using主题的文章列表，还有using的技术要点_第7页

using static

C#引用命名空间，一般用using，那么usingstatic是什么东西呢?usingstatic除了命名空间，还可以在命名空间最后加一个类，这样后面可以直接使用这个类的：静态方法、类中类等。比如，以类中类来举例，原来是：usingItpow;Class1.Class2c=newClass1.Class2();现在可以...

代码星球 ·2023-04-16

Python错误 ValueError: If using all scalar values, you must pass an index.

在使用pandas，使用json（dict）数据类型创建DataFrame时错误 ValueError:Ifusingallscalarvalues,youmustpassanindex。这是因为pandas的DataFrame方法需要传入一个可迭代的对象(列表，元组，字典等)，或者给DataFrame指定i...

代码星球 ·2021-02-22

Using join buffer (Block Nested Loop)

Usingjoinbuffer(BlockNestedLoop)msyql的表连接算法走索引之后mysql>explainSELECTa.custid,b.score,b.xcreditscore,b.lrscoreFROM(SELECTDISTINCTcustidFROMsync.`credit_apply`W...

代码星球 ·2021-02-22

java.sql.SQLException: Access denied for user 'root'@'d001' (using password: YES)

在安装CDH的时候报错了：root@d001:/var/cache/yum/x86_64/7/base#/opt/cm-5.13.0/share/cmf/schema/scm_prepare_database.shmysqlcdh-hd001-uroot-proot-pwordemotion--scm-hostd001...

代码星球 ·2021-02-20

mysql中using

select*from(SELECTu.utm_source,count(DISTINCTu.mobile)asnew_user--登记用户FROM表名uWHEREu.created_timeBETWEEN'2019-03-0100:00:00'AND'2019-03-0123:59:59'andu.utm_sourc...

代码星球 ·2021-02-18

Access denied for user 'root'@'localhost' (using password:YES)解决方法

　　在MySQL的使用过程中，我们可能会碰到“Access denied for user 'root'@'localhost' (using password:YES)”的问题，那么接下来我们就来解决它。　　经过我的百度查询最后得出结论：出现这种错误有两种可...

代码星球 ·2021-02-17

c#：使用using关键字自动释放资源未必一定就会有明显好处

publicstringToXML(){stringstrXml=string.Empty;try{MemoryStreamms=newMemoryStream();XmlSerializerxml=newXmlSerializer(this.GetType());xml.Serialize(ms,this);byte...

代码星球 ·2021-02-16

Error Code: 1175. You are using safe update

使用MySQL执行update的时候报错：ErrorCode:1175.YouareusingsafeupdatemodeandyoutriedtoupdateatablewithoutaWHEREthatusesaKEYcolumnTodisablesafemode,toggletheoptioninPreferen...

代码星球 ·2021-02-13

MySQL root账户密码设为“root”后执行命令提示ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

修改root账户密码为“root”后，提示ERROR1820(HY000):YoumustresetyourpasswordusingALTERUSERstatementbeforeexecutingthisstatement.MySQL5.7加强了安全保障，以上意思是密码不符合安全策略要求，我们输入一个8位或以上长度...

代码星球 ·2021-02-12

解决 eclipse tomcat cannot create a server using the selected type

解决的方法1.退出eclipse；2.打开[工程目录下]/.metadata/.plugins/org.eclipse.core.runtime/.settings目录；3.删除org.eclipse.wst.server.core.prefs和org.eclipse.jst.server.tomcat.core.pr...

代码星球 ·2021-02-11

Consider using EXISTS instead of IN

https://www.red-gate.com/hub/product-learning/sql-prompt/consider-using-not-exists-instead-not-subqueryPhilFactorexplainswhyyoushouldpreferuseof[NOT]EXISTSover[...

代码星球 ·2021-02-08

How to Delete using INNER JOIN with SQL Server?

Youneedtospecifywhattableyouaredeletingfrom,hereisaversionwithanalias:DELETEwFROMWorkRecord2wINNERJOINEmployeeeONEmployeeRun=EmployeeNoWHERECompany='1'ANDDate='...

代码星球 ·2021-02-08

What's the difference between using “let” and “var” to declare a variable in JavaScript?

https://stackoverflow.com/questions/762011/whats-the-difference-between-using-let-and-var-to-declare-a-variable-in-javThedifferenceisscoping. var issc...

代码星球 ·2021-02-08

OAuth Implementation for ASP.NET Web API using Microsoft Owin.

http://blog.geveo.com/OAuth-Implementation-for-WebAPI2OAuthisanopenstandardfortokenbasedauthenticationandauthorizationoninternet.InsimpletermsOAuthprovidesawayf...

代码星球 ·2021-02-08

JSON Web Token in ASP.NET Web API 2 using Owin

http://bitoftech.net/2014/10/27/json-web-token-asp-net-web-api-2-jwt-owin-authorization-server/Inthepreviouspost DecoupleOWINAuthorizationServerfromResourc...

代码星球 ·2021-02-08