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  • How can I modify my classes to use it's collections in WPF TreeView

    - by Victor
    Hello, i'am trying to modify my objects to make hierarchical collection model. I need help. My objects are Good and GoodCategory: public class Good { int _ID; int _GoodCategory; string _GoodtName; public int ID { get { return _ID; } } public int GoodCategory { get { return _GoodCategory; } set { _GoodCategory = value; } } public string GoodName { get { return _GoodName; } set { _GoodName = value; } } public Good(IDataRecord record) { _ID = (int)record["ID"]; _GoodtCategory = (int)record["GoodCategory"]; } } public class GoodCategory { int _ID; string _CategoryName; public int ID { get { return _ID; } } public string CategoryName { get { return _CategoryName; } set { _CategoryName = value; } } public GoodCategory(IDataRecord record) { _ID = (int)record["ID"]; _CategoryName = (string)record["CategoryName"]; } } And I have two Collections of these objects: public class GoodsList : ObservableCollection<Good> { public GoodsList() { string goodQuery = @"SELECT `ID`, `ProductCategory`, `ProductName`, `ProductFullName` FROM `products`;"; using (MySqlConnection conn = ConnectToDatabase.OpenDatabase()) { if (conn != null) { MySqlCommand cmd = conn.CreateCommand(); cmd.CommandText = productQuery; MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Add(new Good(rdr)); } } } } } public class GoodCategoryList : ObservableCollection<GoodCategory> { public GoodCategoryList () { string goodQuery = @"SELECT `ID`, `CategoryName` FROM `product_categoryes`;"; using (MySqlConnection conn = ConnectToDatabase.OpenDatabase()) { if (conn != null) { MySqlCommand cmd = conn.CreateCommand(); cmd.CommandText = productQuery; MySqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Add(new GoodCategory(rdr)); } } } } } So I have two collections which takes data from the database. But I want to use thats collections in the WPF TreeView with HierarchicalDataTemplate. I saw many post's with examples of Hierarlichal Objects, but I steel don't know how to make my objects hierarchicaly. Please help.

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  • Generate dynamic UPDATE command from Expression<Func<T, T>>

    - by Rui Jarimba
    I'm trying to generate an UPDATE command based on Expression trees (for a batch update). Assuming the following UPDATE command: UPDATE Product SET ProductTypeId = 123, ProcessAttempts = ProcessAttempts + 1 For an expression like this: Expression<Func<Product, Product>> updateExpression = entity => new Product() { ProductTypeId = 123, ProcessAttempts = entity.ProcessAttempts + 1 }; How can I generate the SET part of the command? SET ProductTypeId = 123, ProcessAttempts = ProcessAttempts + 1

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  • Real world examples of tree structures

    - by Arec Barrwin
    I'm looking for some examples of tree structures that are used in commercial/free software projects, modern or old. I can see examples on wikipedia, but I am looking for more concrete examples and how they're used. For example primary keys in databases are (from what I've read) stored in BST structure or a variation of the BST (feel free to correct me on this) My question isn't limited Binary Search Trees (BSTs), it can include any variation such as red-black, AVL and so on.

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  • Building a balanced binary search tree

    - by Znarkus
    Hi! Is there a method to build a balanced binary search tree? Example: 1 2 3 4 5 6 7 8 9 5 / \ 3 etc / \ 2 4 / 1 I'm thinking there is a method to do this, without using the more complex self-balancing trees. Otherwise I can do it on my own, but someone probably have done this already :)

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  • How to prepare for a programming competition? Graphs, Stacks, Trees, oh my! [closed]

