unit Customer;
interface
uses
  Aurelius.Mapping.Attributes;

type
  [Entity, Automapping]
  TCustomer = class
  private
    FId: integer;
    FName: string;
  public
    property Id: integer read FId write FId;
    property Name: string read FName write FName;
  end;

implementation
end.

program GettingStarted;

{$APPTYPE CONSOLE}

uses
  Aurelius.Drivers.Interfaces,
  Aurelius.Drivers.SQLite,
  Aurelius.Engine.DatabaseManager,
  Aurelius.Engine.ObjectManager,
  Aurelius.SQL.SQLite,
  Customer;

var
  Connection: IDBConnection;
  Manager: TObjectManager;
  Customer: TCustomer;
begin
  Connection := TSQLiteNativeConnectionAdapter.Create('test.db');
  Manager := TObjectManager.Create(Connection);
  Customer := TCustomer.Create;
  Customer.Name := 'First customer';
  Manager.Save(Customer);
  Manager.Free;
  WriteLn('Customer saved.');
  ReadLn;
end.

procedure CreateDatabase(Connection: IDBConnection);
var
  DBManager: TDatabaseManager;
begin
  DBManager := TDatabaseManager.Create(Connection);
  DBManager.BuildDatabase;
  DBManager.Free;
end;

1. Wednesday, February 6, 2013 at 11:54:16 AM

In your sample code, is not the TCustomer instance leaking memory?

A. Bouchez

3. Thursday, February 7, 2013 at 5:43:43 AM

How does Aurelius handle updating objects?
Say for arguments sake that the customer table consists of just the name, but that name must be unique in the table. The ID field is no longer present (yes I realise this is bad design but I have seen it in client databases before).

So, you set your TCustomer object to have a name of ''First customer'' and save it. If you then changed that name to ''Second customer'', in the same object, and saved it, would Aurelius add a new record, or update the previous record to have a different name? How is this distinction handled in cases like this, or does it insist on having fixed ID fields that are always defined?

eg;

TCustomer = class
private
FName: string;
public
property Name: string read FName write FName;
end;

...

Customer := TCustomer.Create;
Customer.Name := ''First customer'';
Manager.Save(Customer);
Customer.Name := ''Second customer'';
Manager.Save(Customer);

Does it add a new record or update existing one, or error with ambiguity? Of course, in real code you would do what was appropriate for the task, but I am curious as to how Aurelius handles these edge cases.

The reason I ask is that, for example you need to import data from an external source, and you have to make that distinction between updating and adding. How can you control Aurelius to do this ''neatly'' if you do not know the ID field before (or there isn''t one available)? Will it handle this gracefully, or is there some nifty way of ensuring it ''just knows'' when to update or add a record?
What happens if you do this:

Customer := TCustomer.Create;
Customer.Name := ''First customer'';
Manager.Save(Customer);
Customer.Name := ''First customer'';
Manager.Save(Customer);

Will Aurelius ignore the second save due to no changes, will it add another record, does it read the metadata to determine if duplicates of the Name field would be allowed and then add a new copy? Or can you define when it does each? If possible, how easy/messy is it to define these rules?

I''m really curious because I have written an ORM framework before (even using attributes in a similar way to your example above) and when dealing with poorly set up databases it can sometimes be challenging to remove ambiguities with ''generic'' ORM code.
Looking forward to hearing your response, and FWIW if Aurelius was around before I''d rolled my own I probably would have used that instead :)

Scalea

5. Thursday, February 7, 2013 at 6:19:32 AM

Thanks for your super-quick response!
That''s good to know, I have one last question:
Can Aurelius handle multiple unique fields, for example if you had a table with ID1, ID2 and ID3 and all must remain unique? I would imagine you''d just define more IDs but I have to check ;)

Thanks for your reply, I must say it looks like an impressive and adaptable framework.

Scalae

7. Saturday, March 30, 2013 at 4:03:49 AM

1. In documentation the TDataBaseManager.UpdateDatabase method is described, but such method doesn''t exist. Why?
2. You plan to implement support of the stored procedures in Aurelius?

Shevjakov Vladislav