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  • Should all foreign table references use foreign key constraints

    - by TecBrat
    Closely related to: Foreign key restrictions -> yes or no? I asked a question on SO and it led me to ask this here. If I'm faced with a choice of having a circular reference or just not enforcing the restraint, which is the better choice? In my particular case I have customers and addresses. I want an address to have a reference to a customer and I want each customer to have a default billing address id and a default shipping address id. I might query for all addresses that have a certain customer ID or I might query for the address with the ID that matches the default shipping or billing address ids. I'm not sure yet how the constraints (or lack of) will effect the system as my application and it's data age.

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  • How do I use Sketchflow sample data for a ListBoxItem Template at design time?

    - by Boris Nikolaevich
    I am using Expression Blend 4 and Visual Studio 2010 to create a Sketchflow prototype. I have a Sample Data collection and a ListBox that is bound to it. This displays as I would expect both at design time and at run time. However, the ListBoxItem template it just complex enough that I wanted to pull it out into its own XAML file. Even though the items still render as expected in the main ListBox where the template is used, when I open the template itself, all of the databound controls are empty. If I add a DataContext to the template, I can see and work with the populated objects while in the template, but then that local DataContext overrides the DataContext set on the listbox. A bit of code will illustrate. Start by creating a Sketchflow project (I am using Silverlight, but it should work the same for WPF), then add a project data source called SampleDataSource. Add a collection called ListData, with a single String property called Title. Here is the (scaled down) code for the main Sketchflow screen, which we'll call Main.xaml: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:DemoScreens" mc:Ignorable="d" x:Class="DemoScreens.Main" Width="800" Height="600"> <UserControl.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="ProjectDataSources.xaml"/> </ResourceDictionary.MergedDictionaries> <DataTemplate x:Key="ListBoxItemTemplate"> <local:DemoListBoxItemTemplate d:IsPrototypingComposition="True" Margin="0,0,5,0" Width="748"/> </DataTemplate> </ResourceDictionary> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="#5c87b2" DataContext="{Binding Source={StaticResource SampleDataSource}}"> <ListBox Background="White" x:Name="DemoList" Style="{StaticResource ListBox-Sketch}" Margin="20,100,20,20" ItemTemplate="{StaticResource ListBoxItemTemplate}" ItemsSource="{Binding ListData}" ScrollViewer.HorizontalScrollBarVisibility="Disabled"/> </Grid> </UserControl> You can see that it references the DemoListBoxItemTemplate, which is defined in its own DemoListBoxItemTemplate.xaml: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:DemoScreens" mc:Ignorable="d" x:Class="DemoScreens.DemoListBoxItemTemplate"> <Grid x:Name="LayoutRoot"> <TextBlock Text="{Binding Title}" Style="{StaticResource BasicTextBlock-Sketch}" Width="150"/> </Grid> </UserControl> Obviously, this is way simpler than my actual listbox, but it should be enough to illustrate my problem. When you open Main.xaml in the Expression designer, the list box is populated with sample data. But when you open DemoListBoxItemTemplate.xaml, there is no data context and therefore no data to display—which makes it more difficult to identify controls visually. How can I have sample data displayed when I am working with the template, while still allowing the larger set of sample data to be used for the ListBox itself?

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  • Are there any decent free JAVA data plotting libraries out there?

    - by Kurt W. Leucht
    On a recent JAVA project, we needed a free JAVA based real-time data plotting utility. After much searching, we found this tool called the Scientific Graphics Toolkit or SGT from NOAA. It seemed pretty robust, but we found out that it wasn't terribly configurable. Or at least not configurable enough to meet our needs. We ended up digging very deeply into the JAVA code and reverse engineering the code and changing it all around to make the plot tool look and act the way we wanted it to look and act. Of course, this killed any chance for future upgrades from NOAA. So what free or cheap JAVA based data plotting tools or libraries do you use? Followup: Thanks for the JFreeChart suggestions. I checked out their website and it looks like a very nice data charting and plotting utility. I should have made it clear in my original question that I was looking specifically to plot real-time data. I corrected my question above to make that point clear. It appears that JFreeChart support for live data is marginal at best, though. Any other suggestions out there?

