newobj.c

eXtremeDB数据库在Linux平台下的使用源码。内含多个示例程序

/*****************************************************************
 *                                                               *
 * Copyright (c) 2001-2007 McObject LLC. All Right Reserved.     *
 *                                                               *
 *****************************************************************/
#include "platform.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "samples.h"

/* This function writes a new object of SimpleClass
 * into the database.
 */
int newobj( mco_db_h db, int id0, uint4 vh ) {
	MCO_RET             rc;
	mco_trans_h         t;

	/*
	 * SimpleClass and simple_id typedefs are generated by the DDL compiler and
	 * could be found in simple.h
	 */
	SimpleClass hClass;
	simple_oid  id;
	char                src[64];
	int                 donetrn = 0;
	uint2               va = ( uint2 ) ( rand() & 0x3FF );
	uint2               vb = ( uint2 ) ( rand() & 0x3FFF );

	sprintf( src, "abc_%d", id0 );

	id.seq = id0;

	/*
	 * open a transaction and obtain a transaction handle. This transaction is a
	 * read_write transaction, ran at the FOREGROUND priority level.
	 */
	mco_trans_start( db, MCO_READ_WRITE, MCO_TRANS_FOREGROUND, &t );

	/*
	 * Allocate a new class and return a class handle. Two input parameters must be
	 * passed to the new interface: the transaction handle t and class id. If
	 * successful the output parameter hClass is a pointer to the newly allocated class.
	 */
	rc = SimpleClass_new( t, &id, &hClass );
	if ( rc ) goto Err;

	/* assign values, two integers and a string. By this time, we must
	 * know the string size already. Note that return value is not checked
	 * with every call. In case of an error, runtime sets the transaction into
	 * set "error state" and will return the error indication at commit
	 */
	SimpleClass_a_put( &hClass, va );
	SimpleClass_b_put( &hClass, vb );
	SimpleClass_c_put( &hClass, src, (uint2) strlen(src) );
	SimpleClass_h_put( &hClass, vh );

	/* 
	 * commit the transaction unless there is a problem and return 1, otherwise
	 * rollback and return 0
	 */
	rc = mco_trans_commit( t );
	donetrn = 1;

	/*
	 * Important! After the transaction was committed, the class handle is no longer
	 * valid. Any attempt to reference the created object would result in error
	 * condition.
	 */
	if ( rc ) goto Err;

	printf( "\n\tobject with OID=%d, a=%d, b=%d, c=%s\tinserted okay", id.seq, va, vb, src );
	return 1;

	Err:
	printf( "\n\terror (%d) inserting object with OID %d", rc, id.seq );

	if ( !donetrn ) mco_trans_rollback( t );
	return 0;
}