vs2019连接MySQL You have a usable connection already.

2020-11-04

WCF IIS配置并引用并初步使用Mysql数据库

学习网址：https://docs.microsoft.com/zh-cn/dotnet/framework/wcf/how-to-create-a-wcf-client本地资源配置与IIS资源配置我是根据微软官网学习的，有兴趣的可以跟着敲一下，我这里只说一下我遇到的问题 IIS 再IIS中配置服务时，根据教程上创建虚拟目录，发现如果我如果再默认站点创建服务将会提示InvalidOperationException: 找不到类型“Microsoft.ServiceModel.Samples.CalculatorService,发现我再默认站点已经托管了一个服务导致的问题。应该是今天感冒有点迟钝新建站点：1.1. 将我们的路径端口及名称输入即可，和创建Web站点一个步骤。创建文件APP_Code、service.svc、Web.config,其中Web.config文件按照官方给的案例后面将会出现无法打开安全通道，因为与远程终结点的安全协商已失败。这可能是由于用于创建通道的 EndpointAddress 中不存在 EndpointIdentity 或错误指定了 Endpoint...

2020-04-17

MySQL String Error in insert into Statement

When passing values, looking at C# code directly passing string value, error reported showing matching column not found 1command += "INSERT INTO " + TableName + "(data_id,data_desc,data_price) VALUES(" + ids[i] + ", " + description[i] + "," + price[i] + ");"+"\r\n"; After the running error, I found that I didn’t consider that the command is passed completely in string form. At this time, the string passed by description does not have...

2021-01-22

MySQL Lock Granularity and ACID

Table Lock: It locks the entire table. Before a user performs a write operation (insert, delete, update, etc.) on the table, they need to acquire a write lock first, which will block all read and write operations on the table by other users. When there is no write lock, other users can obtain read locks, and read locks between multiple users do not block each other.Row Lock: Row-level locks can support concurrent processing to the greatest extent (and also bring the largest lock overhead). AC...

2021-01-06

Mysql Function to Query All Child Nodes Based on Parent Node

The data volume is 5k+. Referring to the function given in the blog, it takes 15s to run once, which is too long. So finally I didn’t choose to traverse data in Mysql, but traversed in the class when the user selects the parent node. The overall time consumption will be much smaller, and it will not bring lag feeling to the user. I don’t use Mysql functions much usually, so I record it for future learning use. After the function is created in Mysql, it will prompt the error message This func...

2020-04-14

Mysql连接远程数据库无法连接

解决办法

2020-05-22

Mysql指定用户访问特定数据库

今天使用新建用户访问云服务器的mysql发现一只报错并且只能访问infomation_schema数据库，按照博客上的办法输入指令grant all privileges on test_db.* to testuser@localhost identified by "123456" mysql一直报错一直按照博客上面进行赋予权限在报错，感觉应该是版本不一致导致的命令改变。果然，我在refman-8.0-en的说明文档中找到了这个命令由于刚接触mysql所以大部分依赖于博客和baidu，其实应该将这些查询办法与说明文档进行对照，不能一昧的相信单一解决办法导致把宝贵的工作时间浪费在无意义的debug中。