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  • Google Federated Login vs Hybrid Protocol vs Google Data Authentication. Whats's the Difference?

    - by johnfelix
    Hi, I am trying to implement Google Authentication in my website, in which I would also be pulling some Google Data using the Google Data API and I am using Google App Engine with Jinja2. My question is, so many ways are mentioned to do it. I am confused between Google Federated Login,Google Data Protocol, Hybrid Protocol. Are these things the same or different ways to do the same thing. From what I read and understood, which might be incorrect, Google Federated Login uses the hybrid protocol to authenticate and fetch the google data. Is there a proper guide to implement any one of these in python. Examples which I found at the google link are kind of different. From what I understood,correct me if i am wrong, I have to implement only the OpenID Consumer part. In order to implement Google Federated Login in Python, I saw that we need to download a separate library from the openid-enabled.com but I found a different library for the google data implementation at http://code.google.com/p/gdata-python-client/ As you can see, I am confused a lot :D. Please help me :) Thanks

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  • How to use JQUERY to filter table rows dynamically using multiple form inputs

    - by tresstylez
    I'm displaying a table with multiple rows and columns. I'm using a JQUERY plugin called uiTableFilter which uses a text field input and filters (shows/hides) the table rows based on the input you provide. All you do is specify a column you want to filter on, and it will display only rows that have the text field input in that column. Simple and works fine. I want to add a SECOND text input field that will help me narrow the results down even further. So, for instance if I had a PETS table and one column was petType and one was petColor -- I could type in CAT into the first text field, to show ALL cats, and then in the 2nd text field, I could type black, and the resulting table would display only rows where BLACK CATS were found. Basically, a subset. Here is the JQUERY I'm using: $("#typeFilter").live('keyup', function() { if ($(this).val().length > 2 || $(this).val().length == 0) { var newTable = $('#pets'); $.uiTableFilter( theTable, this.value, "petType" ); } }) // end typefilter $("#colorFilter").live('keyup', function() { if ($(this).val().length > 2 || $(this).val().length == 0) { var newTable = $('#pets'); $.uiTableFilter( newTable, this.value, "petColor" ); } }) // end colorfilter Problem is, I can use one filter, and it will display the correct subset of table rows, but when I provide input for the other filter, it doesn't seem to recognize the visible table rows that are remaining from the previous column, but instead it appears that it does an entirely new filtering of the original table. If 10 rows are returned after applying one filter, the 2nd filter should only apply to THOSE 10 rows. I've tried LIVE and BIND, but not working. Can anyone shed some light on where I'm going wrong? Thanks!

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  • ASP.NET: Custom MembershipProvider with a custom user table

    - by blahblah
    I've recently started tinkering with ASP.NET MVC, but this question should apply to classic ASP.NET as well. For what it's worth, I don't know very much about forms authentication and membership providers either. I'm trying to write my own MembershipProvider which will be connected to my own custom user table in my database. My user table contains all of the basic user information such as usernames, passwords, password salts, e-mail addresses and so on, but also information such as first name, last name and country of residence. As far as I understand, the standard way of doing this in ASP.NET is to create a user table without the extra information and then a "profile" table with the extra information. However, this doesn't sound very good to me, because whenever I need to access that extra information I would have to make one extra database query to get it. I read in the book "Pro ASP.NET 3.5 in C# 2008" that having a separate table for the profiles is not a very good idea if you need to access the profile table a lot and have many different pages in your website. Now for the problem at hand... As I said, I'm writing my own custom MembershipProvider subclass and it's going pretty well so far, but now I've come to realize that the CreateUser doesn't allow me to create users in the way I'd like. The method only takes a fixed number of arguments and first name, last name and country of residence are not part of them. So how would I create an entry for the new user in my custom table without this information at hand in CreateUser of my MembershipProvider?

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  • How to efficiently save changes made in UI/main thread with Core Data?

