Question

I have a simple class:

public class User : ActiveRecordLinqBase<User>
{
    [PrimaryKey(Column = "user_id", Length = 20)]
    public string Id { get; set; }

    [Property(Column = "password", Length = 16)]
    public string Password { get; set; }
    ...
}

and I have created the following repository:

public class SqlRepository<T> : IRepository<T> where T : ActiveRecordLinqBase<T>, new() {
    public void Add(T entity) {
        entity.SaveAndFlush();
    }

    public void Remove(T entity) {
        entity.DeleteAndFlush();
    }

    public void Modify(T entity) {
        entity.UpdateAndFlush(); ;
    }

    ...

    public IEnumerable<T> FindAll(Func<T, bool> predicate) {
        return ActiveRecordLinqBase<T>.Queryable.Where(predicate);
    }
}

Now, when running the following unit test (against a MySQL database):

[Test]
public void Test_Sample() {
    var repo = new SqlRepository<T>();
    repo.Add("john.doe", "keyword1");
    repo.Add("other.user", "keyword2");

    var users = repo.FindAll(x => x.Username.Contains("john")).ToList();

    Assert.AreEqual(1, users.Count);
}

… I get the following SQL query:

SELECT this_.user_id as user1_0_0_, this_.password as password0_0_, this_.role as role0_0_ FROM users this_

Where is the WHERE clause?

If I instead do the following in the same test directly…

var users = User.Queryable.Where(x => x.Username.Contains("john"));

I get the following SQL:

SELECT this_.user_id as user1_0_0_, this_.password as password0_0_, this_.role as role0_0_ FROM users this_ WHERE this_.user_id like ?p0;?p0 = ‘%john%’

Am I doing something wrong?

What is the difference between those two queries?

---

Edit: I also tried with

return ActiveRecordLinq.AsQueryable<T>().Where(predicate);

without success.

Answer 1

Now this is just because I like code, and sometimes I notice stuff… I’m no expert on Active Record, so this is just a guess…

Maybe you should change the signature of the FindAll method from

public IEnumerable<T> FindAll(Func<T, bool> predicate)

into

public IEnumerable<T> FindAll(Expression<Func<T, bool>> predicate)

which will allow you to hit the right overload of Where, which is most likely the overload you’re looking for.

It’s because a Func can’t be reflected upon the same way an Expression of Func can.