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  • How Can I Find a List of All Exceptions That a Given Library Function Throws in Python?

    - by b14ck
    Sorry for the long title, but it seems most descriptive for my question. Basically, I'm having a difficult time finding exception information in the official python documentation. For example, in one program I'm currently writing, I'm using the shutil libary's move function: from shutil import move move('somefile.txt', '/tmp/somefile.txt') That works fine, as long as I have write access to /tmp/, there is enough diskspace, and if all other requirements are satisfied. However, when writing generic code, it is often difficult to guarantee those factors, so one usually uses exceptions: from shutil import move try: move('somefile.txt', '/tmp/somefile.txt') except: print 'Move failed for some reason.' I'd like to actually catch the appropriate exceptions thrown instead of just catching everything, but I simply can't find a list of exceptions thrown for most python modules. Is there a way for me to see which exceptions a given function can throw, and why? This way I can make appropriate cases for each exception, eg: from shutil import move try: move('somefile.txt', '/tmp/somefile.txt') except PermissionDenied: print 'No permission.' except DestinationDoesNotExist: print "/tmp/ doesn't exist" except NoDiskSpace: print 'No diskspace available.' Answer points go to whoever can either link me to some relevant documentation that I've somehow overlooked in the official docs, or provide a sure-fire way to figure out exactly which exceptions are thrown by which functions, and why. Thanks!

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  • VB.NET 2008, Windows 7 and saving files

    - by James Brauman
    Hello, We have to learn VB.NET for the semester, my experience lies mainly with C# - not that this should make a difference to this particular problem. I've used just about the most simple way to save a file using the .NET framework, but Windows 7 won't let me save the file anywhere (or anywhere that I have found yet). Here is the code I am using to save a text file. Dim dialog As FolderBrowserDialog = New FolderBrowserDialog() Dim saveLocation As String = dialog.SelectedPath ... Build up output string ... Try ' Try to write the file. My.Computer.FileSystem.WriteAllText(saveLocation, output, False) Catch PermissionEx As UnauthorizedAccessException ' We do not have permissions to save in this folder. MessageBox.Show("Do not have permissions to save file to the folder specified. Please try saving somewhere different.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) Catch Ex As Exception ' Catch any exceptions that occured when trying to write the file. MessageBox.Show("Writing the file was not successful.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try The problem is that this using this code throws an UnauthorizedAccessException no matter where I try to save the file. I've tried running the .exe file as administrator, and the IDE as administrator. Is this just Windows 7 being overprotective? And if so, what can I do to solve this problem? The requirements state that I be able to save a file! Thanks.

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  • Full Text Search like Google

    - by Eduardo
    I would like to implement full-text-search in my off-line (android) application to search the user generated list of notes. I would like it to behave just like Google (since most people are already used to querying to Google) My initial requirements are: Fast: like Google or as fast as possible, having 100000 documents with 200 hundred words each. Searching for two words should only return documents that contain both words (not just one word) (unless the OR operator is used) Case insensitive (aka: normalization): If I have the word 'Hello' and I search for 'hello' it should match. Diacritical mark insensitive: If I have the word 'así' a search for 'asi' should match. In Spanish, many people, incorrectly, either do not put diacritical marks or fail in correctly putting them. Stop word elimination: To not have a huge index meaningless words like 'and', 'the' or 'for' should not be indexed at all. Dictionary substitution (aka: stem words): Similar words should be indexed as one. For example, instances of 'hungrily' and 'hungry' should be replaced with 'hunger'. Phrase search: If I have the text 'Hello world!' a search of '"world hello"' should not match it but a search of '"hello world"' should match. Search all fields (in multifield documents) if no field specified (not just a default field) Auto-completion in search results while typing to give popular searches. (just like Google Suggest) How may I configure a full-text-search engine to behave as much as possible as Google? (I am mostly interested in Open Source, Java and in particular Lucene)

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  • NoSQL for filesystem storage organization and replication?

