hierarchical-data

问题 If my JSON data looks like this: { "name": "root", "children": [ { "name": "a", "children": [ { "name": "b", "children": [ { "name": "c", "size": "1" }, { "name": "d", "size": "2" } ] }, { "name": "e", "size": 3 } ] }, { "name": "f", "children": [ { "name": "g", "children": [ { "name": "h", "size": "1" }, { "name": "i", "size": "2" } ] }, { "name": "j", "size": 5 } ] } ] } How can I return two adjacent levels in Python? For example return: a - b,e f - g,j The data could become very large,

问题 If my JSON data looks like this: { "name": "root", "children": [ { "name": "a", "children": [ { "name": "b", "children": [ { "name": "c", "size": "1" }, { "name": "d", "size": "2" } ] }, { "name": "e", "size": 3 } ] }, { "name": "f", "children": [ { "name": "g", "children": [ { "name": "h", "size": "1" }, { "name": "i", "size": "2" } ] }, { "name": "j", "size": 5 } ] } ] } How can I return two adjacent levels in Python? For example return: a - b,e f - g,j The data could become very large,

问题 If my JSON data looks like this: { "name": "root", "children": [ { "name": "a", "children": [ { "name": "b", "children": [ { "name": "c", "size": "1" }, { "name": "d", "size": "2" } ] }, { "name": "e", "size": 3 } ] }, { "name": "f", "children": [ { "name": "g", "children": [ { "name": "h", "size": "1" }, { "name": "i", "size": "2" } ] }, { "name": "j", "size": 5 } ] } ] } How can I return two adjacent levels in Python? For example return: a - b,e f - g,j The data could become very large,

问题 We are using PHP / SQL to build a parts database which will output as a tree structure. After plunging head first into the coding with the nested sets model we realised that we needed to adjust the model to allow for multiple parents. Effectively, every child can have more than one parent, and every parent can have more than one child, but each node cannot be its own relative. We want to link a collection of parts (A) to a parent part and create a larger part (B) whilst keeping the original

问题 I am trying to build a database with Cloud Firestore and having read the documentation about hierarchic structure I have found another solution to the one present in the documentation example. I have a collection of categories, and each category can have subcategories. Whereas I could use the system provided in the Firestore documentation example such as collection/document/subcollection/document... I have found another example for MongoDB where instead of having subcollections it uses nested

问题 I am trying to convert this structure: var initial = [ { Phase: "Phase 1", Step: "Step 1", Task: "Task 1", Value: "5" }, { Phase: "Phase 1", Step: "Step 1", Task: "Task 2", Value: "10" }, { Phase: "Phase 1", Step: "Step 2", Task: "Task 1", Value: "15" }, { Phase: "Phase 1", Step: "Step 2", Task: "Task 2", Value: "20" }, { Phase: "Phase 2", Step: "Step 1", Task: "Task 1", Value: "25" }, { Phase: "Phase 2", Step: "Step 1", Task: "Task 2", Value: "30" }, { Phase: "Phase 2", Step: "Step 2", Task:

问题 I have researched this and know I'm not the first to ask but I can't seem to get my head around it. I have created a simple example that I think will help me crack it if someone can provide the missing link! I have a table of areas that contains continents and countries in a hierarchy. I also have a table of places that contains cities and landmarks in a hierarchy. This table contains an area id column to join to the areas table. create table areas ( id NUMBER not null, name VARCHAR2(200) not

问题 I was playing around (out of interest) with retrieving a tree of nodes in a simple adjacency list with a recursive query using local variables. The solution i have so far is fun but i wonder (and this is my only question) why MySQL refuses to use any INDEX to optimize this query. Shouldn't MySQL be able to lookup the nearest child(s) by using an INDEX ? I'm curious why MySQL doesn't. Even when i use FORCE INDEX the execution plan doesn't change. This is the query so far, with 5 being the ID

问题 Disclaimer: I've been fighting against this problem since 2 days (I've read a lot of similar questions on SO).. so be patient, I'm missing something about the Group By with Linq and asking for help. The Class Structure Populating the sample data I have a list of Macrotab . Each Macrotab object contains a list of Tab . Each Tab object inside with Slot inside. List<MacroTab> hierarchaldata = CreateHierarchaldata(); *For keeping the question easy to read I've moved the CreateHierarchaldata,

问题 I am trying to traverse this XML data full of parent->child relationships and need a way to build a tree. Any help will be really appreciated. Also, in this case, is it better to have attributes or nodes for the parent-->child relationship? <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <nodes> <node name="Car" child="Engine"/> <node name="Car" child="Wheel"/> <node name="Engine" child="Piston"/> <node name="Engine" child="Carb"/> <node name="Carb" child="Bolt"/> <node name="Spare