Question

我在我的代码中集成了FMDB库，我尝试在单个函数中加载多个查询但我收到了一些问题

* Error calling sqlite3_step (21: out of memory) rs 
* FMDB not open
* FMDB is in use

是否可以在单一功能中运行多个查询？，请让我知道您的意见。

先谢谢

我试过这个FYI：

-(NSMutableArray *)getMyInfo
{
   NSMutableArray *contactList = [NSMutableArray array];

    if(![instance.database open])
    {
        DLog(@"Could not open DB");
        return nil;
    }
    **********  QUERY 1   **************
    FMResultSet *resultSet=[instance.database executeQuery:@"SELECT * FROM mycontacts WHERE cont_hidden = 0 and cont_recent_chat_time IS NOT NULL ORDER BY strftime(cont_recent_chat_time) DESC"];
    if(resultSet)
    {
        while([resultSet next])
        {
            @autoreleasepool
            {
                int type = [resultSet intForColumn:@"contact_type"];
                Contactbean *contactObj = [[Contactbean alloc]init];
                [contactObj setPhoneNo:[resultSet stringForColumn:@"cont_phonenumber"]];

********** QUERY 2 **************

                FMResultSet *getCountResult=[instance.database executeQuery:@"SELECT count(kchatid) FROM mychat WHERE kisread = 0 and kchatnumber = ?",[resultSet stringForColumn:@"cont_phonenumber"]];
                if ([getCountResult next]) {
                    if([getCountResult intForColumnIndex:0] > 0)
                    {
                        [contactObj setCount:[getCountResult intForColumnIndex:0]];
                    }
                }
                [getCountResult close];

********** QUERY 3 **************

                FMResultSet *getRecentResult=[instance.database executeQuery:@"SELECT * from mychat where kchatnumber =? AND kchattime =?",[resultSet stringForColumn:@"cont_phonenumber"],[resultSet stringForColumn:@"status"]];

                if([getRecentResult next])
                {
                    [contactObj setStatus:[getRecentResult intForColumn:@"status"]];
                }
                [getRecentResult close];

                // Adding contact to the list
                [contactList addObject:contactObj];
            }
        }
    }
    [resultSet close];
    [instance.database close];
    return contactList;
}

Answer 1

你没有正确地打开和关闭数据库对象，应该是这样的：

NSArray *docPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = [docPaths objectAtIndex:0];
    NSString *dbPath = [documentsDir stringByAppendingPathComponent:@"theDataBase.sqlite"];
    FMDatabase *database = [FMDatabase databaseWithPath:dbPath];
    [database open];//Open the database
    //Execute the update you want
    [database executeUpdate:@"INSERT INTO some_table (something) values (?)", someValue];
    //Execute the consults you want
    FMResultSet *results   = [database executeQuery:@"SELECT * FROM some_table"];
        if ([results next])
        {
            //Do something with the data it brings you
        }
    [database close];//Close the database

别忘了阅读官方文档： FMDB v2.5

FMDB - 调用sqlite3_step（21：内存不足）rs时出错

1 个答案: