#Null

null和undefined的区别

null和undefined都是js中的特殊值,表示缺失或未定义的值。null表示一个空对象指针,即该变量本应该指向一个对象,但是现在没有指向任何一个对象。例如:varobj=null;undefined表示一个未定义的值,即该变量没有被赋值或者被赋值为undefined。例如:varx;console.log(x);...
开发笔记 ·2024-07-02

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

ORA-38471: ROWIDs for table aliases cannot be null

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

ORA-32150: Cannot perform operation on a null timestamp

文档解释ORA-32150:CannotperformoperationonanulltimestampCause:Thetimestampinvolvedinthisoperationisnull.Action:Usevalid,non-nulltimestampinstancetoperformthisoperat...

ORA-25127: RELY not allowed in NOT NULL constraint

文档解释ORA-25127:RELYnotallowedinNOTNULLconstraintCause:AnattempttosetRELYonforNOTNULLconstraint.Action:onlyNORELYmaybespecifiedforaNOTNULLconstraint.ORA-25127是一个O...
IT技术学习 ·2023-07-28

ORA-30625: method dispatch on NULL SELF argument is disallowed

文档解释ORA-30625:methoddispatchonNULLSELFargumentisdisallowedCause:AmembermethodofatypeisbeinginvokedwithaNULLSELFargument.Action:Changethemethodinvocationtopassin...

ORA-48474: Syntax error specifying product, must not be NULL

文档解释ORA-48474:Syntaxerrorspecifyingproduct,mustnotbeNULLCause:Theproductclauseisbeingused,butnoproductnameisprovidedAction:SupplytheproductnameORA-48474是一个表示系统无...

ORA-22957: NULL is an invalid input to powermultiset and COLLECT functions

文档解释ORA-22957:NULLisaninvalidinputtopowermultisetandCOLLECTfunctionsCause:NULLwasgivenasinputtothepowermultisetorCOLLECTfunction.Action:Giveanon-nullvalueasinpu...
IT技术学习 ·2023-07-28

ORA-23430: argument “string” cannot be NULL or empty string

文档解释ORA-23430:argument“string”cannotbeNULLoremptystringCause:ThecallerhasprovidedanargumentwhosevaluecannotbeNULLortheemptystring.Action:Checkthatth...

ORA-13910: Parameter string cannot be NULL.

文档解释ORA-13910:ParameterstringcannotbeNULL.Cause:AnattemptwasmadetocallGET_THRESHOLDprocedurewithoutarequiredparameter.Action:Specifyavalidvalueforthisparameter....

ORA-31057: Display Name of the element being inserted is null

文档解释ORA-31057:DisplayNameoftheelementbeinginsertedisnullCause:TheDisplayNameoftheelementwhichisbeinginsertedintotheRESOURCE_VIEWisnullAction:SpecifytheDisplayNa...
IT技术学习 ·2023-07-27

ORA-32117: Source LOB is null

文档解释ORA-32117:SourceLOBisnullCause:ThesourceLOBinstanceonwhichtheoperationwasattemptedwasnull.Action:Useavalid,non-nullsourceLOBinstanceforthisoperation.ORA-321...
IT技术学习 ·2023-07-27

ORA-32144: Cannot perform operation on a null interval

文档解释ORA-32144:CannotperformoperationonanullintervalCause:Theintervalinvolvedinthisoperationisnull.Action:Usevalid,non-nullintervalinstancetoperformthisoperation...

ORA-32113: Null object passed

文档解释ORA-32113:NullobjectpassedCause:Nullobjectwaspassed.Action:Passanon-nullobject.ORA-32113:Null对象传递官方解释ORA-32113:null对象传递。一个空引用(Null)对象传递到一个可能使用它的地方。使用null对象类...
IT技术学习 ·2023-07-26

ORA-32114: Cannot perform operation on a null LOB

文档解释ORA-32114:CannotperformoperationonanullLOBCause:TheLOBinstanceonwhichtheoperationwasattemptedwasnull.Action:Useavalid,non-nullLOBinstancetoperformthisoperat...
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