Object Relational Mapping is the idea of being able to write queries using the object-oriented paradigm in your preferred programming language. So this means we are trying to utilize our language to talk with the database instead of using SQL.
Why utilize ORM?
- It abstracts away the database system, so switching is easy.
- Your queries can be efficient than writing them with SQL.
- With ORM, you get lots of features out of the box for instance
- Transactions
- Migrations
- Seeds
- Streams
- Connection Pooling
Delphi community has several Delphi ORM libraries, and the DORM (Delphi ORM) by Daniele Teti is one of the popular and open-source libraries you can use.
DORM has many features available:
- Database agnostic (Do not require database changes!)
- Has one, has many, and belongs to relations support
- Mapping through file, attributes, or CoC
- Save and retrieve objects graph, not only single objects
- External (file) or internal (resource, json stream) configuration
- Interfaces based!
- FirebirdSQL (using UIB)
- Interbase (using UIB)
- SQLServer (using FireDAC driver)
- SQLite3 (using this SQLite3 wrapper
- and more!
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procedure ObjVersionConcurrentTransactionsDEMO; var dormSession, dormSession1, dormSession2: TSession; Customer, C1, C2: TCustomerV; id: Integer; begin dormSession := TSession.CreateConfigured( TStreamReader.Create(CONFIG_FILE), TdormEnvironment.deDevelopment); try Customer := TCustomerV.Create; Customer.Name := 'Daniele Teti Inc.'; Customer.Address := 'Via Roma, 16'; Customer.CreatedAt := date; dormSession.Persist(Customer); id := Customer.id; WriteLn('Version: ', Customer.ObjVersion); dormSession.Commit(true); finally dormSession.Free; end; // read the same object twice dormSession1 := TSession.CreateConfigured( TStreamReader.Create(CONFIG_FILE), TdormEnvironment.deDevelopment); try dormSession2 := TSession.CreateConfigured( TStreamReader.Create(CONFIG_FILE), TdormEnvironment.deDevelopment); try // Two users gets the same record WriteLn('User1 loads object ' + inttostr(id) + ' and close transaction'); C1 := dormSession1.Load<TCustomerV>(id); dormSession1.Commit; WriteLn('User2 loads object ' + inttostr(id) + ' and close transaction'); C2 := dormSession2.Load<TCustomerV>(id); dormSession2.Commit; // First user update the object and save it C1.Name := 'John Doe'; C1.ObjStatus := osDirty; WriteLn('User1 update object ' + inttostr(id)); dormSession1.Persist(C1); dormSession1.Commit; // The second user try to do the same C2.Name := 'Jane Doe'; C2.ObjStatus := osDirty; WriteLn('User2 try to update object ' + inttostr(id) + ' (an exception will be raised)'); dormSession2.Persist(C2); // raise EDORMLockingException finally dormSession2.Free; end; finally dormSession.Free; end; end; |
Here you can download the Delphi ORM!
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Hi eveeyone. My name is Marcelo.
I am a Newbye in delphi.
Please, my question tag is.
Dorm is a Delphs native ORM?
TANKS
If I understand your question correctly you are asking “is Dorm an ORM system written in Delphi” – the answer is yes.