Tag - code-first - Synopse Open Source

Introducing mORMot's architecture and design principles

We have just released a set of slides introducing ORM, SOA, REST, JSON, MVC, MVVM, SOLID, Mocks/Stubs, Domain-Driven Design concepts with Delphi, and showing some sample code using our Open Source mORMot framework. You can follow the public link on Google Drive! This is a great opportunity to […]

ORM mapping class fields to external table columns

When working with an ORM, you have mainly two possibilites:

Start from scratch, i.e. write your classes and let the ORM creates all the database structure - it is also named "code-first";
From an existing database, you define in your model how your classes map the existing database structure - this is "database-first".

We have just finalized ORM external table field mapping in mORMot, using e.g.
aModel.Props[aExternalClass].ExternalDB.MapField(..)
See this last commit.

So you can write e.g.

fProperties := TSQLDBSQLite3ConnectionProperties.Create(
  SQLITE_MEMORY_DATABASE_NAME,'','','');
VirtualTableExternalRegister(fExternalModel,
  TSQLRecordPeopleExt,fProperties,'PeopleExternal');
fExternalModel.Props[TSQLRecordPeopleExt].ExternalDB.
  MapField('ID','Key').
  MapField('YearOfDeath','YOD');

Then you use your TSQLRecordPeopleExt table as usual from Delphi code, with ID and YearOfDeath fields:

The "internal" TSQLRecord class will be stored within the PeopleExternal external table;
The "internal" TSQLRecord.ID field will be an external "Key: INTEGER" column;
The "internal" TSQLRecord.YearOfDeath field will be an external "YOD: BIGINT" column;
Other internal published properties will be mapped by default with the same name to external column.