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  • MongoDB RSS Feed Entries, Embed the Entries in the Feed Object?

    - by Patrick Klingemann
    I am saving a reference to an RSS Feed in MongoDB, each Feed has an ever growing list of Entries. As I'm designing my schema, I'm concerned about this statement from the MongoDB Schema Design - Embed vs. Reference Documentation: If the amount of data to embed is huge (many megabytes), you may read the limit on size of a single object. This will surely happen if I understand the statement correctly. So the question is, I am correct to assume that I should not embed the Feed Entries within a Feed because I'll eventually reach the limit on size of a single object?

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  • In Prism (CAL), how can I RegisterPresenterWithRegion instead of RegisterViewWithRegion

    - by Edward Tanguay
    I have a module in a Prism application and in its initialize method I want to register a presenter instead of a view with a region, i.e. I want to do this: PSEUDO-CODE: regionManager.RegisterPresenterWithRegion( "MainRegion", typeof(Presenters.EditCustomerPresenter)); instead of loading a view like this: regionManager.RegisterViewWithRegion( "MainRegion", typeof(Views.EditCustomerView)); The presenter would of course bring along its own view and ultimately register this view in the region, but it would allow me to bind the presenter to the view in the presenter's constructor instead of binding the two together in XAML (which is more of a decoupled MVVM pattern which I want to avoid here). How can I add a Presenter to a Region instead of a view? namespace Client.Modules.CustomerModule { [Module(ModuleName = "CustomerModule")] public class CustomerModule : IModule { private readonly IRegionManager regionManager; public CustomerModule(IRegionManager regionManager) { this.regionManager = regionManager; } public void Initialize() { regionManager.RegisterViewWithRegion("MainRegion", typeof(Views.EditCustomerView)); } } }

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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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  • Active Record/ORM vs Normal Forms?

    - by Arsenal
    Hello, I've been playing around with Active Record a bit, and I have noticed that A.C./ORM always uses the following database model when creating a one-to-one relationship Person id | country_id | name | ... Country id | tld | name | ... No I wondered, isn't this a violiation of the third Normal Form? This clearly states "Every non-prime attribute is non-transitively dependent on every key of the table". Well this country_id isn't dependent of personid is it? So is this wrong or am I just not getting the point?

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  • Is there a modern (eg NoSQL) web analytics solution based on log files?

    - by Martin
    I have been using Awstats for many years to process my log files. But I am missing many possibilities (like cross-domain reports) and I hate being stuck with extra fields I created years ago. Anyway, I am not going to continue to use this script. Is there a modern apache logs analytics solution based on modern storage technologies like NoSQL or at least somehow ready to cope with large datasets efficiently? I am primarily looking for something that generates nice sortable and searchable outputs with the focus on web analytics, before having to write my own frontends. (so graylog2 is not an option) This question is purely about log file based solutions.

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  • Database Modelling - Conceptually different entities but with near identical fields

    - by Andrew Shepherd
    Suppose you have two sets of conceptual entities: MarketPriceDataSet which has multiple ForwardPriceEntries PoolPriceForecastDataSet which has multiple PoolPriceForecastEntry Both different child objects have near identical fields: ForwardPriceEntry has MarketPriceDataSetId (foreign key to parent table) StartDate EndDate SimulationItemId ForwardPrice PoolPriceForecastEntry has PoolPriceForecastDataSetId (foreign key to parent table) StartDate EndDate SimulationItemId ForecastPoolPrice If I modelled them as separate tables, the only difference would be the foreign key, and the name of the price field. There has been a debate as to whether the two near identical tables should be merged into one. Options I've thought of to model this is: Just keep them as two independent, separate tables Have both sets in the one table with an additional "type" field, and a parent_id equalling a foreign key to either parent table. This would sacrifice referential integrity checks. Have both sets in the one table with an additional "type" field, and create a complicated sequence of joining tables to maintain referential integrity. What do you think I should do, and why?

