A look at the code

#ifndef __body

#define __body

#include "tag.ddl"

class body : public ooObj {

public:

ooRef(Tag) tag <-> list[];

inline virtual char* identify() const =0;

inline virtual float GetVolume() const =0;

inline virtual float GetSurface() const =0;

};

#endif

#ifndef __tag

#define __tag

#include "PHTimeStamp.h"

#include <iostream.h>

class body;

class Tag: public ooObj {

public:

ooRef(body) list[] <-> tag;

Tag();

protected:

PHTimeStamp timestamp;

friend ostream & operator << (ostream &os, const Tag &tag);

};

ostream & operator << (ostream &, const Tag &);

#endif

This is the syntax for a bi-directional one-to-many happy relationship.

And here we make a Tag (key) object and give it 20 or so Body objects.

The green keywords are placement instructions, so we keep “keys” /Tags away from the data…

ooHandle(Tag) theTag;

theTag = new(dbTag) Tag();

ooHandle(body) cu,cy;

for (float x = 1; x < 5.; x += 0.5)

{

cu = new(dbH) cube(x);

cy = new(dbH) cylinder (x, x*2.);

theTag->add_list(cu);

theTag->add_list(cy);

}