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FMDB基本使用和SQL语句其中的坑

FMDB基本使用和SQL语句其中的坑

作者: CoCc | 来源:发表于2017-08-01 11:11 被阅读0次

    最近公司项目做完了,没事干。就自己把数据库加进去了。用的是FMDB,而且有二次简陋封装。

    FMDB的基本使用已经有么很多文章,我这里主要是介绍一些坑。

    • 建表
    _instance.dbQueue = [FMDatabaseQueue databaseQueueWithPath:SQLFilePath];
        
    [_instance.dbQueue inDatabase:^(FMDatabase *db) {
            
         if ([db executeStatements:@"CREATE TABLE IF NOT EXISTS USERDATA(number integer primary key not NULL, user_name text, net_asset text, earned_amount text, usable_amount text, open_newnet integer, to_callback_principal text, to_callback_earned text, open_fingerMark integer, gesture_code text)"]) {
              XZLog(@"create success");
          } else {
              XZLog(@"create failed");
         }
    }];
    

    FMDB不支持BOOL类型,所以如果要存的话还是integer类型。

    • 根据某个值再数据库查找
    - (BOOL)hasDataFromKey:(NSString *)key
    {
        __block BOOL flag = NO;
        [_instance.dbQueue inDatabase:^(FMDatabase *db) {
            
            FMResultSet *set = [db executeQueryWithFormat:@"SELECT user_name FROM USERDATA WHERE user_name = %@", key];
            if ([set next]) {
                flag = YES;
            }
            [set close];
        }];
        
        return flag;
    }
    

    这里我有一个疑问,写完这个去测试的时候提示我应该去调用[set close]。如果我使用while的话则不需要。

    • 插入新数据
    - (void)insertData:(XZUserInfomationData *)data;
    {
        [_instance.dbQueue inDatabase:^(FMDatabase *db) {
            NSString *sql = @"INSERT INTO USERDATA (user_name, net_asset, earned_amount, usable_amount, open_newnet, to_callback_principal, to_callback_earned, open_fingerMark, gesture_code) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";
            if ([db executeUpdate:sql, data.user_name, data.net_asset, data.earned_amount, data.usable_amount, [NSNumber numberWithBool:data.open_newnet], data.to_callback_principal, data.to_callback_earned, [NSNumber numberWithBool:data.open_fingerMark], data.gesture_code]) {
                XZLog(@"insert success");
            } else {
                XZLog(@"insert failed");
            }
        }];
    }
    

    就这里是巨大的坑,当你用字符串去保存数字时,如果数字开头是0的时候,保存到数据库的话会把0去掉。这是我往数据库存手势密码发现的。例如手势密码是03678,存到数据库就成了3678。解决办法在下面更新数据的方法里。同时存bool类型需要转成NSNumber类型。

    • 更新数据
    - (void)updateData:(XZUserInfomationData *)data
    {
        if (!data.gesture_code.length) { // 这个是为了判断可以忽略
           data.gesture_code = @"0";
        }
        
        [_instance.dbQueue inDatabase:^(FMDatabase *db) {
            
            NSString *sql = [NSString stringWithFormat:@"UPDATE USERDATA SET net_asset = %@, earned_amount = %@, open_newnet = %d, usable_amount = %@, to_callback_principal = %@, to_callback_earned = %@, open_fingerMark = %d, gesture_code = '%@' WHERE user_name = '%@'", data.net_asset, data.earned_amount, data.open_newnet, data.usable_amount, data.to_callback_principal, data.to_callback_earned, data.open_fingerMark, data.gesture_code, data.user_name];
            if ([db executeUpdate:sql]) {
                XZLog(@"update success");
            } else {
                XZLog(@"update failed");
            }
        }];
    }
    

    更新gesture_code = '%@'加单引号表明这个是一个字符串而不是一串数字,SQL会自己判断如果不加则会被认为是数字就自动把开头0去掉。

    • 根据指定key得到数据库的值
    - (XZUserInfomationData *)dataFromKey:(NSString *)key
    {
        XZUserInfomationData *data = [XZUserInfomationData sharedInstanceData];
        
        [_instance.dbQueue inDatabase:^(FMDatabase *db) {
            
            FMResultSet *set = [db executeQueryWithFormat:@"SELECT * FROM USERDATA WHERE user_name = %@", key];
            
            while ([set next]) {
                
                data.user_name = [set stringForColumn:@"user_name"];
                data.net_asset = [set stringForColumn:@"net_asset"];
                data.earned_amount = [set stringForColumn:@"earned_amount"];
                data.open_newnet = [set boolForColumn:@"open_newnet"];
                data.usable_amount = [set stringForColumn:@"usable_amount"];
                data.to_callback_principal = [set stringForColumn:@"to_callback_principal"];
                data.to_callback_earned = [set stringForColumn:@"to_callback_earned"];
                data.open_fingerMark = [set boolForColumn:@"open_fingerMark"];
                data.gesture_code = [set stringForColumn:@"gesture_code"];
            }
        }];
        
        return data;
    }
    

    以上就是基本的增删改查,下面有时间我还会把数据库迁移补上。

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