トランザクション処理

• 標準APIを使ったサンプル
• コンビニエンスAPIを使ったサンプル

標準APIを使ったサンプル

#include <stdio.h>
#include <bzs/db/protocol/tdap/client/database.h>
#include <bzs/db/protocol/tdap/client/table.h>
#include <bzs/db/protocol/tdap/client/dbDef.h>

using namespace bzs::db::protocol::tdap::client;
using namespace bzs::db::protocol::tdap;

/**
@brief update records in transaction example

This program updates some records of a "user" table.
Change group of user in group 1 to 3

Please execute "create database" , "change schema" and "insert records" example
        before execute this example.

*/

static const short fieldnum_id = 0;
static const short fieldnum_name = 1;
static const short fieldnum_group = 2;
static const short fieldnum_tel = 3;

static const char_td keynum_group = 1;
/** show database operation error
*/
void showError(const _TCHAR* caption, const _TCHAR* tableName, short statusCode)
{
    _TCHAR tmp[1024] = { 0x00 };
    nstable::tdapErr(0x00, statusCode, tableName, tmp);
    _tprintf(_T("[ERROR] %s No.%ld %s\n"), caption, statusCode, tmp);
}

bool updateUsers(table* tb)
{
    tb->clearBuffer();
    tb->setKeyNum(keynum_group); // use group key
    tb->setFV(fieldnum_group, 1); // set group = 1;
    tb->seekGreater(true /*orEqual*/);
    while (tb->stat() == 0)
    {
        // check group value.
        if (tb->getFVint(fieldnum_group) != 1)
            break;

        // update group
        tb->setFV(fieldnum_group, 3); // change group 1 to 3
        tb->update(
            nstable::changeCurrentNcc /*ncc=true*/); // Important ncc=true !
        if (tb->stat() != 0)
            showError(_T("update user"), tb->tableDef()->tableName(),
                      tb->stat());
        else
            tb->seekNext();
    }
    return ((tb->stat() == STATUS_EOF) || (tb->stat() == 0));
}

/** Open database
 */
bool openDatabase(database* db, const _TCHAR* uri)
{
    /******************************************************
     !!!  Important   !!!
     When using a multi-threaded, 
     please request a new connection for each database. 
    *******************************************************/
    // When using a multi-threaded, set to true.
    bool newConnection = false; 
    if (!db->connect(uri, newConnection))
    {
        showError(_T("connect daatabase"), NULL, db->stat());
        return false;
    }
    
    db->open(uri, TYPE_SCHEMA_BDF);
    if (db->stat() != 0)
    {
        showError(_T("open daatabase"), NULL, db->stat());
        return false;
    }
    return true;
}

#pragma argsused
int _tmain(int argc, _TCHAR* argv[])
{
    int result = 0;
    static const _TCHAR* uri = _T("tdap://localhost/test?dbfile=test.bdf");
    database* db = database::create();

    if (openDatabase(db, uri))
    {
        table* tbu = db->openTable(_T("user"));
        if (db->stat() != 0)
            showError(_T("open user table"), NULL, db->stat());
        else
        {
            db->beginTrn();
            if (updateUsers(tbu))
            {
                db->endTrn();
                _tprintf(_T("Update records success. \n"));
            }
            else
                db->abortTrn();
            tbu->release();
        }
        db->close();
    }
    database::destroy(db);
    return result;
}

コンビニエンスAPIを使ったサンプル

#include <bzs/db/protocol/tdap/client/trdboostapi.h>
#include <iostream>

using namespace bzs::db::protocol::tdap::client;
using namespace bzs::db::protocol::tdap;

/**
@brief update records in transaction example

This program updates some records of a "user" table.
Change group of user in group 1 to 3

Please execute "create database" , "change schema" and "insert records" example
        before execute this example.

*/

static const short fieldnum_id = 0;
static const short fieldnum_group = 2;
static const char_td keynum_group = 1;

int isGroupOne(const fields& fds)
{
    return (fds[fieldnum_group].i() == 1) ? filter_validate_value
                                          : filter_invalidate_value;
}

void changeGroup1To3(const fields& fds)
{
    fds[fieldnum_group] = 3;
    updateRecord(fds);
}

void updateUsers(table_ptr tb)
{
    // Execute seekGreaterOrEqual with key number and key value
    indexIterator it = readIndex_v(tb, eSeekGreaterOrEqual, keynum_group, 1);

    // Wrap filtered iterator
    filterdIndexIterator itf(it, isGroupOne);

    // loop each group=1 records and update
    for_each(itf, changeGroup1To3);
}

#pragma argsused
int _tmain(int argc, _TCHAR* argv[])
{
    database_ptr db = createDatabaseObject();
    try
    {
        connectParams param(_T("tdap"), _T("localhost"), _T("test"),
                            _T("test"));
        /******************************************************
         !!!  Important   !!!
         When using a multi-threaded, 
         please request a new connection for each database. 
        *******************************************************/
        // When using a multi-threaded, set to true.
        bool newConnection = false;          
        connectOpen(db, param, newConnection);

        table_ptr tb = openTable(db, _T("user"));
        dbTransaction trn(db);

        // start transaction
        trn.begin();

        updateUsers(tb);

        // Commit transaction. If an error throwed then abort transaction
        // automaticaly.
        trn.end();

        std::cout << "Update records success." << std::endl;
        return 0;
    }

    catch (bzs::rtl::exception& e)
    {
        std::tcout << _T("[ERROR] ") << *bzs::rtl::getMsg(e) << std::endl;
    }
    return 1;
}