parent-child | 易学教程

PHP hierarchical array - Parents and childs

阅读更多关于 PHP hierarchical array - Parents and childs

问题 I use PHP and mySQL with Idiorm. That might not be relevant. My PHP array It's a relationship between parents and childs. 0 is the root parent. Example: Root parent 0 have the child 33 which have the child 27 which have the child 71. This array structure can be changed if needed for solving the problem. array ( 33 => array ( 0 => '27', 1 => '41', ), 27 => array ( 0 => '64', 1 => '71', ), 0 => array ( 0 => '28', 1 => '29', 2 => '33', ), ) My hierarchical result Something like this, but as an

node.js child process - difference between spawn & fork

阅读更多关于 node.js child process - difference between spawn & fork

问题 This might seem like a basic question, but I could not find any documentation : What is the difference between forking & spawning a node.js process? I have read that forking is a special case of spawning, but what are the different use cases / repecussions for using each of them? 回答1: Spawn is a command designed to run system commands. When you run spawn, you send it a system command that will be run on its own process, but does not execute any further code within your node process. You can

Selecting second children of first div children in javascript [duplicate]

阅读更多关于 Selecting second children of first div children in javascript [duplicate]

问题 This question already has answers here : querySelector with nested nth-child in Chrome doesn't appear to work (2 answers) Closed 8 months ago . I have an html that look something like this: <div id="mainDiv"> <-- I have this <div> <div></div> <div></div> <-- I need to get this </div> <span></span> <more stuff /> </div> i am using: var mainDiv = document.getElementById('mainDiv'); because I need that div in a var, but i also need to get that second div on the first div inside mainDiv into a

Passing props to React Router children routes

阅读更多关于 Passing props to React Router children routes

问题 I'm having trouble overcoming an issue with react router. The scenario is that i need to pass children routes a set of props from a state parent component and route. what i would like to do is pass childRouteA its propsA , and pass childRouteB its propsB . However, the only way i can figure out how to do this is to pass RouteHandler both propsA and propsB which means every child route gets every child prop regardless of whether its relevant. this isnt a blocking issue at the moment, but i can

Hibernate @OneToMany with mappedBy (parent-child) relationship and cache problem

阅读更多关于 Hibernate @OneToMany with mappedBy (parent-child) relationship and cache problem

问题 I have this problem for a long time now, I have searched the web and SO in and out and didn't find a solution yet. I hope you can help me on that. I have a parent-child relationship between two entities like the following: @Entity public class Parent { // ... @OneToMany(mappedBy = "parent", fetch = FetchType.LAZY, cascade = CascadeType.REMOVE) private Set<Child> children = new HashSet<Child>(); // ... } @Entity public class Child { // ... @ManyToOne(fetch = FetchType.LAZY) private Parent

How to append a childnode to a specific position

阅读更多关于 How to append a childnode to a specific position

问题 How can I append a childNode to a specific position in javascript? I want to add a childNode to the 3rd position in a div. There are other nodes behind it that need to move backwards (3 becomes 4 etc.) 回答1: You can use .insertBefore(): parentElement.insertBefore(newElement, parentElement.children[2]); 回答2: For this you have 3 options .insertBefore(), .insertAdjacentElement() or .insertAdjacentHtml() .insertBefore() var insertedElement = parentElement.insertBefore(newElement, referenceElement)

How do I enable Parts/Components in Unity C# with only a game object in the script

阅读更多关于 How do I enable Parts/Components in Unity C# with only a game object in the script

问题 I am using Photon to make put multiplayer in my game, to ensure that one player doesn't control them all, when you spawn in, client side it will activate your scripts/camera so you can see and move. Although I can't think of a way around this problem, since I don't know how to enable/disable children's components or enable a child's child. I want to enable this through scripting http://imgur.com/ZntA8Qx and this http://imgur.com/Nd0Ktoy My script is this: using UnityEngine; using System

Are child processes created with fork() automatically killed when the parent is killed?

阅读更多关于 Are child processes created with fork() automatically killed when the parent is killed?

I'm creating child processes with fork() in C/C++. When the parent process ends (or is killed for some reason) I want all child processes to be killed as well. Is that done automatically by the system? Or I have to do it myself? Thanks. Pre-existing similar questions: How can I cause a child process to exit when the parent does? How to make child process die after parent exits? Johannes Schaub - litb No. If the parent is killed, children become children of the init process (that has the process id 1 and is launched as the first user process by the kernel). The init process checks periodically

How do I add child items dynamically to an expandable listview.?

阅读更多关于 How do I add child items dynamically to an expandable listview.?

问题 For example, I have an edit text and a button. When the button is pressed the text is added to the first group in my expandable listview and each following item is added underneath it. Thank you. (If you need the code I have so far please request.) 回答1: first one you should create your own custom adapter. once create a class like this. public class ExpandableListParentClass{ private Object parent; private ArrayList<Object> parentChildren; public ExpandableListParentClass() { } public

What happens to a SIGINT (^C) when sent to a perl script containing children?

阅读更多关于 What happens to a SIGINT (^C) when sent to a perl script containing children?

问题 I have a Perl script that forks. Each fork runs an external program, parses the output, and converts the output to a Storable file. The Storable files are then read in by the parent and the total data from each of the children are analyzed before proceeding onto a repeat of the previous fork or else the parent stops. What exactly happens when I issue a ^C while some of the children are still running the external program? The parent perl script was called in the foreground and, I presume,