McoSqlOpenParameters类

示例 api_sql_02_open_initililize 展示了如何使用默认的打开参数以及简单地调用 engine.open() 来管理内存数据库。若要管理持久化或混合数据库（包含持久化和临时类），或者管理具有多个内存段的数据库，则需要额外的步骤来定义内存设备以及运行时缓存和日志参数。这可以通过设置 McoSqlOpenParameters 并将其传递给 McoSqlEngine.Open() 方法来实现。

    int main()
    {
        McoSqlOpenParameters params;
 
        // 设置 MCO SQL 参数
        params.databaseName = "persondb";
        params.dictionary = persondb_get_dictionary();
        params.mainMemoryDatabaseSize = MEMORY_DATABASE_SIZE;
        params.mainMemoryPageSize = PAGE_SIZE;
        params.diskDatabaseFile = "persondb.dbs";
        params.diskDatabaseLogFile = "persondb.log";
        params.diskCacheSize = DISK_CACHE_SIZE;
        params.logType = REDO_LOG;
        engine.open(params);
         
        // 数据库处理代码
        
        engine.close();
     
        return 0;
    }

可以通过调用 setDefaultValues() 方法来设置 McoSqlOpenParameters 的默认值，具体如下：

    void McoSqlOpenParameters::setDefaultValues()
    {
        databaseName = NULL;
        dictionary = NULL;
        mainMemoryDatabaseSize = 0;
        mainMemoryDatabaseAddress = MCO_DATABASE_DEFAULT_MAP_ADDRESS;
        maxTransactionSize = 0;
        maxConnections = 100;
        mainMemoryPageSize = 128;
        hashLoadFactor = 100;
        flags = DEFAULT_OPEN_FLAGS;
        modeMask = 0;
        savedImage = NULL;
        diskDatabaseFile = NULL;
        diskDatabaseLogFile = NULL;
        diskDatabaseMaxSize = MCO_INFINITE_DATABASE_SIZE;
        diskCacheMemoryAddress = 0;
        diskCacheSize = 0;
        diskPageSize = 4096;
        streamReader = NULL;
        stream = NULL;
        remoteEngine = NULL;
        redoLogLimit = MCO_DEFAULT_REDO_LOG_LIMIT;
        logType = REDO_LOG;
        defaultCommitPolicy = MCO_COMMIT_SYNC_FLUSH;
        transSchedPolicy = MCO_SCHED_FIFO;
        devices = NULL;
        n_devices = 0;
        tables = NULL;
        n_tables = 0;
        maxClasses = 0;
        maxIndexes = 0;
        maxDictionarySize = 0;
        dictionaryFlags = 0;
        maxTransTime = 0;
        maxActivePages = 32;
    }