    - by Simucal
    Last semester I attended ACM's (Association for Computing Machinery) bi-annual programming competition at a local University. My University sent 2 teams of 3 people and we competed amongst other schools in the mid-west. We got our butts kicked. You are given a packet with about 11 problems (1 problem per page) and you have 4 hours to solve as many as you can. They'll run your program you submit against a set of data and your output must match theirs exactly. In fact, the judging is automated for the most part. In any case.. I went there fairly confident in my programming skills and I left there feeling drained and weak. It was a terribly humbling experience. In 4 hours my team of 3 people completed only one of the problems. The top team completed 4 of them and took 1st place. The problems they asked were like no problems I have ever had to answer before. I later learned that in order to solve them some of them effectively you have to use graphs/graph algorithms, trees, stacks. Some of them were simply "greedy" algo's. My question is, how can I better prepare for this semesters programming competition so I don't leave there feeling like a complete moron? What tips do you have for me to be able to answer these problems that involve graphs, trees, various "well known" algorithms? How can I easily identify the algorithm we should implement for a given problem? I have yet to take Algorithm Design in school so I just feel a little out of my element. Here are some examples of the questions asked at the competitions: ACM Problem Sets Update: Just wanted to update this since the latest competition is over. My team placed 1st for our small region (about 6-7 universities with between 1-5 teams each school) and ~15th for the midwest! So, it is a marked improvement over last years performance for sure. We also had no graduate students on our team and after reviewing the rules we found out that many teams had several! So, that would be a pretty big advantage in my own opinion. Problems this semester ranged from about 1-2 "easy" problems (ie bit manipulation, string manipulation) to hard (graph problems involving fairly complex math and network flow problems). We were able to solve 4 problems in our 5 hours. Just wanted to thank everyone for the resources they provided here, we used them for our weekly team practices and it definitely helped! Some quick tips that I have that aren't suggested below: When you are seated at your computer before the competition starts, quickly type out various data structures that you might need that you won't have access to in your languages libraries. I typed out a Graph data-structure complete with floyd-warshall and dijkstra's algorithm before the competition began. We ended up using it in our 2nd problem that we solved and this is the main reason why we solved this problem before anyone else in the midwest. We had it ready to go from the beginning. Similarly, type out the code to read in a file since this will be required for every problem. Save this answer "template" someplace so you can quickly copy/paste it to your IDE at the beginning of each problem. There are no rules on programming anything before the competition starts so get any boilerplate code out the way. We found it useful to have one person who is on permanent whiteboard duty. This is usually the person who is best at math and at working out solutions to get a head start on future problems you will be doing. One person is on permanent programming duty. Your fastest/most skilled "programmer" (most familiar with the language). This will save debugging time also. The last person has several roles between assessing the packet of problems for the next "easiest" problem, helping the person on the whiteboard work out solutions and helping the person programming work out bugs/issues. This person needs to be flexible and be able to switch between roles easily.

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  • Best Data Structure For Time Series Data

    - by TriParkinson
    Hi all, I wonder if someone could take a minute out of their day to give their two cents on my problem. I would like some suggestions on what would be the best data structure for representing, on disk, a large data set of time series data. The main priority is speed of insertion, with other priorities in decreasing order; speed of retrieval, size on disk, size in memory, speed of removal. I have seen that B+ trees are often used in database because of their fast search times, but how about for fast insertion times? Is a linked list really the way to go? Thanks in advance for your time, Tri

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  • UVa #112 Tree Summing

    - by unclerojelio
    I'm working on UVa #112 Tree Summing. I have what I think should be a working solution but it is not accepted by the online judge due to a basic misunderstanding of the problem on my part. Consider the following inputs: -1 (-1()()) 77 (77(1()())()) or diagrammatically, the trees look like: -1 77 / \ / \ () () 1 () / \ () () According to at least two working solutions, the correct output for the above inputs is: yes no However, I don't understand why the second one should be 'no'. It looks to me like the rightmost path of the tree should give the proper sum. What am I missing?

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  • Calculating depth and descendants of tree

    - by yuudachi
    Can you guys help me with the algorithm to do these things? I have preorder, inorder, and postorder implemented, and I am given the hint to traverse the tree with one of these orders. I am using dotty to label (or "visit") the nodes. Depth is the number of edges from the root to the bottom leaf, so everytime I move, I add +1 to the depth? Something like that? No idea about the algorithm for descendants. They are asking about the number of nodes a specific node has under itself. These are normal trees btw.

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  • Tree + Recursion..