    - by wheaties
    We've been discussing design of a data warehouse strategy within our group for meeting testing, reproducibility, and data syncing requirements. One of the suggested ideas is to adapt a NoSQL approach using an existing tool rather than try to re-implement a whole lot of the same on a file system. I don't know if a NoSQL approach is even the best approach to what we're trying to accomplish but perhaps if I describe what we need/want you all can help. Most of our files are large, 50+ Gig in size, held in a proprietary, third-party format. We need to be able to access each file by a name/date/source/time/artifact combination. Essentially a key-value pair style look-up. When we query for a file, we don't want to have to load all of it into memory. They're really too large and would swamp our server. We want to be able to somehow get a reference to the file and then use a proprietary, third-party API to ingest portions of it. We want to easily add, remove, and export files from storage. We'd like to set up automatic file replication between two servers (we can write a script for this.) That is, sync the contents of one server with another. We don't need a distributed system where it only appears as if we have one server. We'd like complete replication. We also have other smaller files that have a tree type relationship with the Big files. One file's content will point to the next and so on, and so on. It's not a "spoked wheel," it's a full blown tree. We'd prefer a Python, C or C++ API to work with a system like this but most of us are experienced with a variety of languages. We don't mind as long as it works, gets the job done, and saves us time. What you think? Is there something out there like this?

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  • Indices instead of pointers in STL containers?

    - by zvrba
    Due to specific requirements [*], I need a singly-linked list implementation that uses integer indices instead of pointers to link nodes. The indices are always interpreted with respect to a vector containing the list nodes. I thought I might achieve this by defining my own allocator, but looking into the gcc's implementation of , they explicitly use pointers for the link fields in the list nodes (i.e., they do not use the pointer type provided by the allocator): struct _List_node_base { _List_node_base* _M_next; ///< Self-explanatory _List_node_base* _M_prev; ///< Self-explanatory ... } (For this purpose, the allocator interface is also deficient in that it does not define a dereference function; "dereferencing" an integer index always needs a pointer to the underlying storage.) Do you know a library of STL-like data structures (i am mostly in need of singly- and doubly-linked list) that use indices (wrt. a base vector) instead of pointers to link nodes? [*] Saving space: the lists will contain many 32-bit integers. With two pointers per node (STL list is doubly-linked), the overhead is 200%, or 400% on 64-bit platform, not counting the overhead of the default allocator.

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  • Word forms with too many ActiveX checkboxes load slowly.

    - by Luke
    Hi there, my company's software product has a feature that allows users to generate forms from Word templates. The program auto fills some fields from the SQL database and the user can fill in other data that they desire. So we have a .dotx template that holds the design of the form, and then the user gets the .docx file to fill out when they call it from our program. The problem we're having is that some of our users have been finding that the forms take an exceptionally long time to open up and then, once open, are so slow to respond (scroll around, etc) that they're unusable. So in my investigations so far, I've found out that the problem systems are one with lower powered CPUs (unfortunately it happens for systems above our system requirements) and the Word forms that cause the problems are ones with large amount of ActiveX style checkboxes on them. I verified that reducing the ActiveX checkboxes fixes the form loading problems. So I have the following questions about solutions (we're using Word 2007): 1) Is there any way to configure Word, or some other settings, so that there won't be such a strain opening a Word form with lots of ActiveX checkboxes? Any way of speeding up Word's opening? 2) Using Legacy style checkboxes instead of the ActiveX ones makes the forms load fine, but it looks like the user has to double-click the checkbox and change Default Value-Checked. Is there a way to configure it so that they can simply click on the checkbox to tick it? "Legacy Forms" checkbox as a name kind of worries me (Legacy…), does that mean a future version of word at some point wouldn't load the checkboxes because they're "legacy"? 3) Yes, it became clear to me after a little bit of research into solutions that Word is not the tool for the job for forms like I'm describing. InfoPath seems to be exactly what we should have been using all along but unfortunately I wasn't involved in the decision making or development of these forms, just tasked with coming up with a solution. I'd appreciate answers to any of these, or if anyone has any other ideas for solutions to this problem. Thanks

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  • Is it a good idea to use an integer column for storing US ZIP codes in a database?

