CODEWITHSUNDEEP
c#entity-frameworkdatabase-performance
Pierre
Pierre

Reputation: 330

Reduce database calls with Entity Framework

Would it be possible to write this in 1 statement (make only 1 db call?) and still be able to differentiate between "The member did not exist" and "The member did exist but had no dogs".

public IEnumerable<Dog> GetDogsOfMember(int id)
{
    if (dbContext.Members.Any(i => i.ID == id))
    {
        return dbContext.Dogs.Where(i => i.Member.ID == id);
    }

    return null;
}

Upvotes: 3

Views: 969

Answers (1)

haim770
haim770

Reputation: 49095

If each Dog already contains a reference to the Member, you can expose the other end of the relationship (if you didn't already):

public class Member
{
    public int ID { get; set; }
    // ...
    public virtual ICollection<Dog> Dogs { get; set; }
}

Then you can issue a single efficient query using Include():

public IEnumerable<Dog> GetDogsOfMember(int id)
{
    var memberWithDogs = dbContext.Members
                                  .Include(i => i.Dogs)
                                  .SingleOrDefault(i => i.ID == id);

    if (memberWithDogs != null)
        return memberWithDogs.Dogs;

    return null;
}

Upvotes: 5

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