    - by RBA
    Hi.. I came across an article on Binary Trees Search . It uses intensive Recursive Algorithms.. I am just so confused with these stuff.. Please guide my path so as I understand these problems at ease, or any good website to read about recursion first and then solving these problems.. Please share your experience on it.. Its very urgent, and I want to learn these concepts as soon as possible.. Thankss... Regards.

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  • How to create and Expression tree to do the same as "StartsWith"

    - by Jonathan
    Hi to all. Currently, I have this method to compare two numbers Private Function ETForGreaterThan(ByVal query As IQueryable(Of T), ByVal propertyValue As Object, ByVal propertyInfo As PropertyInfo) As IQueryable(Of T) Dim e As ParameterExpression = Expression.Parameter(GetType(T), "e") Dim m As MemberExpression = Expression.MakeMemberAccess(e, propertyInfo) Dim c As ConstantExpression = Expression.Constant(propertyValue, propertyValue.GetType()) Dim b As BinaryExpression = Expression.GreaterThan(m, c) Dim lambda As Expression(Of Func(Of T, Boolean)) = Expression.Lambda(Of Func(Of T, Boolean))(b, e) Return query.Where(lambda) End Function It works fine and is consumed in this way query = ETForGreaterThan(query, Value, propertyInfo) As you can see, I give it an IQueryable collection and it add a where clause to it, base on a property and a value. Y can construct Lessthan, LessOrEqualThan etc equivalents as Expression has this operators predefined. ¿How can I transform this code to do the same with strings? Expression don't give me a predefined operator like "contains" or "startwith" and I'm really noob with Expression trees. Thanks, and please Post your answer in C#/VB. Choose the one that make you feel more confortable.

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  • Ruby GraphViz Binary Tree Record

    - by Jason M
    I'm using the ruby-graphviz gem and I'm trying to draw binary trees. I'd like to use the record shape so that each node can have a left, middle, and right field and, thus, if there are two edges leaving a node, the left and right edges can be distinguished. I tried specifying the field by concatenating the field name like this: @node1.name + ":left" But that did not work. What is the correct way of specifying the field? require 'rubygems' require 'graphviz' @graph = GraphViz.new( :G, :type => :digraph ) @node1 = @graph.add_node("1", "shape" => "record", "label" => "<left>|<f1> 1|<right>" ) @node2 = @graph.add_node("2", "shape" => "record", "label" => "<left>|<f1> 2|<right>" ) @graph.add_edge(@node1.name + ":left", @node2) # generate a random filename filename = "/tmp/#{(0...8).map{65.+(rand(25)).chr}.join}.png" @graph.output( :png => filename ) exec "open #{filename}"

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  • Dynamic expression tree how to

    - by Savvas Sopiadis
    Hello everybody! Implemented a generic repository with several Methods. One of those is this: public IEnumerable<T> Find(Expression<Func<T, bool>> where) { return _objectSet.Where(where); } Given to be it is easy to call this like this: Expression<Func<Culture, bool>> whereClause = c => c.CultureId > 4 ; return cultureRepository.Find(whereClause).AsQueryable(); But now i see (realize) that this kind of quering is "limiting only to one criteria". What i would like to do is this: in the above example c is of type Culture. Culture has several properties like CultureId, Name, Displayname,... How would i express the following: CultureId 4 and Name.contains('de') and in another execution Name.contains('us') and Displayname.contains('ca') and .... Those queries should be created dynamically. I had a look in Expression trees (as i thought this to be a solution to my problem - btw i never used them before) but i cannot find anything which points to my requirement. How can this be costructed? Thanks in advance

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  • Algorithm to Render a Horizontal Binary-ish Tree in Text/ASCII form