    - by Yadyn
    From first glance, it would appear I have two basic choices for storing ZIP codes in a database table: Text (probably most common), i.e. char(5) or varchar(9) to support +4 extension Numeric, i.e. 32-bit integer Both would satisfy the requirements of the data, if we assume that there are no international concerns. In the past we've generally just gone the text route, but I was wondering if anyone does the opposite? Just from brief comparison it looks like the integer method has two clear advantages: It is, by means of its nature, automatically limited to numerics only (whereas without validation the text style could store letters and such which are not, to my knowledge, ever valid in a ZIP code). This doesn't mean we could/would/should forgo validating user input as normal, though! It takes less space, being 4 bytes (which should be plenty even for 9-digit ZIP codes) instead of 5 or 9 bytes. Also, it seems like it wouldn't hurt display output much. It is trivial to slap a ToString() on a numeric value, use simple string manipulation to insert a hyphen or space or whatever for the +4 extension, and use string formatting to restore leading zeroes. Is there anything that would discourage using int as a datatype for US-only ZIP codes?

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  • EPL (Eclipse Public Licence) for commercial usage

    - by code-gijoe
    Hi, I'm developing an application which requires a third party framework which is under an Eclipse Public Licence (EPL). The application is a server-side commercial application which will be running on my servers. The EPL software is distributed as binaries (jar files). I'm only using the packages and am not making any contribution, i.e. not making any changes to the source. Under EPL I believe I'm not a "Contributor" nor am I making a "Contribution". But if I want to make my software available to be installed at some offsite server I'm having trouble with REQUIREMENTS of EPL: b.iv - "states that source code for the Program is available from such Contributor, and informs licensees how to obtain it in a reasonable manner on or through a medium customarily used for software exchange". Does this mean that if I where to modify the source code of the 3rd party framework for my own purposes I would need to distribute all of my source code? EPL is supposed to be commercially friendly but it doesn't seem that way to me. Thank you.

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  • How to create a snowstorm on your Windows desktop?

    - by Vilx-
    Practical uses aside, how (if it is possible at all) could you create a "snowing" effect on your desktop PC running Windows? Preferably with nothing but raw C/C++ and WinAPI. The requirements for the snow are: Appears over everything else shown; Snowflakes are small, possibly simple dots or clusters of a few white pixels; Does not bother working with the computer (clicking a snowflake sends the click through to the underlying window); Plays nicely with users dragging windows; Multimonitor capable. Bonus points for any of the following features: Snow accumulates on the lower edge of the window or the taskbar (if it's at the bottom of the screen); Snow accumulates also on top-level windows. Or perhaps some snow accumulates, some continues down, accumulating on every window with a title bar; Snow accumulated on windows gets "shaken off" when windows are dragged; Snow accumulated on taskbar is aware of the extended "Start" button under Vista/7. Snowflakes have shadows/outlines, so they are visible on white backgrounds; Snowflakes have complex snowflike-alike shapes (they must still be tiny). Most of these effects are straightforward enough, except the part where snow is click-through and plays nicely with dragging of windows. In my early days I've made an implementation that draws on the HDC you get from GetDesktopWindow(), which was click-through, but had problems with users dragging windows (snowflakes rendered on them got "dragged along"). The solution may use Vista/7 Aero features, but, of course, a universal solution is preferred. Any ideas? :)

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  • Which technology should I use to transform my latex documents into html documents

    - by Matthias Günther
    Hey, I want to write a little program that transforms my TeX files into HTML. I want to parse the documents and turn the macros (the build-in and of course my own) into HTML pieces. Here are my requirements: predefined rules (e.g. begin{itemize} \item text \end{itemize} = <br> <p>text </p> <br/>) defining own CSS style ability to convert formulars (extract the formulars, load them in an imagecreator and then save the jpg/png) easy to maintain and concise I know there are several technologies out there, but I don't exactly know which is the best for me. Here are the technologies which flow into my mind Ruby (I/O is easy, formular loading via webrat), XML XSLT (I don't think that I need just overhead) perl (there are many libs out there but I'm not quite familiar with it) bash (I worked with sed and was surprised how easy it was to work with regular expressions) latex2html ... (these converters won't work for me and they don't give me freedom in parsing) Any suggestions, hints and comments are welcome. Thanks for your time, folks.

