selective get and delete posts from database

Question

In my windows phone 7 app i have database-class generated by sqlmetal. in addition, i have class that helps to work with this database.

    public static IList<Task> GetTasks()
    {
        IList<Task> tasks = new List<Task>();
        using (var context = new MyDBContext(ConnectionString))
        {
           tasks = (from emp in context.Tasks select emp).ToList();
        }
        return tasks;
    }

this code return all posts from the database.

My questions:

• 1) How I can get posts, for example, only with a specific date (datetime) or ID(int)?
• 2) Is there any way to delete posts from the database?

Answer 1

Try this:

tasks = from emp in context.Tasks 
        where emp.ID == yourId
        select emp;

To delete posts from te databse use DeleteOnSubmit(entity) method like:

context.Tasks.Attach(entityToDelete);
context.Tasks.DeleteOnSubmit(entityToDelete);
context.SubmitChanges();

Answer 2

1) You should add 'where' to your LINQ statement. Like this:

from emp in context.Tasks select emp where emp.Date == new DateTime(2011, 11, 11)

2) To delete posts from database you should do three simple steps:

1. Get posts you want to delete from db

   tasks = from emp in context.Tasks select emp where emp.Date > new DateTime(2011, 11, 11)

2. Call DeleteAllOnSubmit method of your DataContext object with our tasks to delete

   dbContext.DeleteAllOnSubmit(tasks);

3. Call SubmitChahges method of your DataContext object.

   dbContext.SubmitChanges();