    - by Justin L.
    It's a pretty normal binary tree, except for the fact that one of the nodes may be empty. I'd like to find a way to output it in a horizontal way (that is, the root node is on the left and expands to the right). I've had some experience expanding trees vertically (root node at the top, expanding downwards), but I'm not sure where to start, in this case. Preferably, it would follow these couple of rules: If a node has only one child, it can be skipped as redundant (an "end node", with no children, is always displayed) All nodes of the same depth must be aligned vertically; all nodes must be to the right of all less-deep nodes and to the left of all deeper nodes. Nodes have a string representation which includes their depth. Each "end node" has its own unique line; that is, the number of lines is the number of end nodes in the tree, and when an end node is on a line, there may be nothing else on that line after that end node. As a consequence of the last rule, the root node should be in either the top left or the bottom left corner; top left is preferred. For example, this is a valid tree, with six end nodes (node is represented by a name, and its depth): [a0]------------[b3]------[c5]------[d8] \ \ \----------[e9] \ \----[f5] \--[g1]--------[h4]------[i6] \ \--------------------[j10] \-[k3] Which represents the horizontal, explicit binary tree: 0 a / \ 1 g * / \ \ 2 * * * / \ \ 3 k * b / / \ 4 h * * / \ \ \ 5 * * f c / \ / \ 6 * i * * / / \ 7 * * * / / \ 8 * * d / / 9 * e / 10 j (branches folded for compactness; * representing redundant, one-child nodes; note that *'s are actual nodes, storing one child each, just with names omitted here for presentation sake) (also, to clarify, I'd like to generate the first, horizontal tree; not this vertical tree) I say language-agnostic because I'm just looking for an algorithm; I say ruby because I'm eventually going to have to implement it in ruby anyway. Assume that each Node data structure stores only its id, a left node, and a right node. A master Tree class keeps tracks of all nodes and has adequate algorithms to find: A node's nth ancestor A node's nth descendant The generation of a node The lowest common ancestor of two given nodes Anyone have any ideas of where I could start? Should I go for the recursive approach? Iterative?

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  • Designing a hierarchical structure with lots of reads and writes?

    - by JD01
    I am in the process of working on a video on demand system part of it involves the management of a hierarchical tree structure (think windows explorer) which allows users to upload videos, move folders around, create new folders etc. User action will be allowed depending on which permissions they have. In addition to managing the structure (creating folders and uploading videos), subscribers will be viewing content (read access). The number of reads will be significantly more than the writes. My question (and it is big one) is should I store the data in a database (for the writes) and also have some sort of cache which will be used for the reads? or do I use two databases? or is there a better solution? Also I will have to resolve concurrency issues which I think optimistic locking on the database will resolve. I have a fair bit about CQRS over the last few months but not sure if this is the way to go. Any ideas?

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  • How to avoid circular relationship in SQL-Server?

    - by Shimmy
    I am creating a self-related table: Table Item columns: ItemId int - PK; Amount money - not null; Price money - a computed column using a UDF that retrieves value according to the items ancestors' Amount. ParentItemId int - nullable, reference to another ItemId in this table. I need to avoid a loop, meaning, a sibling cannot become an ancestor of his ancestors, meaning, if ItemId=2 ParentItemId = 1, then ItemId 1 ParentItemId = 2 shouldn't be allowed. I don't know what should be the best practice in this situation. I think I should add a CK that gets a Scalar value from a UDF or whatever else. EDIT: Another option is to create an INSTEAD OF trigger and put in 1 transaction the update of the ParentItemId field and selecting the Price field from the @@RowIdentity, if it fails cancel transaction, but I would prefer a UDF validating. Any ideas are sincerely welcomed.

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  • SugarCRM - how to make users see only child users?

    - by John
    Hello, I want to change the behaviour of Sugar CRM community version. Here's what sugar currently does: 1) Admin logs into Sugar. 2) Admin clicks on Admin tab. 3) Admin creates a new user named George with admin access 4) Under user information section, Admin makes George report to Admin (in the database, it will show users.report_to_id is the admin's user_id) 5) Admin saves and logs out 6) George logs in with his password 7) George goes to admin tab. 8) George goes to list users page and sees all users, including Admin, the person he is supposed to report to. I want to change step 8 such that George is not allowed to see the user he reports to. Additionally, he is not allowed to see his grand parent user, great grand parent user, great great grand parent user etc... George should only be able to see users that he creates. How can I achieve this? Is this even possible?

