inheritance

问题 So I want to execute a filter on all Columns of my Database Model which uses table inheritance. I am by no means sure if this is actually do-able or not. To get started let's use the same inheritance example from the SQLAlchemy Doc just slightly modified. I've omitted the imports here. class Employee(Base): __tablename__ = 'employee' id = Column(Integer, primary_key=True) name = Column(String(50)) type = Column(String(50)) __mapper_args__ = { 'polymorphic_identity':'employee', 'polymorphic_on

问题 So to be more exact. I am currently learning Flask from Corey Schafers tutorial series and I am in the phase of Login Authentication, everything seemed to be fine, but then I got this error after trying to log in: AttributeError AttributeError: 'User' object has no attribute 'is_active' Traceback (most recent call last) File "C:\Users\panda\Desktop\HDD\Programs\Python3\Lib\site-packages\flask\app.py", line 2463, in __call__ return self.wsgi_app(environ, start_response) File "C:\Users\panda

问题 In my typescript I'm trying to create/clone an child-object via a method in the base-class. This is my (simplified) setup. abstract class BaseClass<TCompositionProps> { protected props: TCompositionProps; protected cloneProps(): TCompositionProps { return $.extend(true, {}, this.props); } // can be overwriten by childs constructor(props: TCompositionProps){ this.props = props; } clone(){ const props = this.cloneProps(); return this.constructor(props); } } interface IProps { someValues: string

问题 In the .net framework, there's a generic IEnumerable<T> interface which inherits from the not-generic IEnumerable , and they both have a GetEnumerator() method. The only differents between these two GetEnumerator() is the return type. Now I have a similar design, but when I compile the code, the compiler said: MyInterface<T>.GetItem() ' hides inherited member ' MyInterface.GetItem() '. Use the new keyword if hiding was intended. The MyInterface<T>.GetItem() returns a concrete type T, while

问题 In the .net framework, there's a generic IEnumerable<T> interface which inherits from the not-generic IEnumerable , and they both have a GetEnumerator() method. The only differents between these two GetEnumerator() is the return type. Now I have a similar design, but when I compile the code, the compiler said: MyInterface<T>.GetItem() ' hides inherited member ' MyInterface.GetItem() '. Use the new keyword if hiding was intended. The MyInterface<T>.GetItem() returns a concrete type T, while

问题 In my project, lombok is used to avoid writing getters and setters for a class. I have two classes Child extends Parent : @Value @Builder @AllArgsConstructor @JsonIgnoreProperties(ignoreUnknown = true) public class Parent { @Nonnull @JsonProperty("personId") private final String personId; @JsonProperty("personTag") private final String personTag; ... } And @Value @Builder @AllArgsConstructor @JsonIgnoreProperties(ignoreUnknown = true) public class Child extends Parent { @Nonnull @JsonProperty

问题 I'd like to subclass MKCircle (e.g. MyCircle ) by adding another String property, let's call it " code ". This property shall not be an optional and constant, so I have to set it from an initializer, right? Of course MyCircle should also get center coordinate and the radius. These two properties are read-only, so I also need to set them via initializer. In the end I need an initializer that takes 3 parameters: coordinate , radius and code . Sounds pretty easy but Swifts designated and

问题 I'd like to subclass MKCircle (e.g. MyCircle ) by adding another String property, let's call it " code ". This property shall not be an optional and constant, so I have to set it from an initializer, right? Of course MyCircle should also get center coordinate and the radius. These two properties are read-only, so I also need to set them via initializer. In the end I need an initializer that takes 3 parameters: coordinate , radius and code . Sounds pretty easy but Swifts designated and

问题 I'd like to subclass MKCircle (e.g. MyCircle ) by adding another String property, let's call it " code ". This property shall not be an optional and constant, so I have to set it from an initializer, right? Of course MyCircle should also get center coordinate and the radius. These two properties are read-only, so I also need to set them via initializer. In the end I need an initializer that takes 3 parameters: coordinate , radius and code . Sounds pretty easy but Swifts designated and

问题 Currently, I am trying the new extends feature in the tsconfig.json that allows developers to have a base tsconfig.json, that other modules can extend / modify. It is working, although not as expected. Somehow, the only way to get this working is to specifiy compileroptions.lib in both parent and child configs. parent.tsconfig.json { "compilerOptions": { "target": "es5", "module": "commonjs", "moduleResolution": "node", "emitDecoratorMetadata": true, "experimentalDecorators": true, "sourceMap