    - by Jaanus
    So, there have been several posts here about importing and saving data from an external data source into Core Data. Apple documents a reasonable pattern for this: "import and save on background thread, merge saved objects to main thread." All fine and good. I have a related but different problem: the user is modifying data in the UI and main thread, and thus modifies state of some objects in the managed object context (MOC). I would like to save these changes from time to time. What is a good way to do that? Now, you could say that I could do the same: create a background thread with its own MOC and pass the changed objectID-s there. The catch-22 for me with this is that an object's ID changes when it is saved, and I cannot guarantee the order of things happening. I may end up passing a different objectID into the background thread for the same object, based on whether the object has been previously saved or not, and I don't know if Core Data can resolve this and see that different objectID-s are pointing to the same object and not create duplicates for me. (I could test this, but I'm lazywebbing with this question first.) One thought I had: I could always do MOC saves on a background thread, and queue them up with operationqueue, so that there is always only one save in progress. I would not create a new MOC, I would just use the same MOC as in main thread. Now, this is not thread safe and when someone modifies the MOC in main thread while it is being saved in background thread, the results will probably be catastrophic. But, minus the thread safety, you can see what kind of solution I'd wish for. To be clear, the problem I need to fix is that if I just do the save in main thread, it blocks the UI for an unacceptably long period of time, I want to move the save to background thread. So, questions: what about the reasoning of an object ID changing during saving, and Core Data being able to resolve them to the same object? Would this be the right way of addressing this problem? any other good ways of doing this?

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  • Create a HTML table from nested maps (and vectors)

    - by Kenny164
    I'm trying to create a table (a work schedule) I have coded previously using python, I think it would be a nice introduction to the Clojure language for me. I have very little experience in Clojure (or lisp in that matter) and I've done my rounds in google and a good bit of trial and error but can't seem to get my head around this style of coding. Here is my sample data (will be coming from an sqlite database in the future): (def smpl2 (ref {"Salaried" [{"John Doe" ["12:00-20:00" nil nil nil "11:00-19:00"]} {"Mary Jane" [nil "12:00-20:00" nil nil nil "11:00-19:00"]}] "Shift Manager" [{"Peter Simpson" ["12:00-20:00" nil nil nil "11:00-19:00"]} {"Joe Jones" [nil "12:00-20:00" nil nil nil "11:00-19:00"]}] "Other" [{"Super Man" ["07:00-16:00" "07:00-16:00" "07:00-16:00" "07:00-16:00" "07:00-16:00"]}]})) I was trying to step through this originally using for then moving onto doseq and finally domap (which seems more successful) and dumping the contents into a html table (my original python program outputed this from a sqlite database into an excel spreadsheet using COM). Here is my attempt (the create-table fn): (defn html-doc [title & body] (html (doctype "xhtml/transitional") [:html [:head [:title title]] [:body body]])) (defn create-table [] [:h1 "Schedule"] [:hr] [:table (:style "border: 0; width: 90%") [:th "Name"][:th "Mon"][:th "Tue"][:th "Wed"] [:th "Thur"][:th "Fri"][:th "Sat"][:th "Sun"] [:tr (domap [ct @smpl2] [:tr [:td (key ct)] (domap [cl (val ct)] (domap [c cl] [:tr [:td (key c)]]))]) ]]) (defroutes tstr (GET "/" ((html-doc "Sample" create-table))) (ANY "*" 404)) That outputs the table with the sections (salaried, manager, etc) and the names in the sections, I just feel like I'm abusing the domap by nesting it too many times as I'll probably need to add more domaps just to get the shift times in their proper columns and the code is getting a 'dirty' feel to it. I apologize in advance if I'm not including enough information, I don't normally ask for help on coding, also this is my 1st SO question :). If you know any better approaches to do this or even tips or tricks I should know as a newbie, they are definitely welcome. Thanks.

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  • Binary Search Tree Implementation