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  • IHierarchyData and IHierarchicalEnumerable in Winforms

    - by Jonathan
    Hi! Currently,I know how to do a lazy implementation of the loading procedure of the nodes in a treeview control, and read the related questions in stackoverflow, but I'm also reading about IHierarchyData and IHierarchicalEnumerable interfaces in asp.net (I didn't know to code asp.net) that allow to bind a collection to a treeview in order to display the items automatically. It would like to know if I can do the same in winforms and C#. I think that the interfaces previous mentioned are not available in winforms. Thanks.

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  • SQL Server 2005 database design - many-to-many relationships with hierarchy

    - by Remnant
    Note I have completely re-written my original post to better explain the issue I am trying to understand. I have tried to generalise the problem as much as possible. Also, my thanks to the original people who responded. Hopefully this post makes things a little clearer. Context In short, I am struggling to understand the best way to design a small scale database to handle (what I perceive to be) multiple many-to-many relationships. Imagine the following scenario for a company organisational structure: Textile Division Marketing Division | | ---------------------- ---------------------- | | | | HR Dept Finance Dept HR Dept Finance Dept | | | | ---------- ---------- ---------- --------- | | | | | | | | Payroll Hiring Audit Tax Payroll Hiring Audit Accounts | | | | | | | | Emps Emps Emps Emps Emps Emps Emps Emps NB: Emps denotes a list of employess that work in that area When I first started with this issue I made four separate tables: Divisions - Textile, Marketing (PK = DivisionID) Departments - HR, Finance (PK = DeptID) Functions - Payroll, Hiring, Audit, Tax, Accounts (PK = FunctionID) Employees - List of all Employees (PK = EmployeeID) The problem as I see it is that there are multiple many-to-many relationships i.e. many departments have many divisions and many functions have many departments. Question Giving the database structure above, suppose I wanted to do the following: Get all employees who work in the Payroll function of the Marketing Division To do this I need to be able to differentiate between the two Payroll departments but I am not sure how this can be done? I understand that I could build a 'Link / Junction' table between Departments and Functions so that I can retrieve which Functions are in which Departments. However, I would still need to differentiate the Division they belong to. Research Effort As you can see I am an abecedarian when it comes to database deisgn. I have spent the last two days resaerching this issue, traversing nested set models, adjacency models, reading that this issue is known not to be NP complete etc. I am sure there is a simple solution?

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  • Algorithm for parsing a flat tree into a non-flat tree

    - by Chad Johnson
    I have the following flat tree: id name parent_id is_directory =========================================================== 50 app 0 1 31 controllers 50 1 11 application_controller.rb 31 0 46 models 50 1 12 test_controller.rb 31 0 31 test.rb 46 0 and I am trying to figure out an algorithm for getting this into the following tree structuree: [{ id: 50, name: app, is_directory: true children: [{ id: 31, name: controllers, is_directory: true, children: [{ id: 11, name: application_controller.rb is_directory: false },{ id: 12, name: test_controller.rb, is_directory: false }], },{ id: 46, name: models, is_directory: true, children: [{ id: 31, name: test.rb, is_directory: false }] }] }] Can someone point me in the right direction? I'm looking for steps (eg. build an associative array; loop through the array looking for x; etc.).

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  • PHP Doctrine: Custom nested set?

    - by ropstah
    Is it possible to have nested set capabilities in this somewhat custom setup? Consider these 4 tables: Object: (oid, name) contains: [1, 'Licence'] and [2, 'Exemption'] Licence: (lid, name) Exemption: (eid, name) Cost: (oid, oid_ref, cost_oid, cost_oid_ref) For: P = Licence with lid [1] R = Exemption with eid [2] i can say "object P is a parent to object R" if the following Cost record exists: [oid: 2 oid_ref: 2 cost_oid: 1 cost_oid_ref: 1] I understand that this creates somesort of 'conditional foreign key' relation which I need to define in code. Is it possible to have the nested set loaded with these conditions?

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