fetch | 易学教程

[Cocoa]深入浅出 Cocoa 之 Core Data（1）- 框架详解

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Core data 是 Cocoa 中处理数据，绑定数据的关键特性，其重要性不言而喻，但也比较复杂。Core Data 相关的类比较多，初学者往往不太容易弄懂。计划用三个教程来讲解这一部分：框架详解：讲解 Core data 框架，运作过程，设计的类； Core data应用程序示例：通过生成一个使用 Core data 的应用程序来讲解如何在 XCode 4 中使用 Core data。手动创建Core data示例：不利用框架自动生成代码，完全自己编写所有的 Core data 相关代码的命令行应用程序来深入讲解 Core data的使用。本文为第一部份：框架详解一，概观下面先给出一张类关系图，让我们对它有个总体的认识。在上图中，我们可以看到有五个相关模块： 1， Managed Object Model Managed Object Model 是描述应用程序的数据模型，这个模型包含实体（Entity），特性（Property），读取请求（Fetch Request）等。（下文都使用英文术语。） 2，Managed Object Context Managed Object Context 参与对数据对象进行各种操作的全过程，并监测数据对象的变化，以提供对 undo/redo 的支持及更新绑定到数据的 UI。 3，Persistent Store

Hibernate JOIN FETCH - Objects appear multiple times in Resultset

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问题 I am using Spring JPA and Hibernate to build a REST API. I am searching for 2 days, but i didn't find any solution to fix this issue. In some queries i have multiple JOIN FETCH clauses. When I execute my query i have the parent object multiple times in my result set, in fact exactly as often as the father has children. Example: @Query("SELECT DISTINCT p AS post," + " <some subquery>" + "FROM Post p JOIN FETCH p.user u LEFT JOIN FETCH p.linkedUsers INNER JOIN FETCH p.track track " "WHERE ( (

Importing a Database to MATLAB error

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问题 I am trying to import tables to my MATLAB workspace and it keeps throwing me an error, "Undefined function or method 'fetch' for input arguments of type 'struct'. " This is my code that i am trying to execute: dyn_conformer = exec(conn, 'SELECT * FROM dyn_conformer'); rs =fetch(dyn_conformer); When i opened the object in the workspace, it stated that it was "Invalid or closed connection" . However, previously i manage to import other tables and it seemed to execute perfectly (they are stored

Fetch API default cross-origin behavior

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问题 The Fetch Specifications say that the default Fetch mode is 'no-cors' - A request has an associated mode, which is "same-origin", "cors", "no-cors", "navigate", or "websocket". Unless stated otherwise, it is "no-cors". But, I seem to be noticing this behavioral difference between mode: 'no-cors' and an unspecified mode. As demonstrated in this JSFiddle sample, explicitly defining mode as 'no-cors' makes the response inaccessible to the Javascript, while not specifying a mode makes the

Queryover dynamic fetch with joins

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问题 iam trying a new query with nhibernate and find a new problem :( take this as model: public class D { int id; } public class C { int id; } public class B { int id; ICollection<C> Cs; ICollection<D> Ds; } public class A { int id; ICollection<B> Bs; } i want A object that have a particular B object and dinamically eager fetch Cs or Ds collection of selected B: public virtual A Read(int idB, params Expression<Func<Attivita, object>>[] eagerFields) i start with IEnumerable<A> query = _session

PHP MYSQL $row[$variable]

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问题 I am trying to work around with dynamic table creation and data fetching. I am trying to get the data using following code : $myQuery = "SELECT ".$col_name." FROM ".$tabname." WHERE sampleid='".$sid."'"; $result = mysql_query($myQuery); $row = mysql_fetch_array($result); echo "<br>".$row['$col_name']; But, I am unable to get any data back. I checked printing the query and running it in php my admin and its working as I want. But I guess variable in array might not be working I guess. Please

Custom Request Headers not being sent with a JavaScript Fetch Request

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问题 I am trying to use JavaScripts Fetch() API to send an AJAX request to my PHP OAuth server. My issue is that I need to send a Request header Authorization with 'Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImp0aSI6IjM3MWFjZTRiZWE1NmViZDQ5YzQ1OTFkMmJiY2E4NGMwOTM2N2JiMjZmNjZiMmJkOTkxZmE3YmU0NTJjYWZmODBkMmZlYmJhYjFjNzMyMmM1In0

Multiple fetch requests with setState in React

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问题 I'm writing a component that will make fetch requests to two different paths of a site, then set its states to the resulting response data. My code looks something like this: export default class TestBeta extends React.Component { constructor(props){ super(props); this.state = { recentInfo: [], allTimeInfo: [] }; } componentDidMount(){ Promise.all([ fetch('https://fcctop100.herokuapp.com/api/fccusers/top/recent'), fetch('https://fcctop100.herokuapp.com/api/fccusers/top/alltime') ]) .then((

git pull 与git fetch的区别

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从百度上看到很多关于git fetch 和 git pull 的不同实践一下：从github上新建一个项目try， copy到本地。在github网站里修改readme.txt文件，新增加一句【 alter readme】在本地仓库的readme.txt也新增加一句，【add some thing】现在想把本地代码提交到github上，是不能提交的。会出现错误提示！！！应该先从远程仓库中把代码下载下来（1）用git pull会怎么样呢？ git pull origin master 打开本地仓库的readme.txt文件 git pull ：相当于是从远程获取最新版本并merge到本地（2）使用git fetch命令接着上面的，我们把冲突的代码改了，再提交上去再在readme.txt文件上增加use fetch 在本地仓库的readme.txt文件修改，增加use fetch loca l 本地提交代码，并提交代码，由上面可知，不能提交上去输入 git fetch origin master 打开readme.txt文件，没有任何变化我们再输入 git log -p master..origin/master 可以查看远程仓库中，是谁修改了代码，和怎样修改然后输入 git merge origin/master 手动merge仓库

js fetch

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https://www.jianshu.com/p/c2db35881b1a let myHeaders = new Headers(); myHeaders.append('Content-Type', 'image/jpeg'); let resource = new Request('flowers.jpg'); var init ={ "method":'GET', "headers":myHeaders, // headers: { // 'Content-Type': 'image/jpeg' // }, "body":, "mode":'cors', "credentials":"omit",//要用于请求的请求凭据:omit, same-origin, include。若要自动发送当前域的cookie，请使用此选项 "cache":'default', "redirect":"follow",//要使用的重定向模式：follow(自动跟随重定向)，error(如果发生重定向，则中止并显示错误)或manual(手动处理重定向)。在Chrome中，默认值为`follow'(在Chrome 47之前默认为`manual')。 "referrer":"client", "referrerPolicy":"no-referrer",//指定引用HTTP标头的值。可以是no