C#•5d ago

✅ Implementing delete repository method & controller | Web Api

I would love to know how to properly implement delete repository method, in particularly how to handle possible null values.

16 Replies

Sehra•5d ago

$details

MODiX•5d ago

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Pobiega•5d ago

In the simplest case, trying to delete something that doesnt exist isn't actually an error, as the end result is the same: the item doesn't exist. So if you are trying to write idempotent code, if the query doesnt delete anything, thats fine.

workaniOP•5d ago

So this code is just about fine?

public async Task DeleteByIdAsync(int id)
{
    var comment = await context.Comments.FindAsync(id);

    context.Comments.Remove(comment!);
    
    await context.SaveChangesAsync();
}

public async Task DeleteByIdAsync(int id)
{
    var comment = await context.Comments.FindAsync(id);

    context.Comments.Remove(comment!);
    
    await context.SaveChangesAsync();
}

Angius•5d ago

Or better,

public async Task DeleteByIdAsync(int id)
{
    _ = await context.Comments
        .Where(c => c.Id == id)
        .ExecuteDeleteAsync();
}

public async Task DeleteByIdAsync(int id)
{
    _ = await context.Comments
        .Where(c => c.Id == id)
        .ExecuteDeleteAsync();
}

Or better yet, don't use repositories

Pobiega•5d ago

Absolutely not. save changes when nothing was done is silly. doing DbSet.Remove(null) is silly. if you know its null, just stop there. that said, ZZZZZZZZs code is much nicer and more performant its a single query, instead of two

workaniOP•5d ago

I like it

FusedQyou•5d ago

Not that the result value of SaveChangesAsync also indicates if something was deleted at all in this case I assume the same happends with ExecuteDeleteAsync

Angius•5d ago

FusedQyou•5d ago

It returns rows modified, so anything above 0 means there were changes

Angius•5d ago

It returns the amount of rows affected Same for .ExecuteUpdateAsync()

FusedQyou•5d ago

Yeah, affected is a better word

workaniOP•5d ago

Could you explain please meaning of '_ ='

Angius•5d ago

A discard Could as well be

public async Task DeleteByIdAsync(int id)
{
    await context.Comments
        .Where(c => c.Id == id)
        .ExecuteDeleteAsync();
}

public async Task DeleteByIdAsync(int id)
{
    await context.Comments
        .Where(c => c.Id == id)
        .ExecuteDeleteAsync();
}

But using a discard explicitly states "I know this method returns something, but I don't care"

workaniOP•5d ago

Thanks

Angius•5d ago

A matter of preference, really How explicit you want to be

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✅ Implementing delete repository method & controller | Web Api

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