Question

In a c#.net application I have a two classes as below

Employee

EmployeeId : int : Primary key

Name : string

Job

JobId : int : Primary key

Name : string

EmployeeId : int

In database (SQL Server) I have two tables to save data from those classes (Employee & Job)
(ID fields are auto increment fields so can have same no in both tables)

Now I need to implement a new feature to give users to add comments for Employees or for Jobs, So I need to create a single Comment class to share by both classes.

What is the best Class & Table Structure to implement this new feature.

Answer 1

I’d recommend a database design like which allows adding more comment types in the future without the need to modify your database.

Table Comment

Id (int, Primary Key)
CommenteeId (int, not null)
CommentTypeId (int, not null)
Text (nvarchar(255))

Table CommentType

Id (int, Primary Key)
Name (nvarchar(50), not null)

CommenteeId will reference Job or Employee or any other table you’d need to comment in the future.

CommentTypeId will reference CommentType where you can add types as needed.

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As for your class design it could look like this:

public class Job
{
    public List<Comment> Comments;
    public string Name { get; set; }
}


public class Employee
{
    public List<Comment> Comments;
    public string Name { get; set; }
}

… as a basic idea. How and when your Comment is loaded as part of Employee or Job is depending on your method of accessing your database.