WCF with Entity Framework Code First - entity-framework

Question

I want to use EF behind my WCF service to fetch data and display it to the client. I need the following suggestions:
Do I need to have the same interface for all the views (e.g. students, teachers etc.) or do I need to have a different interface and service for every table (or view)
Do I need to generate the database calls within my service (.svc) or some other architecture is preferred?
public Student[] GetAllStudents()
{
//database generation code here
}
How can I use EF code-first approach to generate database. I know that for an MVC app, you need to set the initializer in Global.asax or in web.config but I am not sure how it's called in this case. My model looks like this:
[DataContract]
public class Student
{
[DataMember]
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[DataMember]
public string Type { get; set; }
[DataMember]
public string Subject { get; set; }
[DataMember]
public string Description { get; set; }
}

Answer 1

What you really should do is break up your system in to more separate layers. Instead of having a WCF call that directly queries the database, create a "buisness logic" layer that translates the information that the WCF call provides you to what the EF call needs to know. This is called a N-Tier application
public class SchoolAPI : ISchoolAPI
{
private DataAccessLayer _dal = new DataAccessLayer();
public Student[] GetAllStudents()
{
return _dal.GetStudents(null, null);
}
public Student[] GetAllScienceStudents()
{
return _dal.GetStudents(null, DataAccessLayer.ScienceStudentType);
}
}
private class DataAccessLayer
{
public static readonly ScienceStudentType = //...
public Student[] GetStudents(string subject, string type)
{
using(var ctx = new SchoolContext())
{
IQueryable<Student> studentQuery = ctx.Students;
if(subject != null)
studentQuery = studentQuery.Where(s=>s.Subject == subject);
if(type != null)
studentQuery = studentQuery.Where(s=>s.Type == type);
return studentQuery.ToArray();
}
}
}
The caller of the WCF call does not need to know what the string ScienceStudentType is, all it cares about is that it gets the science students. By seperating the business logic from the database call the caller of your service no longer needs to know.
For EF it will initialize on the first time the framework goes out to "touch" the database and detects that it is not there if it is set up to do so. This is done in the constructor of SchoolContext but is getting a little too broad for this answer. I recommend finding a tutorial on EF and get it working in a simple test enviorment without WCF (maybe a simple console app that just calls GetStudents() then move in in to a WCF environment.