hierarchical-data

问题 I have to store a tree in a database, so what is the best way to do this? Show the method you use and name its pros and cons. (I am using SQL Server 2005) 回答1: I found the discussion in the SQL Anti-patterns very helpfull, as it also focuses on the drawbacks of every implementation. Also, The slides 48-77 in this presentation reiterate that analisys. Bottom line, there is no such thing as a generic tree, and no silver bullet for SQL trees. You'll have to ask yourself about the data, how and

问题 I have to store a tree in a database, so what is the best way to do this? Show the method you use and name its pros and cons. (I am using SQL Server 2005) 回答1: I found the discussion in the SQL Anti-patterns very helpfull, as it also focuses on the drawbacks of every implementation. Also, The slides 48-77 in this presentation reiterate that analisys. Bottom line, there is no such thing as a generic tree, and no silver bullet for SQL trees. You'll have to ask yourself about the data, how and

问题 I'm working with mySQL, and I'm in a situation where I need to select data from one table that matches an ID at any level in parent -> child data hierarchy in the other table. Further more, I would like to resolve this with a well written SQL query, rather than a recursive function in my PHP code, as this feature will be used quite a bit. I did try searching, and I have stumbled upon numerous similar problems (most of them being resolved), however none of them helped me. To help illustrate

问题 I am not totally sure I am naming this right, but please bear with me. I am wondering if is possible to do something like this in SQL(MySQL specifically): Let's say we have tree-like data that is persisted in the database in the following table: mysql> desc data_table; +------------------------+---------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------------------+---------------------+------+-----+---------+----------------+ |

问题 I'm evaluating the Backbone javascript framework for use in a project that will display a hierarchical model in a tree view widget (think the Windows file browser). I love how Backbone thinks about the world. However, there's a lot of coding involved before I get to a proof of concept that has Backbone actually receiving a hierarchical model from a server and updating a tree widget. I've seen there's various solutions for representing deep data structures with Backbone, but I'm wondering...

问题 I have an exported table from my accounting software like below in SQL Server 2008. AccountID AccountName SourceCast --------- ----------- ----------- 11 Acc11 9401 12 Acc12 9401 13 Acc13 9401 11/11 Acc11/11 9401 11/12 Acc11/12 9401 11/111 Acc11/111 9401 11/11/001 Acc11/11/001 9401 11/11/002 Acc11/11/002 9401 15 Acc15 9402 12 Acc12 9402 13 Acc13 9402 15/15 Acc15/15 9402 15/12 Acc15/12 9402 15/111 Acc15/111 9402 15/15/001 Acc15/15/001 9402 15/15/002 Acc15/15/002 9402 Then expected result must

问题 I have 2 tables Categories id - name - parent 1 - Category A - 0 2 - Category B - 0 3 - Category C - 0 4 - Category D - 0 5 - Subcategory Of 1 - 1 6 - Subcategory Of 5 - 5 7 - Subcategory Of 5 - 5 Product id - name - category - description 1 - Name - 5 - Description How to select all products and join main category through sub-categories? Product categories can has only 1 or 2 or 3 or 4 levels (Unknown level). I use "WITH RECURSIVE" in categories table but can't find the way to combine

问题 I have 2 tables Categories id - name - parent 1 - Category A - 0 2 - Category B - 0 3 - Category C - 0 4 - Category D - 0 5 - Subcategory Of 1 - 1 6 - Subcategory Of 5 - 5 7 - Subcategory Of 5 - 5 Product id - name - category - description 1 - Name - 5 - Description How to select all products and join main category through sub-categories? Product categories can has only 1 or 2 or 3 or 4 levels (Unknown level). I use "WITH RECURSIVE" in categories table but can't find the way to combine

问题 I have a collection of class X instances that point to themselves (self-referencing). As an example, my class could look like this: public class X { string Name {get;set;} List<X> Children {get;} } Now lets say I have a list of instances of class X, which can self-reference themselves N levels down. My question is: How do get the instances of X from Nth level in my list? Basically I am trying to do in C# what a recursive self-referencing common table expression would do in SQL, which is to

问题 I'm trying to implement lazy loading on ADG. and I'm stuck in the point where I need to add the returned children to the expanded node. Currently I'm doing: private function childrenloaded(data:*,item:*):void { var len:int = data.length; for(var i=0;i<len;i++) (internalMainGrid.dataProvider as HierarchicalCollectionView).addChild(item, data[i]); } This works fine, but it is slow. (21,990 ms for total: 919 records) is there some way I can speed this up? - like setting children directly Ex: var