A first, then remove the B instance with an ID of 2 from it, then call SaveChanges

Angius•2w ago

var j = await context.Joins
    .Where(jt => jt.AId == a && jt.BId == b)
    .FirstOrDefaultAsync();
context.Joins.Remove(j);
await _context.SaveChangesAsync();

var j = await context.Joins
    .Where(jt => jt.AId == a && jt.BId == b)
    .FirstOrDefaultAsync();
context.Joins.Remove(j);
await _context.SaveChangesAsync();

await context.Joins
    .Where(jt => jt.AId == a && jt.BId == b)
    .ExecuteDeleteAsync();

await context.Joins
    .Where(jt => jt.AId == a && jt.BId == b)
    .ExecuteDeleteAsync();

would work

palapapaOP•2w ago

I don't want to use an explicit join table

Angius•2w ago

Tough

Anton•2w ago

You should be able to There should be shadow properties for this stuff And you can get the table by name Or from a relationship

Angius•2w ago

If you have a property referencing the JoinTable, sure But that would require that JoinTable to exist in code Ergo, explicit join table one way or another

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Is it possible to remove a many-to-many relationship without using `Include` in EF Core?

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