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  • Start developing a database application using Oracle + Net Beans

    - by Ranhiru
    I have thought of creating my first database application for one of my projects using Oracle and Java. I have chosen Netbeans as my development environment. I have a few questions to getting started. Please bare with me as I'm a complete beginner to Oracle + Netbeans This will be a data intensive (yet still for a college project) database application. I do not need 1000 user concurrency or any other very advanced features but basic stuff such as triggers, stored procedures etc. Will the 11g "Express" (XE) suffice for my requirements? Do i need any Java to Oracle bridge (database connectivity driver eg. ODBC etc) for Netbeans to connect to the oracle database? If yes, what are they? Does Netbeans support Oracle databases natively? Any easy to follow guide on how do i connect to the database and insert/retrieve/display data on a J2SE application? (I know that i should Google this but if there's any guide previously followed by anyone and is considered easy, it would be greatly appreciated.)

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  • Presenting collection of structures of strings in grid or similar in WPF - Example? Ideas?

    - by Andrew
    Hi, I have a collection of structures. The structure is just some strings. Example public struct ReportLine { public string Name; public string Address; public string Phone; ...// about 10 other strings } I can't change this part. What I want to do is display it in a simple grid or simlar in WPF. My only requirements are: a) need column headers b) rows must alternate in color c) columns big enough to hold largest datum (which is not know until run time) Can someone point me to an example to get me started? Is the GridView the way to go? Or DataGrid? Or perhaps just the grid? I have the book Pro WPF in C# 2008 and it covers binding ListBox's to collections, but the collections always seem to be collections of one field (ex. a collection of 40 names). Here I have a collection (an array in fact) of a structure. How do I setup the databinding? As you can see, I'm new to this and probably would most benefit from a reference to an article. I've found articles covering collections of 1 field, but no examples covering binding to an array of structures. Also, my intitial research indicates c) can't be easily done, if you demand that the column is big enough for all the data in that column, not just the visible data. Thanks, dave

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  • Should uni provide "correct answer" after programming assignment is due?

    - by Michael Mao
    Hi all: This is my very first subjective question. And I think it is programming related - the assignment is to be written in a programming language. I am not for "getting the full marks out of a subject". I am actually not for a "correct answer", but for a "better solution", so that I can compare, and can improve. I reckon it is good that I practice programming first and check the solution later to pick up the things I've done wrong/bad. Without a "benchmark" to against, this would be much harder. Unfortunately as far as I know, not all programming subjects taught in uni would kindly provide the students with a "correct answer" in the end, after the assignment is due. One bad metaphor for this is like someone asks you a question which they don't have a clear answer themselves and hope to take advantage of your answer as the basis for their answer. Personally, I feel having a assignment solution provided by the academic staff is essential to students. I do appreciate this, and I feel I might not be the only one. I am a very proactive student in uni. I learn more, I practice more, an assignment for me is more like a challenge to achieve "the best solution I can come up with", not something "I have to pass"... The cause of this question is that for the past few days I have crafted 500+ lines of Perl code, for a tiny assignment. I feel pain when I look at my solution(not finished yet) and I feel like I am an idiot doing some crap code. I know there must be a much better solution. And I reckon it is better for the lecturer in this subject to get me one, rather than asking for an answer here, even I would shamelessly add the link to my solution apart from the assignment requirements. I know in SO, there are a lot of tutors/lecturers for programming subjects/courses. I'd like to hear your words on this question.

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  • C++ Implicit Conversion Operators

    - by Imbue
    I'm trying to find a nice inheritance solution in C++. I have a Rectangle class and a Square class. The Square class can't publicly inherit from Rectangle, because it cannot completely fulfill the rectangle's requirements. For example, a Rectangle can have it's width and height each set separately, and this of course is impossible with a Square. So, my dilemma. Square obviously will share a lot of code with Rectangle; they are quite similar. For examlpe, if I have a function like: bool IsPointInRectangle(const Rectangle& rect); it should work for a square too. In fact, I have a ton of such functions. So in making my Square class, I figured I would use private inheritance with a publicly accessible Rectangle conversion operator. So my square class looks like: class Square : private Rectangle { public: operator const Rectangle&() const; }; However, when I try to pass a Square to the IsPointInRectangle function, my compiler just complains that "Rectangle is an inaccessible base" in that context. I expect it to notice the Rectangle operator and use that instead. Is what I'm trying to do even possible? If this can't work I'm probably going to refactor part of Rectangle into MutableRectangle class. Thanks.

