newobj.c

PB 熟悉的哥们希望大家可以互相学习一下

/*****************************************************************
 *                                                               *
 * 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;
}