testtrav.cpp

实现内存数据库的源代码

//-< TESTTRAV.CPP >-------------------------------------------------*--------*
// FastDB                    Version 1.0         (c) 1999  GARRET    *     ?  *
// (Main Memory Database Management System)                          *   /\|  *
//                                                                   *  /  \  *
//                          Created:     15-Jan-99    K.A. Knizhnik  * / [] \ *
//                          Last update: 15-Jan-99    K.A. Knizhnik  * GARRET *
//-------------------------------------------------------------------*--------*
// Test of record traverse mechanism and set operations
//-------------------------------------------------------------------*--------*

#include <stdio.h>
#include "fastdb.h"
#include "set.h"

class Detail { 
  public: 
    char const*name;

    enum DetailClass { 
	dcResistor,
	dcTransistor,
	dcCondenser,
	dcDiode,
	dcBoard
    };
	
    dbSet<DetailClass> type;

    dbReference<Detail>             assembly;
    dbArray< dbReference<Detail> >  parts;

    TYPE_DESCRIPTOR((KEY(name, HASHED|INDEXED), 
		     RELATION(assembly, parts), 		     
		     RELATION(parts, assembly),
		     FIELD(type)));
    
    void print() const;
};

REGISTER(Detail);


dbSet<Detail::DetailClass> inputDetailClass()
{
    char buf[64], *type = buf;
    printf("Specify detail class(es)\n"
	   "\tr - resistor\n"
	   "\tt - transistor\n"
	   "\tc - condenser\n"
	   "\td - diode\n"
	   "\tb - board\n"
	   "? ");

    scanf("%s", type);
    dbSet<Detail::DetailClass> set;
    while (*type != '\0') { 
	switch (*type++) { 
	  case 'r':
	    set += Detail::dcResistor;
	    break;
	  case 't':
	    set += Detail::dcTransistor;
	    break;
	  case 'c':
	    set += Detail::dcCondenser;
	    break;
	  case 'd':
	    set += Detail::dcDiode;
	    break;
	  case 'b':
	    set += Detail::dcBoard;
	    break;
	  default:
	    printf("Invalid detail class: %c\n", *(type-1));
	    return set;
	}
    }
    return set;
}
	
void Detail::print() const
{ 
    printf("detail %s (", name);
    if (type.has(dcResistor)) { 
	printf("resistor ");
    }
    if (type.has(dcTransistor)) { 
	printf("transistor ");
    }
    if (type.has(dcCondenser)) { 
	printf("condenser ");
    }
    if (type.has(dcDiode)) { 
	printf("diode ");
    }
    if (type.has(dcBoard)) { 
	printf("board ");
    }
    printf(")\n");
}

int main() 
{ 
    dbDatabase db;
    if (db.open("testtrav")) { 
	dbReference<Detail> assembly;
	dbArray< dbReference<Detail> > parts;
	dbCursor<Detail> cursor;
	Detail detail;
	const int bufLen = 256;
	char name[bufLen];
	char newName[bufLen];
	dbSet<Detail::DetailClass> type;
	dbQuery q1, q2, q3, q4;
	bool notEmpty = cursor.select() > 0;

	q1 = "name=",name;
	q2 = type >= "type","start from",parts,"follow by parts";
	q3 = "start from",parts;
	q4 = "start from",assembly,"follow by assembly";

	detail.name = newName;

	while (true) { 
	    printf("\nMenu:\n"
		   "1. Add detail\n"
		   "2. Search for details\n"
		   "3. All details\n"
		   "4. Assembly parts\n"
		   "5. Part of\n"
		   "6. Exit\n>> ");
	    
	    int choice = 0;
	    
	    scanf("%d", &choice);
	    switch (choice) { 
	      case 1:
		if (notEmpty) { 
		    printf("Enter assembly name: ");
		    scanf("%s", name);
		}
		printf("Enter new detail name: ");
		scanf("%s", newName);
		detail.type = inputDetailClass();
		if (notEmpty) { 
		    db.lock();
		    if (cursor.select(q1) > 0) { 
			detail.assembly = cursor.currentId();
		    } else { 
			printf("No such detail\n");
			break;
		    }
		} else { 
		    detail.assembly = null;
		} 
		insert(detail);
		notEmpty = true;
		break;
	      case 2:
		printf("Enter assembly name: ");
		scanf("%s", name);
		type = inputDetailClass();
		if (cursor.select(q1) != 0) { 
		    parts = cursor->parts;
		    if (cursor.select(q2)) { 
			do { 
			    cursor->print();
			} while (cursor.next());
		    } else { 
			printf("This detail doesn't contain subparts\n");
		    }
		} else { 
		    printf("No such detail\n");
		}
		break;
	      case 3:
		if (cursor.select("start from first follow by parts")) { 
		    do { 
			cursor->print();
		    } while (cursor.next());
		} else { 
		    printf("No details\n");
		}
		break;
	      case 4:
		printf("Enter assembly name: ");
		scanf("%s", name);
		if (cursor.select(q1) != 0) { 
		    parts = cursor->parts;
		    if (cursor.select(q3)) { 
			do { 
			    cursor->print();
			} while (cursor.next());
		    } else { 
			printf("This detail doesn't contain subparts\n");
		    }
		} else { 
		    printf("No such detail\n");
		}
		break;
	      case 5:
		printf("Enter detail name: ");
		scanf("%s", name);
		if (cursor.select(q1) != 0) { 
		    assembly = cursor->assembly;
		    if (cursor.select(q4)) { 
			do { 
			    printf("assembly %s\n", cursor->name);
			} while (cursor.next());
		    } else { 
			printf("This detail is not part of any assembly\n");
		    }
		} else { 
		    printf("No such detail\n");
		}
		break;
	      case 6:
		db.close();
		return EXIT_SUCCESS;
	    }
	    db.commit();
	}
    } else { 
	fprintf(stderr, "Failed to open database\n");
	return EXIT_FAILURE;
    }
}