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  • Recommendations for Continuous integration for Mercurial/Kiln + MSBuild + MSTest

    - by TDD
    We have our source code stored in Kiln/Mercurial repositories; we use MSBuild to build our product and we have Unit Tests that utilize MSTest (Visual Studio Unit Tests). What solutions exist to implement a continuous integration machine (i.e. Build machine). The requirements for this are: A build should be kicked of when necessary (i.e. code has changed in the Repositories we care about) Before the actual build, the latest version of the source code must be acquired from the repository we are building from The build must build the entire product The build must build all Unit Tests The build must execute all unit tests A summary of success/failure must be sent out after the build has finished; this must include information about the build itself but also about which Unit Tests failed and which ones succeeded. The summary must contain which changesets were in this build that were not yet in the previous successful (!) build The system must be configurable so that it can build from multiple branches(/Repositories). Ideally, this system would run on a single box (our product isn't that big) without any server components. What solutions are currently available? What are their pros/cons? From the list above, what can be done and what cannot be done? Thanks

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  • Database schema for Product Properties

    - by Chemosh
    As so many people I'm looking for a Products /Product Properties database schema. I'm using Ruby on Rails and (Thinking) Sphinx for faceted searches. Requirements: Adding new product types and their options should not require a change to the database schema Support faceted searches using Sphinx. Solutions I've come across: (See Bill Karwin's answer) Option 1: Single Table Inheritance Not an option really. The table would contain way to many columns. Option 2: Class Table Inheritance Ruby on Rails caches the database schema on start-up which means a restart whenever a new type of product is introduced. If you have a size able product catalog this could mean hundreds of tables. Option 3: Serialized LOB Kills being able to do faceted searches without heavy application logic. Option 4: Entity-Attribute-Value For testing purposes, EAV worked fine. However it could quickly become a mess and a maintenance hell as you add more and more options (e.g. when an option increase the prices or delivery time). What option should I go with? What other solutions are out there? Is there a silver bullet (ha) I overlooked?

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  • java: libraries for immutable functional-style data structures

    - by Jason S
    This is very similar to another question (Functional Data Structures in Java) but the answers there are not particularly useful. I need to use immutable versions of the standard Java collections (e.g. HashMap / TreeMap / ArrayList / LinkedList / HashSet / TreeSet). By "immutable" I mean immutable in the functional sense (e.g. purely functional data structures), where updating operations on the data structure do not change the original data, but instead return a new instance of the same kind of data structure. Also typically new and old instances of the data structure will share immutable data to be efficient in time and space. From what I can tell my options include: Functional Java Scala Clojure but I'm not sure whether any of these are particularly appealing to me. I have a few requirements/desirements: the collections in question should be usable directly in Java (with the appropriate libraries in the classpath). FJ would work for me; I'm not sure if I can use Scala's or Clojure's data structures in Java w/o having to use the compilers/interpreters from those languages and w/o having to write Scala or Clojure code. Core operations on lists/maps/sets should be possible w/o having to create function objects with confusing syntaxes (FJ looks slightly iffy) They should be efficient in time and space. I'm looking for a library which ideally has done some performance testing. FJ's TreeMap is based on a red-black tree, not sure how that rates. Documentation / tutorials should be good enough so someone can get started quickly using the data structures. FJ fails on that front. Any suggestions?

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  • Integration transport choice (Oracle + SQL Server)

    - by lak-b
    We have several systems with Oracle (A) and SQL Server (B) databases on backend. I have to consolidate data from those systems into the new SQL Server database. Something like that: (A) =>|---------------| | some software | => SQL Server (B) =>|---------------| where some software is: transport (A and B systems located in the network) processing business logic (custom .NET code) Due to first point, I need some queue software or something similar (like MSMQ, Service Broker or something). In another hand, I can implement a web-service instead of queue. (A) =>|---------------|-------------| | queue/service | custom code | => SQL Server (B) =>|---------------|-------------| The question is: which queue/transport framework should I use with Oracle and SQL Server databases? It would be nice, if I can post messages to MSMQ in both Oracle and SQL Server stored procedures (can I?) It would be nice, if I can call a web-service in both Oracle and SQL Server stored procedures (can I?) It would be nice, if I can use something similar in both Oracle and SQL Server stored procedures (what exactly?) What software should I prefer to my requirements?

