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C 语言的输入输出函数 scanf() 和 printf()

scanf&printfC语言入门的第一堂课讲的就是输出 Hello,world! 字符串,使用 printf() 输出到黑框框(命令行)里。后面讲IO的时候又提到了 scanf() 从黑框框中获取输入的内容。基本的用法如下:intn;scanf("%...

navicat查看数据库

Navicat是一款功能强大的数据库管理工具,它支持多种类型的数据库,包括MySQL、Oracle、SQLServer等。通过Navicat,你可以方便地查看和管理数据库。在Navicat中查看数据库的步骤如下:1.打开Navicat软件,并连接到数据库服务器。在连接窗口中输入正确的服务器地址、端口号、用户名和密码,然...
开发笔记 开发笔记·2024-01-09

available: expected at least 1 bean which qualifies as autowire candidate

available:expectedatleast1beanwhichqualifiesasautowirecandidate这个错误我也是找了半天,最后排查的时候发现是自己的实现类写错了,所以注入不进去.出现这个错误一般有四个方向排查查看接口实现类是否加入注解,如service、repository等查看spring...

PHP 开启 Opcache

Opcache能够将代码编译成字节码,能够加快脚本的运行。检查是否安装opcache:php-vPHP7.3.22(cli)(built:Sep3202021:16:44)(NTS)Copyright(c)1997-2018ThePHPGroupZendEnginev3.3.22,Copyright(c)1998-20...
开发笔记 开发笔记·2023-08-12

前端如何用 canvas 来做电影院选票功能

电影院选票功能可以通过Canvas来实现,具体实现步骤如下:绘制座位图案:使用Canvas绘制座位图案,可以用矩形或圆形来表示每个座位,还可以添加不同颜色来表示该座位的状态(已售、已选、可选等)。添加鼠标事件:添加鼠标事件,如鼠标移动、鼠标单击等,来实现用户交互操作。例如,当用户点击座位时,将该座位的状态改为已选状态,...

ORA-56722: I/O request limit exceeded – call aborted

文档解释ORA-56722:I/Orequestlimitexceeded–callabortedCause:TheResourceManagerSWITCH_IO_REQSlimitwasexceeded.Action:Reducethecomplexityoftheupdateorquery,orcon...

ORA-41689: invalid collection specification in the rule condition

文档解释ORA-41689:invalidcollectionspecificationintheruleconditionCause:Anattemptwasmadetoinsertaruleconditionwithinvalidcollectionelementspecification.Action:Corre...

ORA-54534: incorrect box surface due to wrong specification

文档解释ORA-54534:incorrectboxsurfaceduetowrongspecificationCause:TheelemInfodefinitionwasnotcorrectforthesurfaceoftheaxisalignedbox.Action:Changetheinterpretationt...

ORA-64143: Can only share an existing XMLIndex table with an XMLTYPE column.

文档解释ORA-64143:CanonlyshareanexistingXMLIndextablewithanXMLTYPEcolumn.Cause:AnattemptwasmadetoshareatablewithoutanXMLTYPEcolumn.Action:DropthegroupcontainingtheX...
IT技术学习 IT技术学习·2023-07-28

ORA-44739: Cannot drop the last group.

文档解释ORA-44739:Cannotdropthelastgroup.Cause:Anattemptwasmadetodropthelastgroupintheindex.Action:UsetheDROPINDEXstatementinstead.ORA-44739是Oracle数据库中的一个错误代码。它表明,用...

ORA-38471: ROWIDs for table aliases cannot be null

文档解释ORA-38471:ROWIDsfortablealiasescannotbenullCause:Anattemptwasmadetopassanullvalueforthetablealiasattributeinthedataitem,whichisnotpermitted.Action:Passavali...

ORA-44747: An XMLIndex with a structured component cannot be specified with ASYNC.

文档解释ORA-44747:AnXMLIndexwithastructuredcomponentcannotbespecifiedwithASYNC.Cause:AnattemptwasmadetospecifyASYNCparameterforanXMLIndexwithastructuredcomponent.Ac...

ORA-38810: Implementation restriction: cannot drop edition that has a parent and a child

文档解释ORA-38810:Implementationrestriction:cannotdropeditionthathasaparentandachildCause:Thiserroroccurredbecauseanattemptwasmadetodropaneditionthathasaparentandac...

ORA-53213: cannot access DICOM data with invalid source type

文档解释ORA-53213:cannotaccessDICOMdatawithinvalidsourcetypeCause:AninvalidsourcetypewasstoredinthesourceattributeoftheORDDicomobject.Action:SeetheOracleMultimediad...

ORA-31048: Unsaved resources cannot be updated

文档解释ORA-31048:UnsavedresourcescannotbeupdatedCause:Anattemptwasmadetoupdatearesourcethatwasneversavedtodisk.Action:Performaresourceinsertioninstead.ORA-31048:Un...
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