?? delete.c
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/***************************************************************
* *
* Copyright (c) 2001-2007 McObject LLC. All Right Reserved. *
* *
***************************************************************/
/*
* This example demonstrates hash-based serach functionality,
* erase/delete interfaces and database statistics methods.
*/
#include <platform.h>
#include <stdio.h>
#include <stdlib.h>
#include "samples.h"
static const char* dbname = "SimpleDb";
static const int FIRST_SEGSZ = 1024 * 8000UL;
#ifndef MCO_PLATFORM_X64
static const int PAGESIZE = 96;
#else
static const int PAGESIZE = 192;
#endif
const int MAP_ADDRESS = 0x20000000;
void _SH_(void)
{
char text[] =
{
"\nThis example demonstrates eXtremeDB hash-based search interfaces,\n"
"erase and delete interfaces and database statistics methods.\n"
};
char text1[] =
{
"Copyright (c) 2001-2007 McObject LLC. All Right Reserved.\n\n"
};
printf("%s\neXtremeDB runtime version %d.%d, build %d\n%s\n\nPress Enter to start", text, MCO_COMP_VER_MAJOR,
MCO_COMP_VER_MINOR, MCO_COMP_BUILD_NUM, text1);
getchar();
}
/* Display database statistics
*/
void showStat(mco_db_h db, uint2 class_code)
{
MCO_RET rc = 0;
mco_trans_h t;
mco_class_stat_t stat;
mco_trans_start(db, MCO_READ_WRITE, MCO_TRANS_FOREGROUND, &t);
rc = mco_class_stat_get(t, class_code, &stat);
mco_trans_commit(t);
if (rc == MCO_S_OK)
{
printf(
"\n\tStatistics for the class with code %d:\n\tNumber of objects:\t%ld\n\tTotal pages used:\t%ld\n\tTotal core used:\t%ld\n", class_code, stat.objects_num, stat.core_pages + stat.blob_pages, stat.core_space);
}
}
/* Find and object based on hash index created for the class. Ones found
* delete the object and return all memory back to the pool.
*/
int find_and_delete(mco_db_h db, uint4 vh)
{
MCO_RET rc;
mco_trans_h t;
SimpleClass hClass;
simple_oid id;
mco_trans_start(db, MCO_READ_WRITE, MCO_TRANS_FOREGROUND, &t);
rc = SimpleClass_SimpleKey_find(t, vh, &hClass);
if (rc == MCO_S_OK)
{
/* delete it!*/
rc = SimpleClass_oid_get(&hClass, &id);
printf("\n\tobject with OID=%d about to be deleted...", id.seq);
rc = SimpleClass_delete(&hClass);
if (rc == MCO_S_OK)
{
printf("okay\n");
mco_trans_commit(t);
}
else
{
printf("failed (%d)\n", rc);
mco_trans_rollback(t);
}
}
else
{
printf("\n\terror(%d) searching for the object with hash value %d", rc, vh);
mco_trans_rollback(t);
}
return (int)rc;
}
int main(void)
{
MCO_RET rc;
mco_db_h db = 0;
int num = NUMOBJECTS, one_id[NUMOBJECTS], vhash[NUMOBJECTS];
char* start_mem;
mco_runtime_info_t info;
_SH_();
mco_get_runtime_info(&info);
if (info.mco_shm_supported)
{
start_mem = (char*)MAP_ADDRESS;
}
else
{
start_mem = (char*)malloc(FIRST_SEGSZ);
if (!start_mem)
{
printf("Couldn't allocated memory\n");
exit(1);
}
};
mco_runtime_start();
rc = mco_db_open(dbname, simple_get_dictionary(), start_mem, FIRST_SEGSZ, (uint2)PAGESIZE);
if (rc)
{
printf("\nerror %d creating database", rc);
if (!info.mco_shm_supported)
{
free(start_mem);
}
exit(1);
}
/* connect to the database, obtain a database handle */
mco_db_connect(dbname, &db);
printf("\ndb handle = %d\n", db);
srand((unsigned)time(NULL));
while (0 < num--)
{
/* get some random values */
one_id[num] = rand();
vhash[num] = (uint4)rand();
/* create a new object */
newobj(db, one_id[num], vhash[num]);
}
printf("\n");
/* print out statistics for SimpleClass */
showStat(db, SimpleClass_code);
printf("\n\nHash-based search & delete\n");
for (num = NUMOBJECTS; 0 < num; num--)
{
find_and_delete(db, vhash[num - 1]);
}
showStat(db, SimpleClass_code);
/* disconnect from the database, db is no longer valid */
mco_db_disconnect(db);
/* destroy the db */
mco_db_close(dbname);
mco_runtime_stop();
if (!info.mco_shm_supported)
{
free(start_mem);
}
printf("Press Enter to finish\n");
getchar();
PROG_EXIT(0);
}
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