2. Developping with Objy (overview)

Objy permits you to develop database applications written in C++. A given application can handle only one Federation. The usual steps to do that are the following:
 

1. Create your Federated Database with the administration tool oonewfd (see 3. Objy Adm. tools).
2. Design your data model: Identify the objects of your application header files (.h) that you want to be persistent and make them inherit from the ooObj class: e.g. if you take a look at PHENIX PdbObjyCalBank file you find things like: class PdbObjyCalBank : public ooObj, public PdbCalBank { ...};
3. Rename the header files to .ddl [the Data Definition Language DDL is basically C++ plus a few syntactic extensions for things like object relationships through "to-one"/"to-many" associations ...]. Those DDL files contain persistence-capable class declarations and associations among them.

Replace C++ pointers by DDL object references.
4. Preprocess your DDL data model files with ooddlx. The prepocessor ooddlx generates i) the database schema (myschema.ddl) which is also added to the system Federation file; and ii) the headers (MyApp.h and MyApp_ref.h) and code (MyApp.cxx) files which make the schema (the information about an object which the database must maintain) available to your C++ application. (From there on, your database will "know" about the type of your objects).
5. Now you can complete the source code for your application (one uses standard functions like e.g. ooref(myclass) and oohandle(myDB) to interact with Objy persistent objects and perform database operations ...).
6. Compile your C++ application source file (e.g. PHENIX PdbObjyApplication.hh and PdbObjyApplication.cc) and the data model source files (e.g. PHENIX PdbObjyCalBank).
7. Link your compiled application code and compiled data model code with Objy runtime libraries.

To know more precisely how to add your own classes to an Objy database take a look at 5. Adding your own classes to the PHENIX Federation.