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  • How set opacity on QGraphicsItem

    - by La Chamelle
    Hello, i have a inherited from QGraphicsScene and QGraphicsItem to create my own classes. I use Qt 4.6. I want to set a specific opacity on each items of my scene. I use setOpacity : setOpacity method, but its not the result i hope. I want to have for example one item opaque and an other transparent (to see the desktop, or the other application). But if i dont set the opacity of the QGraphicsView to 0.5, i have not the transparancy. And if the QGraphicsView is set to 0.5, the item is not real opaque. What should i do ? Thanks you.

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  • How to create skype like message window?

    - by Miraaj
    Hi all, I am just trying to design skype like message window , for this I have taken the NSDrawer element. It contains : a table view on left, menu items on top, text field on right bottom and text view at central portion on right side. Using text view I can play with string being displayed but I cannot draw the line between messages or round rectangle surrounding user name and time stamp. Can anyone suggest me how can I achieve same look and feel for central message view as in skype?? or is there any better control then NSTextView to be used for it?? Thanks, for any suggestion... Miraaj

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  • How to create new account using servlets

    - by Alvin
    I want to know how can I create new account using servlets in post method? I'm currently following MVC design pattern, and I want to know if I pass the required data to register new account from JSP page, then how can I get that data in post method? As request.getParameter() method returning me null. How can I know that post method is calling to create new account? How can I pass all the relevant user information from servlets to model class for registering data to the database table?

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  • Are there any Java based libraries that provide game mapping features?

    - by James.Elsey
    Hi All, I'm working on a Java web based game in my spare time (springMVC / JSPs etc), and I'm wondering what are my options for dealing with the "game world" or mapping element. My game will be 2d / text based, so I have no need for any OpenGL / Flash etc. My initial idea was to use Google maps and provide a custom overlay, but I want to know if there are any alternatives? For example, if I create a 2d map with all my zones, are there any libraries that will help me plot players, work out distances and so forth? Regards

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  • javascript: execute a bunch of asynchronous method with one callback

    - by Samuel Michelot
    I need to execute a bunch of asynchronous methods (client SQLite database), and call only one final callback. Of course, the ugly way is: execAll : function(callBack) { asynch1(function() { asynch2(function() { ... asynchN(function() { callBack(); }) }) }); } But I know there are better ways to do it. Intuitively I would detect when all call back has been called with a counter to call the final callback. I think this is a common design-pattern, so if someone could point me in the right direction... Thanks in advance !

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  • MVP - asp.net - passing information via views - confused

    - by ekynox
    Hi, I've just started to play around with MVP in asp.net. One thing I quite cant figure out is how do I pass information, i.e. an integer variable from one view(webform) to another. Let's I have a customerlistView which is mapped to a customerlist.aspx page. From it I select a customer and it's record id. Say I want to display the customer's details in another view (i.e customerDetailView, customerdetail.aspx). How do I achieve that ? Does that mean customerlistView would call the presenter of the customerdetail and cause a page redirect ? Any ideas ? thanks

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  • Rails :dependent => :destroy VS :dependent => :delete_all

    - by Sergey
    In rails guides it's described like this: "Objects will be in addition destroyed if they’re associated with :dependent = :destroy, and deleted if they’re associated with :dependent = :delete_all." Right, cool. But what's the difference between being destroyed and being deleted? I tried both and it seems to do the same thing.

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  • Database layout tagging system

    - by Kurresmack
    I am creating a web site for a customer and they want to be able to create articles. My idea is to tag them so I am going to implement the system. What is the best design, both from an architectural and a perfomance perspective: 1. To have table with all tags and then have a one to many relationship table that links a tag like this: articles table with ID tags table with ID one to many table with columns Article.ID and Tags.ID 2. To have one table with articles and one with tags for articles like this: articles table with ID tags table with Article.ID and tag text Thanks in advance!

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  • How can I share Configuration Settings across multiple projects in Visual Studio?