    - by Gabe
    I've searched the forum, and tried to implement the code in the threads I found. But I've been working on this real simple program since about 10am, and can't solve the seg. faults for the life of me. Any ideas on what I'm doing wrong would be greatly appreciated. BST.h (All the implementation problems should be in here.) #ifndef BST_H_ #define BST_H_ #include <stdexcept> #include <iostream> #include "btnode.h" using namespace std; /* A class to represent a templated binary search tree. */ template <typename T> class BST { private: //pointer to the root node in the tree BTNode<T>* root; public: //default constructor to make an empty tree BST(); /* You have to document these 4 functions */ void insert(T value); bool search(const T& value) const; bool search(BTNode<T>* node, const T& value) const; void printInOrder() const; void remove(const T& value); //function to print out a visual representation //of the tree (not just print the tree's values //on a single line) void print() const; private: //recursive helper function for "print()" void print(BTNode<T>* node,int depth) const; }; /* Default constructor to make an empty tree */ template <typename T> BST<T>::BST() { root = NULL; } template <typename T> void BST<T>::insert(T value) { BTNode<T>* newNode = new BTNode<T>(value); cout << newNode->data; if(root == NULL) { root = newNode; return; } BTNode<T>* current = new BTNode<T>(NULL); current = root; current->data = root->data; while(true) { if(current->left == NULL && current->right == NULL) break; if(current->right != NULL && current->left != NULL) { if(newNode->data > current->data) current = current->right; else if(newNode->data < current->data) current = current->left; } else if(current->right != NULL && current->left == NULL) { if(newNode->data < current->data) break; else if(newNode->data > current->data) current = current->right; } else if(current->right == NULL && current->left != NULL) { if(newNode->data > current->data) break; else if(newNode->data < current->data) current = current->left; } } if(current->data > newNode->data) current->left = newNode; else current->right = newNode; return; } //public helper function template <typename T> bool BST<T>::search(const T& value) const { return(search(root,value)); //start at the root } //recursive function template <typename T> bool BST<T>::search(BTNode<T>* node, const T& value) const { if(node == NULL || node->data == value) return(node != NULL); //found or couldn't find value else if(value < node->data) return search(node->left,value); //search left subtree else return search(node->right,value); //search right subtree } template <typename T> void BST<T>::printInOrder() const { //print out the value's in the tree in order // //You may need to use this function as a helper //and create a second recursive function //(see "print()" for an example) } template <typename T> void BST<T>::remove(const T& value) { if(root == NULL) { cout << "Tree is empty. No removal. "<<endl; return; } if(!search(value)) { cout << "Value is not in the tree. No removal." << endl; return; } BTNode<T>* current; BTNode<T>* parent; current = root; parent->left = NULL; parent->right = NULL; cout << root->left << "LEFT " << root->right << "RIGHT " << endl; cout << root->data << " ROOT" << endl; cout << current->data << "CURRENT BEFORE" << endl; while(current != NULL) { cout << "INTkhkjhbljkhblkjhlk " << endl; if(current->data == value) break; else if(value > current->data) { parent = current; current = current->right; } else { parent = current; current = current->left; } } cout << current->data << "CURRENT AFTER" << endl; // 3 cases : //We're looking at a leaf node if(current->left == NULL && current->right == NULL) // It's a leaf { if(parent->left == current) parent->left = NULL; else parent->right = NULL; delete current; cout << "The value " << value << " was removed." << endl; return; } // Node with single child if((current->left == NULL && current->right != NULL) || (current->left != NULL && current->right == NULL)) { if(current->left == NULL && current->right != NULL) { if(parent->left == current) { parent->left = current->right; cout << "The value " << value << " was removed." << endl; delete current; } else { parent->right = current->right; cout << "The value " << value << " was removed." << endl; delete current; } } else // left child present, no right child { if(parent->left == current) { parent->left = current->left; cout << "The value " << value << " was removed." << endl; delete current; } else { parent->right = current->left; cout << "The value " << value << " was removed." << endl; delete current; } } return; } //Node with 2 children - Replace node with smallest value in right subtree. if (current->left != NULL && current->right != NULL) { BTNode<T>* check; check = current->right; if((check->left == NULL) && (check->right == NULL)) { current = check; delete check; current->right = NULL; cout << "The value " << value << " was removed." << endl; } else // right child has children { //if the node's right child has a left child; Move all the way down left to locate smallest element if((current->right)->left != NULL) { BTNode<T>* leftCurrent; BTNode<T>* leftParent; leftParent = current->right; leftCurrent = (current->right)->left; while(leftCurrent->left != NULL) { leftParent = leftCurrent; leftCurrent = leftCurrent->left; } current->data = leftCurrent->data; delete leftCurrent; leftParent->left = NULL; cout << "The value " << value << " was removed." << endl; } else { BTNode<T>* temp; temp = current->right; current->data = temp->data; current->right = temp->right; delete temp; cout << "The value " << value << " was removed." << endl; } } return; } } /* Print out the values in the tree and their relationships visually. Sample output: 22 18 15 10 9 5 3 1 */ template <typename T> void BST<T>::print() const { print(root,0); } template <typename T> void BST<T>::print(BTNode<T>* node,int depth) const { if(node == NULL) { std::cout << std::endl; return; } print(node->right,depth+1); for(int i=0; i < depth; i++) { std::cout << "\t"; } std::cout << node->data << std::endl; print(node->left,depth+1); } #endif main.cpp #include "bst.h" #include <iostream> using namespace std; int main() { BST<int> tree; cout << endl << "LAB #13 - BINARY SEARCH TREE PROGRAM" << endl; cout << "----------------------------------------------------------" << endl; // Insert. cout << endl << "INSERT TESTS" << endl; // No duplicates allowed. tree.insert(0); tree.insert(5); tree.insert(15); tree.insert(25); tree.insert(20); // Search. cout << endl << "SEARCH TESTS" << endl; int x = 0; int y = 1; if(tree.search(x)) cout << "The value " << x << " is on the tree." << endl; else cout << "The value " << x << " is NOT on the tree." << endl; if(tree.search(y)) cout << "The value " << y << " is on the tree." << endl; else cout << "The value " << y << " is NOT on the tree." << endl; // Removal. cout << endl << "REMOVAL TESTS" << endl; tree.remove(0); tree.remove(1); tree.remove(20); // Print. cout << endl << "PRINTED DIAGRAM OF BINARY SEARCH TREE" << endl; cout << "----------------------------------------------------------" << endl; tree.print(); cout << endl << "Program terminated. Goodbye." << endl << endl; } BTNode.h #ifndef BTNODE_H_ #define BTNODE_H_ #include <iostream> /* A class to represent a node in a binary search tree. */ template <typename T> class BTNode { public: //constructor BTNode(T d); //the node's data value T data; //pointer to the node's left child BTNode<T>* left; //pointer to the node's right child BTNode<T>* right; }; /* Simple constructor. Sets the data value of the BTNode to "d" and defaults its left and right child pointers to NULL. */ template <typename T> BTNode<T>::BTNode(T d) : left(NULL), right(NULL) { data = d; } #endif Thanks.

