parent-child relationship

[shantha05]

How can I create business classes interlinking two tables (parent-child relationship)

[mgnoonan]

The easiest way is to create a View with the two tables linked. You can then set the QuerySource of one of the related objects to the name of the view and do a Query.Load().

See:
http://www.easyobjects.net/Tutorials/BuildingQueries/tabid/118/Default.aspx#QuerySource

Or you can generate a new business object for the view using the Business View template.

[shantha05]

Thanks

[TimGSXR]

So say I have the table User->User_Role->Role I want in my business entity to be able to do User.Roles so if I understand this correctly in my User class i should be able to set up the Roles property for user like so.

public Role Roles
{
get
{
Role roles = new Role;
role.QuerySource = \"vUserRoles\";
role.Where.UserId.Value = this.Id;
role.Query.Load();
return role;
}
}

The problem is the schema for Role does not include the UserId column, the UserId column is grabbed in the view, how will this work?

[sbc]

You could use Filter:

Code: Select all

Role roles = new Role;
role.QuerySource = \"vUserRoles\";
role.Query.Load();
role.Filter = 'UserId=' + this.Id;
return role;

Although you would load all the data in the view first (if there is not a lot of data, then that is not really a problem). Of course including the Id in the view (with the same column name as in the table) would be a better way.

[mike.griffin]

Actually, I think Matt meant for you to create a View then generate an EasyObject off of that?

[mgnoonan]

Mike is correct. I was suggesting you generate a business object from the view, that way you have typed properties and WhereParameters for all the columns in the view.

[TimGSXR]

but you can't do AddNew with a view can you?

What I really need is a way to get the object representing the table from the superset object i.e.

get the business view object(superset of Role + UserId) using where clause from view

UserRoles userroles = new UserRoles;
userroles.Where.UserId.Value = this.Id;
userroles.Query.Load();

from the superset business view object get a standard Business object based on the Role table
Role role = userrole;

Then i'd have the best of both worlds, I thnk.

Cheers

Tim

[mike.griffin]

I think then SBC's recommendation is the way to go, in dOOdads I know you can trick your table based object to load itself from a view that way you can still save it.

[mgnoonan]

And EO gives you the same capability. Just set the QuerySource as sbc suggested. You don't have to use the Filter property if you don't want, you can add a Where clause to your query that will only retrieve the UserID you are after.

[TimGSXR]

ok thats great giving it a go now.

thanks for the help, EasyObjects rock!

[mgnoonan]

Thanks! Keep me posted on how your project is going!