#AB

nullable是什么意思

nullable是一个概念,它指的是可以被设置为null的值。它可以用来表示一个变量或者一个属性的值不存在,或者说这个值本身就是null。在编程语言中,nullable通常用于表示一个变量或者属性的值不存在,或者说这个值本身就是null。例如,在Java中,你可以使用“?”来声明一个变量是nul...
开发笔记 ·2023-12-02

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...

Reachability(判断网络是否连接)

类似于一个网络状况的探针。  [[NSNotificationCenterdefaultCenter]addObserver:selfselector:@selector(reachabilityChanged:)name:kReachabilityChangedNotificationobject:nil];&nbs...

ChatGPT Signup is currently unavailable错误提示解决方法

问题介绍:1、账号注册阶段出现的提示:Signupiscurrentlyunavailable,pleasetryagainlater2、翻译过来错误原因是:注册当前不可用,请稍后再试,是一个比较常见的报错内容; 解决方法:使用QQ邮箱注册。1、出现这一问题最大的原因是因为邮箱导致的;2、网易以及163邮箱都...

Matlab中length函数的详解

一、Matlab中length函数用法Matlab中的length函数用于返回一个向量或矩阵中的元素数量。一般来说,如果向量或矩阵的行数或列数中较小的那个为1,则length函数返回较大的那个维度的长度。例如,对于一个向量来说,length函数返回该向量的元素个数;而对于一个矩阵来说,length函数返回该矩阵的行数和...
开发笔记 ·2023-08-01

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-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 ·2023-07-28

ORA-38471: ROWIDs for table aliases cannot be null

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

ORA-39034: Table string does not exist.

文档解释ORA-39034:Tablestringdoesnotexist.Cause:TheuserreferencedatableinanAPIthatdidnotexist.Action:CorrecttablenameandretryAPI.ORA-39034:Tablestringdoesnotexist.这...

ORA-32415: fast refreshable remote materialized view on a detail table with commit SCN-based materialized view log is not supported

文档解释ORA-32415:fastrefreshableremotematerializedviewonadetailtablewithcommitSCN-basedmaterializedviewlogisnotsupportedCause:Thematerializedviewcreationfailedbeca...

ORA-26028: index string.string initially in unusable state

文档解释ORA-26028:indexstring.stringinitiallyinunusablestateCause:AnindexisinIUstatepriortothebeginningofadirect*pathload,itcannotbemaintainedbytheloader.Action:Eit...

ORA-31181: PL/SQL DOM handle accesses node that is no longer available

文档解释ORA-31181:PL/SQLDOMhandleaccessesnodethatisnolongeravailableCause:Thespecifiedpl/sqlhandleisreferencinganodeinaDOMDocumentthatisnolongeravailable.Action:Ens...
IT技术学习 ·2023-07-28

ORA-25100: TABLESPACE option can only be used with ALTER INDEX REBUILD

文档解释ORA-25100:TABLESPACEoptioncanonlybeusedwithALTERINDEXREBUILDCause:TheTABLESPACEoptiontoALTERINDEXwasusedwithouttheREBUILDoption.Action:UseALTERINDEXREBUILDT...

ORA-44742: Cannot alter columns of a table that is shared by other group(s).

文档解释ORA-44742:Cannotaltercolumnsofatablethatissharedbyothergroup(s).Cause:Anattemptwasmadetoaddcolumnsto,modifycolumnsof,ordropcolumnsfromatablesharedbyothergro...

ORA-38734: Flashback log is inconsistent; belongs to another database.

文档解释ORA-38734:Flashbacklogisinconsistent;belongstoanotherdatabase.Cause:ThedatabaseIDintheflashbackdatabaselogfiledidnotmatchthedatabaseIDinthecontrolfile.Actio...
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