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  • Doing large updates against indexed view

    - by user217136
    We have an indexed view that runs across three large tables. Two of these tables (A & B) are constantly getting updated with user transactions and the other table (C) contains data product info that is needs to be updated once a week. This product table contains over 6 million records. We need this view across these three tables for our core business process and unfortunately we cannot change this aspect. We even had a sql server MVP come in to help test under load to make sure we have the most efficient configuration. There is one column in the product table that gets utilized in the view and has to be updated each week. The problem we are now encountering is that as volume is increasing on our transactions against tables A & B, the update to Table C is causing deadlocks. I have tried several different methods to no avail: 1) I was hoping that we could change the view so that table C could be a dirty read "WITH (NOLOCK)" but apparently that functionality is not available with indexes views. 2) I thought about updating a new column in Table C and then just renaming it when the process is done but you cannot do that due to the dependency in the view. 3) I also entertained the idea of writing this value to a temporary product table, and then running an ALTER statement against the view to have it point to my new table. however when i did that the indexes on my view were dropped and it took quite a bit of time to recreate them. 4) we tried to do the weekly update in small chunks (as small as 100 records at a time) but we still run into dead locks. questions: a) we are using sql server 2005. Does sql server 2008 have a new functionality with their indexed views that would help us? Is there now a way to do dirty reads w/ an indexed view? b) a better approach to altering an existing view to point to a new table? thanks!

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  • Core Data - How to check if a managed object's properties have been deallocated?

