db.c

extremeDB s sample code,useful for you

/***************************************************************
 *                                                             *
 * Copyright (c) 2001-2006 McObject LLC. All Right Reserved.   *
 *                                                             *
 ***************************************************************/

/* 
 * This sample shows how to use mco_db_save() and mco_db_load() APIs. These APIs are
 * used to save and load in-memory database to and from any stream device, such as
 * a file or socket.
 * The application presented here was used as actual test to verify the "correctness"
 * of the save and load operations. The schema file dbtest.mco describes declares classes
 * with various data types and various layouts.
 *
 * The project consists of several C files:
 *
 * dbinit.c - functions to initialize the database with the test data.
 * db.c - main driver.
 * dbtest.c - generated interface implemetation file
 * strm.c - FILE stream implemetaion
 * verify.c - functions that read the database back after it has been loaded with mco_db_load
 *            and validates the results.
 */

#include "platform.h"
#include "load.h"

const int MAP_ADDRESS =  0x20000000;

static void _SH_(void) {

	char text[] = {
		"\nThis sample shows how to use mco_db_save() and mco_db_load() APIs.\n"
		"These APIs are used to save and load in-memory database to and from\n"
		"any stream device, such as a file or a socket.\n"
		"The application presented here was used as an actual test to verify the\n"
		"\"correctness\" of the save and load operations. It populates a database\n"
		"that contains classes with the \"fixed\", and \"dynamaic\" fields, a class\n"
		"with blobs, a class with declared with \"autoid\" and \"histoty\", etc.\n"
		"The applicataion then saves the database to the file, closes the connection,\n"
		"re-opens the database and loads the saved image into the memory. It then\n"
		"performs sanity check on the loaded data and prints out the results\n"
	};

	char text1[] = {
		"Copyright (c) 2001-2006 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();
}


static void errhandler( int n ) {
	printf( "\neXtremeDB runtime fatal error: %d", n );
	getchar();
	exit( -1 );
}


mco_runtime_info_t info;

int main( void ) {
	MCO_RET     rc;
	mco_db_h    db = 0;
	FILE * f;

	void *start_mem;

	_SH_();

	mco_get_runtime_info( &info);
	if (!info.mco_save_load_supported) {
		printf("This sample requires SAVE/LOAD runtime support\n");
		exit(0);
	}

	if ( info.mco_shm_supported ) {
		start_mem = (char*)MAP_ADDRESS;
	}
	else {
		start_mem = (char*)malloc(DBSIZE);
		if (!start_mem) {
			printf("Couldn't allocated memory\n");
			exit (1);
		}
	};

	mco_error_set_handler( &errhandler );

	mco_runtime_start();
	/* Create a database - allocate 2M starting from mem. */
	rc = mco_db_open( "dbtest", dbtest_get_dictionary(), start_mem, DBSIZE, (uint2) PAGESIZE );

	if ( rc ) {
		printf( "\nerror creating database" );
		if ( !info.mco_shm_supported )
			free( start_mem );
		exit( 1 );
	}

	/* connect to the database, obtain a database handle */
	mco_db_connect( "dbtest", &db );

	printf ("Initializing database...");
	rc = init_database(db);
	if (rc) {
		printf("\tfailed, rc=%d\n\n", rc);
                mco_db_disconnect(db);  
		goto end;
	}

	printf ("\tsuccess\n");
	printf ("Saving database to %s...",fname);

	f = fopen(fname,"wb");
	rc = mco_db_save(f, file_writer, db);

	if(rc) {
		fclose(f);
		printf("\tfailed, %d\n", rc);
		goto end;
	}

	printf ("\tsuccess\n\n");
	fclose(f);

	/* disconnect from the database, db is no longer valid */
	mco_db_disconnect( db );
	mco_db_close( "dbtest" );

	printf ("Loading data from %s...",fname);


 
        f = fopen(fname,"rb");
	rc = mco_db_load(f,file_reader,"dbtest", dbtest_get_dictionary(),
		start_mem,DBSIZE);

	fclose(f);

	if(rc) {
		printf("\tfailed, rc=%d\n\n", rc);
		goto end;
	} else
		printf("\tsuccess\n");

	mco_db_connect("dbtest", &db);

	printf ("Verifying data pointers ...");
	rc= verify_db(db);
	if (rc)
		printf("\tfailed\n\n");
	else
		printf ("\tsuccess\n\n");

	printf ("Verifying object counters...\n\n");
	printf ("\tWritten\t%d objects to class \"Dynamic\"\n", nd);
	printf ("\tWritten\t%d objects to class \"Fixed\"\n", nf);
	printf ("\tWritten\t%d objects to class \"Blobs\"\n", nb);
	printf ("\tWritten\t%d versions for class \"Blobs\"\n", nh);

	printf ("\tWritten\t%d vector elements to class \"Idxs\"\n\n", ni);
	printf ("\tRead\t%d objects from class \"Dynamic\"\n", dv);
	printf ("\tRead\t%d objects from class \"Fixed\"\n", fv);
	printf ("\tRead\t%d objects from class \"Blobs\"\n", bv);
	printf ("\tRead\t%d version from class \"Blobs\"\n", bh);
	printf ("\tRead\t%d vector elements from class \"Idxs\"\n\n", iv);

	mco_db_disconnect( db );

end:
	mco_db_close( "dbtest" );
	mco_runtime_stop();

	if ( !info.mco_shm_supported )
		free( start_mem );

	printf( "Press Enter to finish\n" );
	getchar();
  PROG_EXIT(0);
}