Auto type column schema
时间: 2023-07-26 11:03:55 浏览: 24
可以使用以下的 SQL 语句来查询数据库中某张表的列名和数据类型:
```
SELECT column_name, data_type
FROM information_schema.columns
WHERE table_name = 'table_name';
```
其中,`table_name` 是你想要查询的表名。这个 SQL 语句将返回一个包含列名和数据类型的结果集。你可以根据需要对这个结果集进行进一步的处理和分析。
相关问题
can’t set auto_increment
As an AI language model, I do not have the ability to directly access or manipulate databases. However, here are some possible reasons why you may be unable to set auto_increment:
1. The column you are trying to set as auto_increment is not a primary key or unique index.
2. The table already contains data, and the values in the auto_increment column conflict with existing values.
3. The auto_increment value has reached its maximum limit for the data type used.
4. The user account does not have the required privileges to modify the table schema.
To resolve this issue, you may need to check your table structure and data, adjust the data type or limit of the auto_increment column, or grant the necessary privileges to the user account.
<?xml version="1.0" encoding="utf-8" ?> <nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd" autoReload="true" throwExceptions="false" internalLogLevel="Off" internalLogFile="c:\temp\nlog-internal.log"> <!-- optional, add some variables https://github.com/nlog/NLog/wiki/Configuration-file#variables --> <variable name="myvar" value="myvalue"/> <!-- See https://github.com/nlog/nlog/wiki/Configuration-file for information on customizing logging rules and outputs. --> <targets> <!-- add your targets here See https://github.com/nlog/NLog/wiki/Targets for possible targets. See https://github.com/nlog/NLog/wiki/Layout-Renderers for the possible layout renderers. --> <!-- Write events to a file with the date in the filename. <target xsi:type="File" name="f" fileName="${basedir}/logs/${shortdate}.log" layout="${longdate} ${uppercase:${level}} ${message}" /> --> <target xsi:type="File" name="f" fileName="logs/${shortdate}.log" archiveFileName="logs/archive.{#}.log" archiveEvery="Day" archiveNumbering="Rolling" maxArchiveFiles="30" concurrentWrites="true" keepFileOpen="false" encoding="utf-8"> <layout xsi:type="CsvLayout" delimiter="auto" withHeader="true" > <column name="time" layout="${longdate:universalTime=false}" /> <column name="threadid" layout="${threadid}"/> <column name="level" layout="${level:upperCase=true}"/> <column name="callsite" layout="${callsite:includeSourcePath=true}" /> <column name="message" layout="${message}" /> <column name="stacktrace" layout="${callsite:includeSourcePath=true}" /> <column name="exception" layout="${exception:format=ToString}"/> </layout> </target> <target xsi:type="File" name="c" layout="${threadid} ${uppercase:${level}} ${message} ${callsite} ${exception:format=tostring}" /> </targets> <rules> <!-- add your logging rules here --> <!-- Write all events with minimal level of Debug (So Debug, Info, Warn, Error and Fatal, but not Trace) to "f" <logger name="*" minlevel="Debug" writeTo="f" /> --> <logger name="*" writeTo="f,c" /> </rules> </nlog>NLog这个配置给我怎么加注释说明
在NLog配置文件中添加注释可以使用XML的注释标记`<!-- 注释内容 -->`,例如:
```
<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd"
autoReload="true"
throwExceptions="false"
internalLogLevel="Off"
internalLogFile="c:\temp\nlog-internal.log">
<!-- 定义变量 -->
<variable name="myvar" value="myvalue"/>
<!-- 定义日志输出目标 -->
<targets>
<!-- 文件日志 -->
<target xsi:type="File" name="f" fileName="logs/${shortdate}.log"
archiveFileName="logs/archive.{#}.log"
archiveEvery="Day"
archiveNumbering="Rolling"
maxArchiveFiles="30"
concurrentWrites="true"
keepFileOpen="false" encoding="utf-8">
<layout xsi:type="CsvLayout" delimiter="auto" withHeader="true" >
<column name="time" layout="${longdate:universalTime=false}" />
<column name="threadid" layout="${threadid}"/>
<column name="level" layout="${level:upperCase=true}"/>
<column name="callsite" layout="${callsite:includeSourcePath=true}" />
<column name="message" layout="${message}" />
<column name="stacktrace" layout="${callsite:includeSourcePath=true}" />
<column name="exception" layout="${exception:format=ToString}"/>
</layout>
</target>
<!-- 控制台日志 -->
<target xsi:type="File" name="c" layout="${threadid} ${uppercase:${level}} ${message} ${callsite} ${exception:format=tostring}" />
</targets>
<!-- 定义日志输出规则 -->
<rules>
<logger name="*" writeTo="f,c" />
</rules>
</nlog>
```
在需要注释的地方添加注释即可,例如:
```
<!-- 定义变量 -->
<variable name="myvar" value="myvalue"/>
<!-- 定义日志输出目标 -->
<targets>
<!-- 文件日志 -->
<target xsi:type="File" name="f" fileName="logs/${shortdate}.log"
archiveFileName="logs/archive.{#}.log"
archiveEvery="Day"
archiveNumbering="Rolling"
maxArchiveFiles="30"
concurrentWrites="true"
keepFileOpen="false" encoding="utf-8">
<layout xsi:type="CsvLayout" delimiter="auto" withHeader="true" >
<column name="time" layout="${longdate:universalTime=false}" />
<column name="threadid" layout="${threadid}"/>
<column name="level" layout="${level:upperCase=true}"/>
<column name="callsite" layout="${callsite:includeSourcePath=true}" />
<column name="message" layout="${message}" />
<column name="stacktrace" layout="${callsite:includeSourcePath=true}" />
<column name="exception" layout="${exception:format=ToString}"/>
</layout>
</target>
<!-- 控制台日志 -->
<target xsi:type="File" name="c" layout="${threadid} ${uppercase:${level}} ${message} ${callsite} ${exception:format=tostring}" />
</targets>
<!-- 定义日志输出规则 -->
<rules>
<logger name="*" writeTo="f,c" />
</rules>
```
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