I like the fact that AddOrUpdate let's you specify a filter to check to avoid adding duplicates. But I would like similar functionality without the update.
Right now I do something like this:
var checkProfile = from p in db.Profile
where p => p.LastName == newProfile.lastName
&& p => p.FirstName == newProfile.firstName
&& p => p.Middle== newProfile.middle
select p;
if (checkProfile.FirstOrDefault() == null)
{
db.Profile.Add(newProfile);
db.SaveChanges();
}
I know I can do something like this:
db.Profile.AddOrUpdate(p => new {p.LastName, p.FirstName, p.Middle}, newProfile);
db.SaveChanges();
But I would rather skip modifying the data in this case.
The first example does what I want but with more code. Is there a simpler/cleaner way to do what I want in the first example?
Update:
I like Ognyan Dimitrov's suggestion. I'm trying to implement it. My models inherit from BaseEntity. Can I put a generic version of that there?
My model is defined:
public class Address :BaseEntity
{
My BaseEntity:
public class BaseEntity
{
public virtual T AddIfNotExists<T>(T entity, Expression<Func<T, bool>> predicate = null)
{
var exists = predicate != null ? DbSet.Any(predicate) : DbSet.Any();
return !exists ? DbSet.Add(entity) : null;
}
}
I'm getting errors for Any(...) and Add(...). The error for Add(...) is 'An object reference is required for the non-static field, method, or property 'System.Data.Entity.DbSet.Add(object)' '
Should I be using this.Add(object) ?
Update 2:
I've created this code:
public static class DbSetExtensions
{
public static T AddIfNotExists<T>(this DbSet<T> dbSet, T entity, Expression<Func<T, bool>> predicate = null) where T : class, new()
{
var exists = predicate != null ? dbSet.Any(predicate) : dbSet.Any();
return !exists ? dbSet.Add(entity) : null;
}
}
Now I'm trying to call it like this, but it's not correct. Forgive my lack of understanding.
_db.ProfileIdentifier.AddIfNotExists(newIdentifier,
pi => new {pi.ProfileId, pi.ProfileIdentifierTypeId, pi.ProfileIdentifierValue});
Update - Solution:
I can call the DbSetextensions like this:
_db.ProfileIdentifier.AddIfNotExists(newIdentifier,
pi => pi.ProfileId == profileId &&
pi.ProfileIdentifierTypeId == (int)type &&
pi.ProfileIdentifierValue == value);
Thanks a lot for working with me Ognyan!!!
Have you tried to check if the entity exists and if not - add it? Like this :
UPDATE
using System.Linq.Expressions;
public class ContextWithExtensionExample
{
public void DoSomeContextWork(DbContext context)
{
var uni = new Unicorn();
context.Set<Unicorn>().AddIfNotExists(uni, x => x.Name == "James");
}
}
public static class DbSetExtensions
{
public static T AddIfNotExists<T>(this DbSet<T> dbSet, T entity, Expression<Func<T, bool>> predicate = null) where T : class, new()
{
var exists = predicate != null ? dbSet.Any(predicate) : dbSet.Any();
return !exists ? dbSet.Add(entity) : null;
}
}
You can use this method directly and remember to call DbContext.SaveChanges() after the call.