Search Results

Search found 67075 results on 2683 pages for 'data model'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 451/2683 | < Previous Page | 447 448 449 450 451 452 453 454 455 456 457 458  | Next Page >

  • How to index a table with a Type 2 slowly changing dimension for optimal performance

    - by The Lazy DBA
    Suppose you have a table with a Type 2 slowly-changing dimension. Let's express this table as follows, with the following columns: * [Key] * [Value1] * ... * [ValueN] * [StartDate] * [ExpiryDate] In this example, let's suppose that [StartDate] is effectively the date in which the values for a given [Key] become known to the system. So our primary key would be composed of both [StartDate] and [Key]. When a new set of values arrives for a given [Key], we assign [ExpiryDate] to some pre-defined high surrogate value such as '12/31/9999'. We then set the existing "most recent" records for that [Key] to have an [ExpiryDate] that is equal to the [StartDate] of the new value. A simple update based on a join. So if we always wanted to get the most recent records for a given [Key], we know we could create a clustered index that is: * [ExpiryDate] ASC * [Key] ASC Although the keyspace may be very wide (say, a million keys), we can minimize the number of pages between reads by initially ordering them by [ExpiryDate]. And since we know the most recent record for a given key will always have an [ExpiryDate] of '12/31/9999', we can use that to our advantage. However... what if we want to get a point-in-time snapshot of all [Key]s at a given time? Theoretically, the entirety of the keyspace isn't all being updated at the same time. Therefore for a given point-in-time, the window between [StartDate] and [ExpiryDate] is variable, so ordering by either [StartDate] or [ExpiryDate] would never yield a result in which all the records you're looking for are contiguous. Granted, you can immediately throw out all records in which the [StartDate] is greater than your defined point-in-time. In essence, in a typical RDBMS, what indexing strategy affords the best way to minimize the number of reads to retrieve the values for all keys for a given point-in-time? I realize I can at least maximize IO by partitioning the table by [Key], however this certainly isn't ideal. Alternatively, is there a different type of slowly-changing-dimension that solves this problem in a more performant manner?

    Read the article

  • Strategy to structure a search index in a relational database

    - by neilc
    I am interested in suggestions for building an efficient and robust structure for indexing products in a new database I am building (i'm using MySql) When a product is entered through the form there are three parts I am interested in indexing for searching purposes. The product title The product description Tags The most important is title, followed by tags, followed by the description. I was thinking of using the following structure CREATE TABLE `searchindex` ( `id` INT NOT NULL , `word` VARCHAR( 255 ) NOT NULL , `weighting` INT NOT NULL , `product_id` INT NOT NULL , PRIMARY KEY ( `id` ) ) Then each time a product is created I would split apart the title, description and tags (removing common words) and award them a weighting. Then it is trivial to select out the words and corresponding products and order them by weighting. Is there a better way to do this? I would be worried that this strategy would slow down over time and as the database filled up.

    Read the article

  • Should a Trim method generally in the Data Access Layer or with in the Domain Layer?

    - by jpierson
    I'm dealing with a database that contains data with inconsistencies such as white leading and trailing white space. In general I see a lot of developers practice defensive coding by trimming almost all strings that come from the database that may have been entered by a user at some point. In my oppinoin it is better to do such formating before data is persisted so that it is done only once and then the data can be in a consistent and reliable state. Unfortunatley this is not the case however which leads me to the next best solution, using a Trim method. If I trim all data as part of my data access layer then I don't have to concern myself with defensive trimming within the business objects of my domain layer. If I instead put the trimming responsibility in my business objects, such as with set accessors of my C# properties, I should get the same net results however the trim will be operating on all values assigned to my business objects properties not just the ones that come from the inconsistent database. I guess as a somewhat philisophical question that may determine the answer I could ask "Should the domain later be responsible for defensive/coercive formatting of data?" Would it make sense to have a set accessor for a PhoneNumber property on a business object accept a unformatted or formatted string and then attempt to format it as required or should this responsibility be pushed to the presentation and data access layers leaving the domain layer more strict in the type of data that it will accept? I think this may be the more fundamental question. Update: Below are a few links that I thought I should share about the topic of data cleansing. Information service patterns, Part 3: Data cleansing pattern LINQ to SQL - Format a string before saving? How to trim values using Linq to Sql?