    - by Muneeb
    Ok I know this may be a design issue, so I would love to have remarks on that as well. I have a Visual Studio web application solution. I have three projects as UserInterface, BusinessLogic and DataAccess. I had to store some user defined settings and I created configSections in the config file. I access these configSections through classes which inherit from .NET's ConfigurationSection base class. So in short for every project I had a separate configSection and for that corresponding configSection I had a class in that project inheriting from ConfigurationSection to access the config section settings. This works all sweet. But the problem arises if there is any setting which I need to use across multiple projects. So If I need to use a setting defined in UserInterface project configSection in, let say, BusinessLogic project I have to actually make a copy of that setting in the BusinessLogic's configSection. This ends up having the same setting copied across multiple configSections. Isn't this a bit too redundant?

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  • Using a "vo" for joined data?

    - by keithjgrant
    I'm building a small financial system. Because of double-entry accounting, transactions always come in batches of two or more, so I've got a batch table and a transaction table. (The transaction table has batch_id, account_id, and amount fields, and shared data like date and description are relegated to the batch table). I've been using basic vo-type models for each table so far. Because of this table structure structure, though, transactions will almost always be selected with a join on the batch table. So should I take the selected records and splice them into two separate vo objects, or should I create a "shared" vo that contains both batch and transaction data? There are a few cases in which batch records and/or transaction records. Are there possible pitfalls down the road if I have "overlapping" vo classes?

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  • Lackadaisical One-to-One between Char and Byte Streams

    - by Vaibhav Bajpai
    I expected to have a one-to-one correspondence between the character streams and byte streams in terms of how the classes are organized in their hierarchy. FilterReader and FilterWriter (character streams) correspond back to FilterInputStream and FilterOutputStream (byte stream) classes. However I noticed few changes as - BufferedInputStream extends FilterInputStream, but BufferedReader does NOT extend FilterReader. BufferedOutputStream and PrintStream both extend FilterOutputStream, but BufferedWriter and PrintWriter does NOT extend FilterWriter. FilterInputStream and FilterOutputStream are not abstract classes, but FilterReader and FilterWriter are. I am not sure if I am being too paranoid to point out such differences, but was just curious to know if there was design reasoning behind such decision.

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  • Surrogate key for date dimension?

    - by Navin
    There are 2 school of thoughts : Use surrogate key preferbly in the format of YYYYMMDD as this will always be sequential. Eliminate Date dimension surrogate key and use actual date instead. My Questions to experts on dimension modeling are : 1> Which design would you prefer and why ? 2> How should we handle unknown values in each of the cases, Can we simply place NULL in Fact table for unknown dates as Foreign Key can be NULL (if no why)? 3> If we need to partition fact table on date column ,how would we achieve that in case 1. I am inclined towards using actual date and using NULL to represent UNKNOWN dates in fact table , as date related validation on fact can be done without need to look in to dimension table.

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  • Is there such a thing as too many tables?

    - by Stacey
    I've been searching stackoverflow for about an hour now and couldn't find any topics related, so I apologize if this is a duplicate question. My inquery is this. Is there a point at which there are too many tables in a database? Even if the structure is well organized, thought out, and perfectly facilitates the design intent? I have a database that is quickly approaching 40 tables - about 10 main ones, and over 30 ancillary tables (junction tables, 'enumeration' tables, etc). Am I just a bad developer - or should I be trying something different? It seems like so many to me, I'm really afraid at how it will impact the performance of the project. I have done a lot of condensing where possible, grouped similar things where possible, etc. The database is built in MS-SQL 2008.

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  • Is there a standard practice for storing default application data?

    - by Rox Wen
    Our application includes a default set of data. The default data includes coefficients and other factors that are unlikely to ever change but still need to be update-able by the user. Currently, the original default data is stored as a populated class within the application. Data updates are stored to an external XML file. This design allows us to include a "reset" feature to restore the original default data. Our rationale for not storing defaults externally [e.g. XML file] was to minimize the risk of being altered. The overall volume of data doesn't warrant a database. Is there a standard practice for storing "default" application data?

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  • How do I add a one-to-one relationship in MYSQL?

