In MySQL, what is the difference between storing data in multiple columns vs storing data in JSON columns

Let's say I have a table called T1. Initially, it has ID, Identifier, C1, C2 as columns. Over time I will add new columns C3, C4 and so on. Would it be better to have these columns as ID, Identifier, Info? Where Info is a JSON column containing C1, C2, C3 as keys and their corresponding values. What...

P粉393030917 2023-07-24 16:17:05 0  1  286

:: question

syntax error, unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM), expecting identifier (T_STRING)

s. y.30h.c. t .m.g.w. 2019-04-16 15:04:47 0  0  659

phpstudy reports an error when configuring a virtual host. What is the problem?

thinkphp was created through composer, version 5.1.0. I used phpstudy to configure the virtual host in Windows and got an error when opening public. I don’t know the reason. Can someone check it out? Parse error: syntax error, unexpected 'class' (T_CLASS), expecting identifier (T_STRING) or variable...

liuwaiwai 2018-12-10 21:19:20 0  0  697

Error when running laravel

I just changed an integrated tool. I just configured the domain name and accessed it. Then I got an error index.php:Parse error: syntax error, unexpected 'class' (T_CLASS), expecting identifier (T_STRING) or variable (T_VARIABLE) or '{' or '$' in E:\

奔跑者 2018-10-13 16:59:18 0  0  1089

Thinkphp 5.1 error after installation

报错的内容如下：Parse error: syntax error, unexpected 'class' (T_CLASS), expecting identifier (T_STRING) or variable (T_VARIABLE) or '{' or '$' in E:\myphp\PHPTutorial\WWW\web\thi

嘿嘿 2018-06-12 18:08:51 0  3  1336

Access error

Parse error: syntax error, unexpected 'class' (T_CLASS), expecting identifier (T_STRING) or variable (T_VARIABLE) or '{' or '$' in C:\PHPStudy\WWW\tp5\thinkphp\base.php&nb

hello sun 2018-05-06 15:19:28 0  0  893

Array object Unexpected identifier - Stack Overflow

The problem is as shown in the picture. I don’t understand why the program displays undefined? The console reports an error?

给我你的怀抱 2017-07-05 10:56:12 0  1  703

ios - Personal developer account, writing demo, when naming Bundle Identifier, it shows that the certificate cannot be automatically configured.

Cannot create a iOS App Development provisioning profile

ringa_lee 2017-05-16 13:18:10 0  1  852

angular.js - Ionic 2 构建过程中报错 Duplicate identifier 'Promise'

搜索了一下貌似和问题匹配比较好的地方都没有给出解决方法。。。 求助 _(:3

phpcn_u1582 2017-05-15 17:08:00 0  2  409

objective-c - oc获取DocumentDirectory目录报错expected identifier

获取DocumentDirectory目录报错为什么会报错expected identifier

ringa_lee 2017-05-02 09:20:19 0  2  468

objective-c - Xcode这个报错怎么办？

(null): error: Embedded binary's bundle identifier is not prefixed with the parent app's bundle identifier.

ringa_lee 2017-04-28 09:04:15 0  1  427

mongodb 命令行插入date类型报错

如何在命令行插入当前时间的数据 {代码...} 报错：2015-05-13T11:48:48.210+0800 SyntaxError: Unexpected identifier {代码...} 报错：2015-05-13T11:52:40.841+0800 SyntaxError: Unexpected identifier 急急急...

伊谢尔伦 2017-04-25 09:02:49 0  1  534

MongoDB怎样批量执行命令？

目前已经找到一种方法，但是该方法存在问题，即无法有效处理文档过长的情况。 {代码...} 当insert的文档过长时，该方法会报错，显示unexpected token ILLEGAL和unexpected identifier。但是在Robomongo中执行同样...

天蓬老师 2017-04-24 09:10:43 0  2  468

java - zookeeper集群报错

zookeeper集群其中一个节点报错：【Have smaller server identifier, so dropping the connection: (2, 1)】原始配置：zoo.cfg: clientPort=2181dataDir=/server/zookeeperdataLogDir=/server/zookeepersyncLimit...

高洛峰 2017-04-18 10:06:40 0  0  212

ios - react native 里项目的名字怎么改？

如上图，用xcode打开我的react－native 的项目后是这样的，这个项目是在react-navigation 官方的例子的基础上开发， 该怎么改成我自己的名字，bundle identifier 可以自己改吗，改了会不会影响现在的真机调试？不...

PHPz 2017-04-18 09:57:55 0  1  457

objective-c - iOS UITest问题,OC下XCTAssertEqual错误

OC下使用XCTAssertEqual进行断言,判断当前导航栏的标题是否是期望值. {代码...} 可以看到 打印输出的identifier确实是Mune,但是断言不通过?XCTAssertEqual是通过地址来进行匹配的么? 自己试着通过搜索解决问题,但...

伊谢尔伦 2017-04-18 09:50:48 0  1  402

ios - 免费真机调试的问题

用xcode automatically manage signing 我用的是原来用的bundid，现在显示 The app ID "xxxxxxxxxxxxx" cannot be registered to your development team. Change your bundle identifier to a unique string to t...

巴扎黑 2017-04-18 09:46:53 0  2  264

ios - framework的bundle identifier的作用

Xcode里面如果target是framework，会有bundle identifier，请问有何用？.a库都没有这个id的啊！

巴扎黑 2017-04-18 09:45:02 0  2  396

IOS SEGV_ACCERR 异常

bugly定位IOS SEGV_ACCERR 异常, 各位大神帮忙看下代码哪里有问题 {代码...} crash 上报这一行出问题: int index = ABMultiValueGetIdentifierAtIndex(phone, identifier); 下边是错误堆栈 {代码...}

高洛峰 2017-04-18 09:34:04 0  1  285

ios - CollectionView.xib中创建多个nibCell,用的时候如何使用？？

如图：我在collection.xib中创建了2个cell,定义了不同的identifier, 使用的时候： {代码...} {代码...} 这样能运行，但是取出的cell都是上面什么也没有。是我注册cell不对吗？？还是因为不能这样用？tableViewCel...

天蓬老师 2017-04-18 09:29:28 0  6  650