LINQ, Lambda, and Generics: Insert and Delete
8/10/2007 6:35:26 PM
I think I'm addicted. Aside from my first LINQ application ("Hello AccountTypeId") I haven't written one SQL-like query. From that point on everything has been done with Generics, Lambda expressions (Expression<> trees), and starting today: Reflection. In the past I tried very hard not to have any SQL or SQL-like syntax in code so why should I start now? Maybe I'll come around. Personally I think using Generics coupled with Expression<> trees and Reflection makes for much more elegant code but that is just me. :-)
I, like others I'm sure; am just waiting to see how LINQ is going to play into this whole Presentation / Business / DataAccess layer scheme. I can't find it right now but I do have a great link (2) to post discussing developer speculations on what is to become of a 3-tier architecture.
Anyway, some more code that I've been working on.
public
static void Insert<T>(T entity) where T : class
{
using (OrcasDB database = new OrcasDB())
{
database.GetTable<T>().Add(entity);
database.SubmitChanges();
}
}
public static void Delete<T>(Expression<Func<T, bool>> predicate)
where T : class
{
using (OrcasDB database = new OrcasDB())
{
T instance = (T) database.GetTable<T>().Where<T>(predicate).Single();
database.GetTable<T>().Remove(instance);
database.SubmitChanges();
}
}
How to Use
// insert
Employee will = new Employee
{
Username = "will.asrari",
EmailAddress = "me@willasrari.com",
CanCode = true
};
LinqHelper.Insert<Employee>(will);
// delete
LinqHelper.Delete(emp => emp.EmployeeId.Equals(3));
Easy. My Delete<T> method could probably be made more elegant but this code does work.
UPDATE
I found the links that I wanted to post. Pretty lengthy, but some interesting reading.
Creating a DAL with Linq to Sql Part 1
Creating a DAL with Linq to Sql Part 2
LINQ,
Orcas
