crud

来源： https://stackoverflow.com/questions/62846151/typeerror-cannot-read-property-db-of-undefined-while-trying-to-mongodb-atlas

问题 Scene : I am building a simple calendar web-app that uses React for the front-end and MySQL on the back-end for the server. The app retrieves a list of all the events from the server when it is first mounted, displays them to the user and allows for CRUD operations. Everything works as expected. Question : On a Create, Update or Delete operation, should I: Update the database and the state "independently". Update the database, make another call to the server to retrieve the new list of events

问题 Scene : I am building a simple calendar web-app that uses React for the front-end and MySQL on the back-end for the server. The app retrieves a list of all the events from the server when it is first mounted, displays them to the user and allows for CRUD operations. Everything works as expected. Question : On a Create, Update or Delete operation, should I: Update the database and the state "independently". Update the database, make another call to the server to retrieve the new list of events

问题 Scene : I am building a simple calendar web-app that uses React for the front-end and MySQL on the back-end for the server. The app retrieves a list of all the events from the server when it is first mounted, displays them to the user and allows for CRUD operations. Everything works as expected. Question : On a Create, Update or Delete operation, should I: Update the database and the state "independently". Update the database, make another call to the server to retrieve the new list of events

问题 Scene : I am building a simple calendar web-app that uses React for the front-end and MySQL on the back-end for the server. The app retrieves a list of all the events from the server when it is first mounted, displays them to the user and allows for CRUD operations. Everything works as expected. Question : On a Create, Update or Delete operation, should I: Update the database and the state "independently". Update the database, make another call to the server to retrieve the new list of events

问题 I have a PHP class called Product: class Product { $id; $name; } And another class that get data from database: $stm = $this->dsn->prepare($sql); $stm->execute(); $rst = $stm->fetchAll(PDO::FETCH_ASSOC); How can I convert this PDO resultset ($rst) to an array of objects Product? 回答1: Use the PDO::FETCH_CLASS argument. class Product { public $id; public $name; } $stm = $this->dsn->prepare($sql); $stm->execute(); $result = $stm->fetchAll( PDO::FETCH_CLASS, "Product" ); http://php.net/manual/en

问题 Hello Im currently using a third party package called django-river to implement a sort of workflow system into my application. The reason for using this is because it allows the user to dynamically generate workflows and attatch functions on the fly . Im currently using this across some of my models that require this functionality. However , there is one model that i wish to restrict this freedom. I do not wish to allow the user to add any instances than the one i have added from the start ,

问题 I am creating a little Spring REST service. I have a findById() call: @GetMapping("/items/{id}") MyItem one(@PathVariable String id) { return repository.findById(id).orElseThrow(() -> new MyItemNotFoundException(id)); } If there is no MyItem object with the given id , I am throwing an exception using the Optional<T>.orElseThrow() method. This is very useful and quite simple. Now I added a findAll() call from the PagingAndSorting<T, ID> repository: @GetMapping("/items") List<MyItem> all() {

问题 I am creating a little Spring REST service. I have a findById() call: @GetMapping("/items/{id}") MyItem one(@PathVariable String id) { return repository.findById(id).orElseThrow(() -> new MyItemNotFoundException(id)); } If there is no MyItem object with the given id , I am throwing an exception using the Optional<T>.orElseThrow() method. This is very useful and quite simple. Now I added a findAll() call from the PagingAndSorting<T, ID> repository: @GetMapping("/items") List<MyItem> all() {

问题 I am recently working on making a Java web application, which must focus on CRUD(You know). But I am stuck with the read & update & delete operations(Three operations). Only Create Operation works fine. In detailed, the Java web application I am working on is not completed so far. Inside my code, the function called "findUsers" is used to implement read operation. By the way, I already checked code for a long period of time. I guess the problem may be in findUsers function(not sure, just an