如何在各种条件下在mongodb中构建动态查询

Question

I have a sql query I need to make equivalent mongodb query I am using c# driver. Is it possible to create a dynamic method to create mongo equivalent of these kind of sql queries where I can specify dynamically what all columns should be taken with dynamically created where conditions. Please help to create mongo equivalent query using c#

SELECT distinct(employeeID), firstname, Lastname, salary, joinedOn FROM [Employees]
where salary >= 40000 and joinedOn between '2011/02/25' and '2012/02/27'

Answer 1

What about use Linq to build a dynamic query?

  public T findOne<T> (Expression<Func<T, bool>> expression) where T: class
    {
        var db = server.GetDatabase(databaseName);
        var documents = db.GetCollection<T>(typeof(T).Name);

        return (documents.AsQueryable<T>().Where(expression)).SingleOrDefault;
    }

You can use it in this way:

var employee = findOne<Employee>(e=> d.salary>=4000 &&
                                  d.joinedOn > "2011/02/25"  &&
                                  d.joinedOn < "2012/02/27");

I think you should convert joinedOn to DateTime.