    - by alex
    +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | pid | varchar(99) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+ 1 row in set (0.00 sec) +-------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------------+------+-----+---------+-------+ | pid | varchar(2000) | YES | | NULL | | | recid | varchar(2000) | YES | | NULL | | +-------+---------------+------+-----+---------+-------+ 2 rows in set (0.00 sec) This is my table. pid is just the id of the user. "recid" is a recommended song for that user. I hope to have a list of pid's, and then recommended songs for each person. Of course, in my 2nd table, (pid, recid) would be unique key. How do I do a one-to-one query for this ?

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  • MVC using ODP.NET getting ORA-01840

    - by sse
    I am writing a simple MVC Application using ODP.NET. I am trying to call a Pl/Sql proc that inserts a record. Here is the simple Pl/Sql: procedure spAddCountry(pGisRecid in country.GISRECID%type, pCountryCode in country.COUNTRYCODE%type, pCountryName in country.COUNTRYNAME%type, pCurrencyCode in country.CURRENCYCODE%type, pEUTerritory in country.EUTERRITORY%type, pFatCAStatus in country.FATCASTATUS%type, pFATF in country.FATF%type, pFSCountryCode in country.COUNTRYCODE%type, pInsertedBy in country.INSERTEDBY%type, pInsertedOn in country.INSERTEDON%type, pLanguages in country.LANGUAGES%type, pNCCT in country.NCCT%type) is PRAGMA AUTONOMOUS_TRANSACTION; begin INSERT INTO COUNTRY (GISRECID, COUNTRYCODE, COUNTRYNAME, CURRENCYCODE, EUTERRITORY, FATCASTATUS, FATF, FSCOUNTRYCODE, INSERTEDBY, INSERTEDON, LANGUAGES, NCCT) VALUES(pGISRECID, pCOUNTRYCODE, pCOUNTRYNAME, pCURRENCYCODE, pEUTERRITORY, pFATCASTATUS, pFATF, pFSCOUNTRYCODE, pINSERTEDBY, pINSERTEDON, pLANGUAGES, pNCCT); Commit; end; I am having difficulty passing the date parameter, pInsertedOn, to the Stored Proc. I have verified that the web form retrieves the form data successfully and calls the AddCountry method below, which in turns calls the stored proc, spAddCountry, after populating all of the parms. Here is a snippet of the MVC C# code. I get the following exception: "ORA-01840 input value not long enough for date format". public void AddCountry(Country aCountry) //because the country object field names match the form field names they automatically get bound!! { string oradb = "Data Source=XYZ;User Id=XYZ;Password=xyz;"; OracleConnection conn = new OracleConnection(oradb); OracleCommand cmd = conn.CreateCommand(); cmd.CommandText = "tstpack.spAddCountry"; cmd.CommandType = CommandType.StoredProcedure; ... OracleParameter paramInsertedBy = new OracleParameter(); paramInsertedBy.ParameterName = "pInsertedBy"; paramInsertedBy.Value = aCountry.InsertedBy; cmd.Parameters.Add(paramInsertedBy); // CultureInfo ci = new CultureInfo("en-US"); OracleParameter paramInsertedOn = new OracleParameter(); paramInsertedOn.ParameterName = "pInsertedOn"; // paramInsertedOn.Value = DateTime.Now; //just testing to see if it's WebForm issue // paramInsertedOn.Value = Convert.ToDateTime(DateTime.Now.ToString(), ci); //flail! paramInsertedOn.Value = aCountry.InsertedOn; cmd.Parameters.Add(paramInsertedOn); ... conn.Open(); cmd.ExecuteNonQuery(); //CRASH! ORA-01840 conn.Close(); } Just to verify that the flow of the program is working, I tried removing the date parm "pInsertedOn" from the pl/sql and from the parm list above, and everything worked fine. I know I am going off of the rails with the date. Can someone tell me how to pass a date to Oracle from an MVC WebForm? Is there some sort of type cast needed? I would really appreciate an example too. Thanks so much! ps, I did try changing the parm type to Varchar2 in the Pl/Sql and doing some conversions myself in the Pl/Sql, the automatic MVC binder was getting in my way, forcing the property of paramInsertedOn.OracleType to DateTime. I tried forcing it to Varchar2, but no luck there either...

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