    - by georryan
    I've created a program that uses core data and it works beautifully. I've since attempted to move all my core data methods calls and fetch routines into a class that is self contained. My main program then instantiates that class and makes some basic method calls into that class, and the class then does all the core data stuff behind the scenes. What I'm running into, is that sometimes I'll find that when I grab a managed object from the context, I'll have a valid object, but its properties have been deallocated, and I'll cause a crash. I've played with the zombies and looked for memory leaks, and what I have gathered is it seems that the run loop is probably responsible for deallocating the memory, but I'm not sure. Is there a way to determine if that memory has been deallocated and force the core data to get it back if I need to access it? My managedObjectContext never gets deallocated, and the fetchedResultsController never does, either. I thought maybe I needed to use the [managedObjectContext refreshObject:mergeData:] method, or the [managedObjectContext setRetainsRegisteredObjects:] method. Although, I'm under the impression that last one may not be the best bet since it will be more memory intensive (from what I understand). These errors only popped up when I moved the core data calls into another class file, and they are random when they show up. Any insight would be appreciated. -Ryan

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  • Any chance to get Core Data using Tokyo Cabinet as the persistent store?

    - by dontWatchMyProfile
    I watched a free high quality video with Aaron Hillegass about Core Data vs Tokyo Cabinet. Besides that this guy is amazingly funny (really, if you want to laugh now, watch it!), he shows off Tokyo Cabinet beeing about 40x faster than Core Data. I wonder if it's worth thinking about how to attach this to Core Data? Does that make any sense? Maybe as a custom atomic store or something like this?

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  • How to Load Data from Text File in MySQL?

    - by Taz
    I have this file availableHere Fields are separated by space and newline starts at new line. I am using this command to load data mysql> LOAD DATA LOCAL INFILE 'C:\\Documents and Settings\\Scan\\My Documents\\Downloads\\images_en.nt\\Sample4.txt' INTO TABLE NER.Images FIELDS TERMINATED BY' ' LINES TERMINATED BY '\n';' Only one row is loaded and if I execute again No row is loaded. Where is the problem? Data can be modified to reformat if required.

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  • Adding line with text between pattern and next occurence of the same pattern in bash

    - by kasper
    I am writing a bash script that modifies a file that looks like this: --- usr1 --- data data data data data data data data data data data data --- usr2 --- data data data data data data data data --- usr3 --- data data data data --- endline --- One question is: How to add next user line --- usrn --- after last user data lines? Second one is: How to delete specific user data lines (data lines and --- userx ---) i.e. I would like to delete usr2 with all his data set. It must work on bash 2.05 :) and I think it will use awk or sed, but I'm not sure.

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  • Internet Explorer table 1 pixel spacing problem

    - by Dennis G.
    I've found a strange problem with Internet Explorer related to table spacing and cannot find a way to work around it. An empty table results in a single pixel white space with Internet Explorer (6 and 7, 8 not yet tested), while all other browsers ignore the empty table. Here's a picture of the problem: And here is the minimum HTML code to reproduce the issue (please note that there are more margin/padding css attributes and table attributes specified than really needed, I just tested if this fixes IE's behavior): <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <body> <div style="width: 200px; border: 1px black solid"> <table border="0" cellspacing="0" cellpadding="0" style="margin: 0pt; padding: 0pt; border-collapse: collapse;"> <tr> <td style="padding: 0; margin: 0"> </td> </tr> </table> <div style="background: red"> Test </div> </div> </body> </html> I'm not using an empty table as specified in the example above, but this was the minimum code that displays this behavior. Any ideas on how to fix this and remove the white space with IE?

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  • Resources to learn about engineering aspects of data analytics (OLAP, warehousing, ETL, etc.)

    - by JT
    I'm a math/stats guy, interested in learning more about the engineering aspects of "data analytics" (this may be an overly broad term, this is a case of "I don't know what I don't know", so I'm not sure how to be more specific). I'm fine with manipulating and analyzing the data once it's already stored somewhere and I can access it, and I'm fine with writing scripts and SQL queries (and have a general knowledge of things like normalization). What I don't know is the whole engineering process of capturing and storing the data. For example, terms I've heard thrown about that I only vaguely understand the meaning of include: - OLAP, OLTP - Data warehousing - ETL - ??? What's a good book (or any other resource) to learn about these kinds of things? What are things I should know about database design (normalization seems kinda "obvious" to me, something I would have done even before I knew the term -- is there anything else?)? In other words, for jobs falling under the umbrella term of "analytics engineer", what kinds of things should I know?

