Qt判断数据库是否已存在某表以及判断某表是否存在某列

QSqlQuery query(db);

 QString selectsql;

selectsql ="select * from sys.tables where name='car_bayonet_info'" ;//是否已经存在表car_bayonet_info
   query.exec(selectsql);
    if(!query.next())
    {
        SQLError = GBK("表car_bayonet_info不存在或不完整");
        return false;
    }
    selectsql ="select * from syscolumns where id=object_id('car_bayonet_info') and name='Cross_ID'";//表car_bayonet_info是否已经存在Cross_ID字段
    query.exec(selectsql);
    if(!query.next())
    {
        SQLError = GBK("表car_bayonet_info不存在或不完整");
        return false;
    }
    selectsql ="select * from syscolumns where id=object_id('car_bayonet_info') and name='bay_name'";
    query.exec(selectsql);
    if(!query.next())
    {
        SQLError = GBK("表car_bayonet_info不存在或不完整");
        return false;
    }