    Read the article

  • Data not synchornizing java sockets

    - by Droid_Interceptor
    I am writing a auction server and client and using a class called BidHandler to deal with the bids another class AuctionItem to deal with the items for auction. The main problem I am having is little synchroization problem. Screen output of client server as can see from the image at 1st it takes the new bid and changes the value of the time to it, but when one the user enters 1.0 the item seems to be changed to that. But later on when the bid changes again to 15.0 it seems to stay at that price. Is there any reason for that. I have included my code below. Sorry if didnt explain this well. This is the auction client import java.io.*; import java.net.*; public class AuctionClient { private AuctionGui gui; private Socket socket; private DataInputStream dataIn; private DataOutputStream dataOut; //Auction Client constructor String name used as identifier for each client to allow server to pick the winning bidder public AuctionClient(String name,String server, int port) { gui = new AuctionGui("Bidomatic 5000"); gui.input.addKeyListener (new EnterListener(this,gui)); gui.addWindowListener(new ExitListener(this)); try { socket = new Socket(server, port); dataIn = new DataInputStream(socket.getInputStream()); dataOut = new DataOutputStream(socket.getOutputStream()); dataOut.writeUTF(name); while (true) { gui.output.append("\n"+dataIn.readUTF()); } } catch (Exception e) { e.printStackTrace(); } } public void sentBid(String bid) { try { dataOut.writeUTF(bid); } catch(IOException e) { e.printStackTrace(); } } public void disconnect() { try { socket.close(); } catch(IOException e) { e.printStackTrace(); } } public static void main (String args[]) throws IOException { if(args.length!=3) { throw new RuntimeException ("Syntax: java AuctionClient <name> <serverhost> <port>"); } int port = Integer.parseInt(args[2]); AuctionClient a = new AuctionClient(args[0],args[1],port); } } The Auction Server import java.io.*; import java.net.*; import java.util.*; public class AuctionServer { public AuctionServer(int port) throws IOException { ServerSocket server = new ServerSocket(port); while(true) { Socket client = server.accept(); DataInputStream in = new DataInputStream(client.getInputStream()); String name = in.readUTF(); System.out.println("New client "+name+" from " +client.getInetAddress()); BidHandler b = new BidHandler (name, client); b.start(); } } public static void main(String args[]) throws IOException { if(args.length != 1) throw new RuntimeException("Syntax: java AuctionServer <port>"); new AuctionServer(Integer.parseInt(args[0])); } } The BidHandler import java.net.*; import java.io.*; import java.util.*; import java.lang.Float; public class BidHandler extends Thread { Socket socket; DataInputStream in; DataOutputStream out; String name; float currentBid = 0.0f; AuctionItem paper = new AuctionItem(" News Paper ", " Free newspaper from 1990 ", 1.0f, false); protected static Vector handlers = new Vector(); public BidHandler(String name, Socket socket) throws IOException { this.name = name; this.socket = socket; in = new DataInputStream (new BufferedInputStream (socket.getInputStream())); out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream())); } public synchronized void run() { try { broadcast("New bidder has entered the room"); handlers.addElement(this); while(true) { broadcast(paper.getName() + paper.getDescription()+" for sale at: " +paper.getPrice()); while(paper.getStatus() == false) { String message = in.readUTF(); currentBid = Float.parseFloat(message); broadcast("Bidder entered " +currentBid); if(currentBid > paper.getPrice()) { paper.setPrice(currentBid); broadcast("New Higgest Bid is "+paper.getPrice()); } else if(currentBid < paper.getPrice()) { broadcast("Higgest Bid is "+paper.getPrice()); } else if(currentBid == paper.getPrice()) { broadcast("Higgest Bid is "+paper.getPrice()); } } } } catch(IOException ex) { System.out.println("-- Connection to user lost."); } finally { handlers.removeElement(this); broadcast(name+" left"); try { socket.close(); } catch(IOException ex) { System.out.println("-- Socket to user already closed ?"); } } } protected static void broadcast (String message) { synchronized(handlers) { Enumeration e = handlers.elements(); while(e.hasMoreElements()) { BidHandler handler = (BidHandler) e.nextElement(); try { handler.out.writeUTF(message); handler.out.flush(); } catch(IOException ex) { handler = null; } } } } } The AuctionItem Class class AuctionItem { String itemName; String itemDescription; float itemPrice; boolean itemStatus; //Create a new auction item with name, description, price and status public AuctionItem(String name, String description, float price, boolean status) { itemName = name; itemDescription = description; itemPrice = price; itemStatus = status; } //return the price of the item. public synchronized float getPrice() { return itemPrice; } //Set the price of the item. public synchronized void setPrice(float newPrice) { itemPrice = newPrice; } //Get the status of the item public synchronized boolean getStatus() { return itemStatus; } //Set the status of the item public synchronized void setStatus(boolean newStatus) { itemStatus = newStatus; } //Get the name of the item public String getName() { return itemName; } //Get the description of the item public String getDescription() { return itemDescription; } } There is also simple GUI to go with this that seems to be working fine. If anyone wants it will include the GUI code.