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  • Why should I use core.autocrlf in Git

    - by Rich
    I have a Git repository that is accessed from both Windows and OS X, and that I know already contains some files with CRLF line-endings. As far as I can tell, there are two ways to deal with this: Set core.autocrlf to false everywhere, Follow the instructions here (echoed on GitHub's help pages) to convert the repository to contain only LF line-endings, and thereafter set core.autocrlf to true on Windows and input on OS X. The problem with doing this is that if I have any binary files in the repository that: a). are not correctly marked as binary in gitattributes, and b). happen to contain both CRLFs and LFs, they will be corrupted. It is possible my repository contains such files. So why shouldn't I just turn off Git's line-ending conversion? There are a lot of vague warnings on the web about having core.autocrlf switched off causing problems, but very few specific ones; the only that I've found so far are that kdiff3 cannot handle CRLF endings (not a problem for me), and that some text editors have line-ending issues (also not a problem for me). The repository is internal to my company, and so I don't need to worry about sharing it with people with different autocrlf settings or line-ending requirements. Are there any other problems with just leaving line-endings as-is that I am unaware of?

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  • Social Media Java Design Problem

    - by jboyd
    I need to put something together quickly that will take blog posts and place them on social media sites, the requirements are as follows: Blog Entries are independent records that already exist, they have a published date and a modified date, the blog entry application cannot be changed, at least not substantially A new blog entry, or update needs to be sent to social media sites I currently do not need to update or delete social media communications if the blog entry is edited, or deleted, though I may need to later My design problems here are as follows: how do I know the status of each update how can I figure out what blog entry updates and postings have already been sent out? how can I quickly poll the blog entry table for postings that haven't yet been sent out? Avoiding looking at each Entry record from the DB as an object and asking if it's been sent already. That would be too slow. I cannot hook into any Blog Entry update code, my only option would be to create a trigger that an update queues something to be processed I'm looking for general guiding principles here, the biggest problem I'm having is coming up with any reasonable way to figure out if a blog entry should be sent to our social media sites in the first place

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  • import csv file/excel into sql database asp.net

    - by kiev
    Hi everyone! I am starting a project with asp.net visual studio 2008 / SQL 2000 (2005 in future) using c#. The tricky part for me is that the existing DB schema changes often and the import files columns will all have to me matched up with the existing db schema since they may not be one to one match on column names. (There is a lookup table that provides the tables schema with column names I will use) I am exploring different ways to approach this, and need some expert advice. Is there any existing controls or frameworks that I can leverage to do any of this? So far I explored FileUpload .NET control, as well as some 3rd party upload controls to accomplish the upload such as SlickUpload but the files uploaded should be < 500mb Next part is reading of my csv /excel and parsing it for display to the user so they can match it with our db schema. I saw CSVReader and others but for excel its more difficult since I will need to support different versions. Essentially The user performing this import will insert and/or update several tables from this import file. There are other more advance requirements like record matching but and preview of the import records, but I wish to get through understanding how to do this first. Update: I ended up using csvReader with LumenWorks.Framework for uploading the csv files.

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  • design an extendable database model

    - by wishi_
    Hi! Currently I'm doing a project whose specifications are unclear - well who doesn't. I wonder what's the best development strategy to design a DB, that's going to be extended sooner or later with additional tables and relations. I want to include "changeability". My main concern is that I want to apply design patterns (it's a university project) and I want to separate the constant factors from those, that change by choosing appropriate design patterns - in my case MVC and a set of sub-patterns at model level. When it comes to the DB however, I may have to resdesign my model in my MVC approach, because my domain model at a later stage my require a different set of classes representing the DB tables. I use Hibernate as an abstraction layer between DB and application. Would you start with a very minimal DB, just a few tables and relations? And what if I want an efficient DB, too? I wonder what strategies are applied in the real world. Stakeholder analysis for example isn't a sufficient planing solution when it comes to changing requirements. I think - at a DB level - my design pattern ends. So there's breach whose impact I'd like to minimize with a smart strategy.