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  • Jquery problem - cant expand the row above in a table

    - by apg1985
    Hi People, What I cant figure out is how I would toggle a row in a table using the one below it. So say I have a table with 2 rows the first contains content and the one below contains a button, when the page loads the content row is hidden and when you click the button it toggles the content row on and off. In the example the first table works but the second does not, I need the second one to work. <!DOCTYPE HTML> <html> <head> <title>Testing Horizontal Accordion</title> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript"> $(document).ready(function() { $(".sectionhead").toggle( function() { $(this).next("tr").hide(); }, function() { $(this).next("tr").show(); } ) }); </script> </head> <body> <table> <tr class="sectionhead"><td></td></tr> <tr class="child"><td>child</td></tr> </table> <br> <table> <tr class="child"><td>child</td></tr> <tr class="sectionhead"><td></td></tr> </table> </body> </html>

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  • Designing DAL in .NET to be "data-source independent" and not just "database independent" ?

    - by Munish Goyal
    How to design such flexible DAL (specifically in .NET) ? What interfaces .NET provides and what should be done on my own ? Its a greenfield project starting with SQL Server as data source but in future, parts of it will move to different NoSQL type of datastores. Also, we may need to experiment with lot of different datastores (like some data may have to go with Cassandra, some with RDBMS, some to other DHT etc.) Therefore easily switchable access layer will be needed. All i know right now is the 'data' and 'operations needed on that data'.

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  • Finding the right terminology for a dictionary table

    - by Karl Forner
    My concern is about what I currently call "dictionary tables", that are database tables containing a list of controlled vocabulary. Let's use an example: Suppose you have a table User containing fields: user_id : primary key first_name last_name user_type_id : foreign key to the UserType table and another table UserType with just two fields: user_type_id : primary key name : the name/value of a particular type of user. For instance, the UserType table may contain (1, Administrator), (2, PowerUser), (3, Normal)... My question is: what is the canonical term for a table like UserType, that only contains a list of (dictinct) words. I want to publish some code that help managing this kind of tables, but first I have to name them ! Thanks for your help. Current state of thought: For now I feel Lookup Tables is a good term. It is also used with the same meaning in these posts: http://dbix-class.35028.n2.nabble.com/RFC-Component-for-Lookup-tables-td3504085.html http://tonyandrews.blogspot.de/2004/10/otlt-and-eav-two-big-design-mistakes.html Lookup Tables Best Practices: DB Tables... or Enumerations The only problem is that lookup table is also sometimes used to name a junction table.

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  • JCombobox containing enum values inside a table

    - by Edan
    Hello, I have a class containing Enum with values. (names) In other class I would like to enter inside a table a cell type of JCombobox that will use these enums values. my problem is to combain between string values and the enum. for example the enum class: enum item_Type {entree, main_Meal, Dessert, Drink} for example the table class: setTitle("Add new item" ); setSize(300, 80); setBackground( Color.gray ); // Create a panel to hold all other components topPanel = new JPanel(); topPanel.setLayout( new BorderLayout() ); getContentPane().add( topPanel ); //new JComboBox(item_Type.values()); JComboBox aaa = new JComboBox(); aaa = new JComboBox(item_Type.values()); TableColumn sportColumn = table.getColumnModel().getColumn(2); // Create columns names String columnNames[] = {"Item Description", "Item Type", "Item Price"}; // Create some data String dataValues[][] = {{ "0", aaa, "0" }}; // Create a new table instance table = new JTable( dataValues, columnNames ); // Add the table to a scrolling pane scrollPane = new JScrollPane( table ); topPanel.add( scrollPane, BorderLayout.CENTER ); I know that at the dataValues array I cant use aaa (the enum jcombobox). How can I do that? thanks in advance.

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  • Is there a lightweight multipart/form-data parser in C or C++?

