Omar AL Zabir blog on ASP.NET Ajax and .NET 3.5

# re: Linq to SQL: Delete an entity using Primary Key only

I did something similar but as extension method of Table<TEntity>. I think should be mentioned that if DataContext is not readonly then  single item query can return cached entity.

# re: Linq to SQL: Delete an entity using Primary Key only

Can't you just attach a constructed object to the datacontext and then call DeleteOnSubmit.

Entity ent = new Entity();

Entity.pk = 1;

datacontext.Attach(ent);

datacontext.Entity.DeleteOnSubmit(ent);

# re: Linq to SQL: Delete an entity using Primary Key only

No! doing so will simply raise row not found or some thing similar as the data is not matched...

"Can't you just attach a constructed object to the datacontext and then call DeleteOnSubmit.

Entity ent = new Entity();

Entity.pk = 1;

datacontext.Attach(ent);

datacontext.Entity.DeleteOnSubmit(ent);"

# re: Linq to SQL: Delete an entity using Primary Key only

This is great. I have run into this problem so many times but have just dealt with it on a case by case basis. A generic solution is very slick.

# re: Linq to SQL: Delete an entity using Primary Key only

Not sure I'm a fan...

# re: Linq to SQL: Delete an entity using Primary Key only

This will fail with composite keys but more worryingly is open to SQL injection in the DeleteByPK function where the key is a string.

You should be very very careful about building SQL out of strings.

[)amien

# re: Linq to SQL: Delete an entity using Primary Key only

Can you write similar function for Update?

# re: Linq to SQL: Delete an entity using Primary Key only

Great post.  Definately a little helper I'll add to my current list of L2Q extension methods (with a bit of a variation).  Anyway, you can see my post at www.aneyfamily.com/.../Batch-Updates-and-Deletes-with-LINQ-to-SQL.aspx to see how I do batch updates and deletes.

# re: Linq to SQL: Delete an entity using Primary Key only

Omar: on a different subject, I downloaded your DropThings project on CodePlex but the database file/scripts are missing.

# re: Linq to SQL: Delete an entity using Primary Key only

Good solution and its very helpfull.

# re: Linq to SQL: Delete an entity using Primary Key only

Are we going back to writing convoluted SQL code by using LINQ? The whole idea was to get away from that.

# re: Linq to SQL: Delete an entity using Primary Key only

Add this to your datacontext and you'll be able to delete in a much more performant way

like:

dataContext.Delete(dataContext.Threads.Where(x=>x.ThreadId == threadId));

public int Delete<T>(IEnumerable<T> entities)

{

System.Data.Common.DbCommand command = this.GetCommand(entities.AsQueryable());

string s = this.GetCommand(entities.AsQueryable()).CommandText;

command.CommandText = "DELETE [t0]\r\n" + s.Substring(s.IndexOf("FROM"));

command.Connection.Open();

int records = command.ExecuteNonQuery();

command.Connection.Close();

return records;

}

thanks to my colleague Evaldas :)

# re: Linq to SQL: Delete an entity using Primary Key only

smnbss - That code could get you into trouble if your entities IQueryable is built from joining two tables.  See a more reliable way of deleting at www.aneyfamily.com/.../Batch-Updates-and-Deletes-with-LINQ-to-SQL.aspx.

# re: Linq to SQL: Delete an entity using Primary Key only

This is one solution to avoid roundtrip, you can use store procedure to delete particular entity without roundtrip (If it is a big performance issue in your app).

# re: Linq to SQL: Delete an entity using Primary Key only

Very nice! I've used this and it works perfectly!

Thanks!!!

# re: Linq to SQL: Delete an entity using Primary Key only

you should not do the reflection yourself.

What about

table.Context.Mapping.GetTable(typeof(TTable)).TableName

# re: Linq to SQL: Delete an entity using Primary Key only

Great Post! Do you have any idea how we can do the same thing for tables with more than one primary key?

# Linq to SQL: Delete an entity using Primary Key only

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