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  • Ember Data Sycn - LocalStorage+REST+RealTime+Online/Offline

    - by Miguel Madero
    We have a combination of requirements in terms o data access. Pre-load some reference data. We need reference data to survive browser restarts instead of just living in memory to avoid loading it all the time. I'm currently using the LocalStorageAdapter for that. Once we have it, we would like to sync changes (polling or using Socket.IO in the background and updating the LocalStorage could do the trick) There're other models that are more transactional, where we would need to directly go to the Server and get/save them. It would be nice to use something like the RESTAdapter for that. Lastly, there're some operations that should work off-line and changes should be synced later. To make it more concrete: * We pre-load vendor and "favorite products" into Local Storage. We work offline with those. * We need to sync server changes to vendor and product information. * If they search the full catalog, that requires them to be online. * When offline, we need to allow users to add something to their cart or even submit and order. We would like to queue this action and submit it when they have an Internet Connection. So a few questions are derived from this: * Is there a way to user RESTAdapter in combination with LocalStorage? * Is there some Socket.IO support? (Happy to do this part manually) * Is there Queueing support? Ideally at the Ember-Data level. I know we will have to do a lot of this manually and pull together the different lego pieces, but I wanted to ask for some perspective from experience Ember devs.

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  • Improve this generic abstract class

    - by Keivan
    I have the following abstract class design, I was wondering if anyone can suggest any improvements in terms of stronger enforcement of our requirements or simplifying implementing of the ControllerBase. //Dependency Provider base public abstract class ControllerBase<TContract, TType> where TType : TContract, class { public static TContract Instance { get { return ComponentFactory.GetComponent<TContract, TType>(); } } public TContract GetComponent<TContract, TType>() where TType : TContract, class { component = (TType)Activator.CreateInstance(typeof(TType), true); RegisterComponentInstance<TContract>(component); } } //Contract public interface IController { void DoThing(); } //Actual Class Logic public class Controller: ControllerBase<IController,Controller> { public void DoThing(); //internal constructor internal Controller(){} } //Usage public static void Main() { Controller.Instance.DoThing(); } The following facts should always be true, TType should always implement TContract (Enforced using a generic constraint) TContract must be an interface (Can't find a way to enforce it) TType shouldn't have public constructor, just an internal one, is there any way to Enforce that using ControllerBase? TType must be an concrete class (Didn't include New() as a generic constrain since the constructors should be marked as Internal)

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  • Is it Possible to Use Constraints on Hierarchical Data in a Self-Referential Table?

    - by pbarney
    Suppose you have the following table, intended to represent hierarchical data: +--------+-------------+ | Field | Type | +--------+-------------+ | id | int(10) | | parent | int(10) | | name | varchar(45) | +--------+-------------+ The table is self-referential in that the parent_id refers to id. So you might have the following data: +----+--------+---------------+ | id | parent | name | +----+--------+---------------+ | 1 | 0 | fruit | | 2 | 0 | vegetable | | 3 | 1 | apple | | 4 | 1 | orange | | 5 | 3 | red delicious | | 6 | 3 | granny smith | | 7 | 3 | gala | +----+--------+---------------+ Using MySQL, I am trying to impose a (self-referential) foreign key constraint upon the data to cascade on update and prevent deletion of a record if it has any "children." So I used the following: CREATE TABLE `test`.`fruit` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `parent` INT(10) UNSIGNED, `name` VARCHAR(45) NOT NULL, PRIMARY KEY (`id`), CONSTRAINT `fk_parent` FOREIGN KEY (`parent`) REFERENCES `fruit` (`id`) ON UPDATE CASCADE ON DELETE RESTRICT ) ENGINE = InnoDB; From what I understand, this should fit my requirements. (And parent must default to null to allow insertions, correct?) The problem is, if I change the id of a record, it will not cascade: Cannot delete or update a parent row: a foreign key constraint fails (`test`.`fruit`, CONSTRAINT `fk_parent` FOREIGN KEY (`parent`) REFERENCES `fruit` (`id`) ON UPDATE CASCADE) What am I missing? Feel free to correct me if my terminology is screwed up... I'm new to constraints.

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