    - by Hongli
    I'm looking at integrating multipart form-data parsing in a web server module so that I can relieve backend web applications (often written in dynamic languages) from parsing the multipart data themselves. The multipart grammar (RFC 2046) looks non-trivial and if I implement it by hand a lot of things can go wrong. Is there already a good, lightweight multipart/form-data parser written in C or C++? I'm looking for one with no external dependencies other than the C or C++ standard library. I don't need email attachment handling or buffered I/O classes or a portability runtime or whatever, just multipart/form-data parsing. Things that I've considered: GMime - depends on glib, so no go. libapreq - too large, depends on APR, badly documented, no unit tests. I've also looked at writing a parser with Ragel, but I can't figure out how to do it because the grammar is not static: the boundary can change arbitrarily.

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  • Generate and merge data with python multiprocessing

    - by Bobby
    I have a list of starting data. I want to apply a function to the starting data that creates a few pieces of new data for each element in the starting data. Some pieces of the new data are the same and I want to remove them. The sequential version is essentially: def create_new_data_for(datum): """make a list of new data from some old datum""" return [datum.modified_copy(k) for k in datum.k_list] data = [some list of data] #some data to start with #generate a list of new data from the old data, we'll reduce it next newdata = [] for d in data: newdata.extend(create_new_data_for(d)) #now reduce the data under ".matches(other)" reduced = [] for d in newdata: for seen in reduced: if d.matches(seen): break #so we haven't seen anything like d yet seen.append(d) #now reduced is finished and is what we want! I want to speed this up with multiprocessing. I was thinking that I could use a multiprocessing.Queue for the generation. Each process would just put the stuff it creates on, and when the processes are reducing the data, they can just get the data from the Queue. But I'm not sure how to have the different process loop over reduced and modify it without any race conditions or other issues. What is the best way to do this safely? or is there a different way to accomplish this goal better?

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  • Performance impact when using XML columns in a table with MS SQL 2008

    - by Sam Dahan
    I am using a simple table with 6 columns, 3 of which are of XML type, not schema-constrained. When the table reaches a size around 120,000 or 150,000 rows, I see a dramatic performance cost in doing any query in the table. For comparison, I have another table, which grows in size at about the same rate, but only contain scalar types (int, datetime, a few float columns). That table performs perfectly fine even after 200,000 rows. And by the way, I am not using XQuery on the xml columns, i am only using regular SQL query statements. Some specifics: both tables contain a DateTime field called SampleTime. a statement like (it's in a stored procedure but I show you the actual statement) SELECT MAX(sampleTime) SampleTime FROM dbo.MyRecords WHERE PlacementID=@somenumber takes 0 seconds on the table without xml columns, and anything from 13 to 20 seconds on the table with XML columns. That depends on which drive I set my database on. At the moment it sits on a different spindle (not C:) and it takes 13 seconds. Has anyone seen this behavior before, or have any hint at what I am doing wrong? I tried this with SQL 2008 EXPRESS and the full-blown SQL Server 2008, that made no difference. Oh, one last detail: I am doing this from a C# application, .NET 3.5, using SqlConnection, SqlReader, etc.. I'd appreciate some insight into that, thanks! Sam

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  • MySQL: Complex Join Statement involving two tables and a third correlation table

    - by Stephen
    I have two tables that were built for two disparate systems. I have records in one table (called "leads") that represent customers, and records in another table (called "manager") that are the exact same customers but "manager" uses different fields (For example, "leads" contains an email address, and "manager" contains two fields for two different emails--either of which might be the email from "leads"). So, I've created a correlation table that contains the lead_id and manager_id. currently this correlation table is empty. I'm trying to query the "leads" table to give me records that match either "manager" email field with the single "leads" email field, while at the same time ignoring fields that have already been added to the "correlated" table. (this way I can see how many leads that match have not yet been correlated.) Here's my current, invalid SQL attempt: SELECT leads.id, manager.id FROM leads, manager LEFT OUTER JOIN correlation ON correlation.lead_id = leads.id WHERE correlation.id IS NULL AND leads.project != "someproject" AND (manager.orig_email = leads.email OR manager.dest_email = leads.email) AND leads.created BETWEEN '1999-01-01 00:00:00' AND '2010-05-10 23:59:59' ORDER BY leads.created ASC; I get the error: Unknown column 'leads.id' in 'on clause' Before you wonder: there are records in the "leads" table where leads.project != "someproject" and leads.created falls between those dates. I've included those additional parameters for completeness.

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