    Read the article

  • Using awk to return only certain chunks of data

    - by Koriar
    I'm not 100% certain how to phrase my question simply, so I apologize if this has been answered somewhere and I was just unable to find it. What I have are debug logs with authentication packets in them along with a bunch of other output. I need to search through about 2 million lines of logs to find every packet that contains a certain mac address. The packets look something like this (slightly censored): -----------------[ header ]----------------- Event: Authd-Response (1900) Sequence: -54 Timestamp: 1969-12-31 19:30:00 (0) ---------------[ attributes ]--------------- Auth-Result = Auth-Accept Service-Profile-SID = 53 Service-Profile-SID = 49 RADIUS-Access-Accept-Attr/WiMAX-Capability = 0x(numbers) Session-Timeout = 3600 Service-Profile-SID = 4 Service-Profile-SID = 29 Chargeable-User-Identity = "(Numbers)" User-Password = "(the MAC address I'm looking for)" -------------------------------------------- However there are about 10 different possible types with different possible lengths. They all start with the header line and end with the all-dashes line. I've had success using awk to get the code blocks themselves using this: awk '/-----------------\[ header \]-----------------/,/--------------------------------------------/' filename.txt But I was hoping to be able to use it to return only the packets which contain the MAC address that I need. I've been trying to figure this out for a few days now and I'm pretty stuck. I could try and write a bash script, but I could swear that I've used awk to do something like this before...

    Read the article

  • How should my application keep clients in sync with schema changes to HTML5 databases?

    - by Chad Johnson
    I'm wanting to incorporate HTML5 database storage into my web application to make it online-accessible. I've done lots of development in server-side environments with databases, and we all know that database schema additions and modifications are often necessary. I am wondering what should happen if my application uses an offline database schema, and that schema changes. How do I prevent the application from breaking on the client side? How do I ensure the database is always up to date on the client end? Anyone have any solutions?

    Read the article

  • How to convert an application to be a database independent app ?

    - by Eslam
    I have a java web application that has informix DB as it's back end database , now i take a decision to make my app work with SqlServer so i changed all the informix related syntax into SqlServer, and i may take a decision in the future to switch into oracle so the pain will be repeated again and again, as a result i decided to make my application a DataBase independent one that's able to work with any DB vendor smoothly, but i have no idea till now about how to do that, so your ideas is welcomed.

    Read the article

  • GZipStream in an WebHttpResponse producing no data

    - by Pierre 303
    I want to compress my HTTP Responses for client that supports it. Here is the code used to send a standard response: IHttpClientContext context = (IHttpClientContext)sender; IHttpRequest request = e.Request; string responseBody = "This is some random text"; IHttpResponse response = request.CreateResponse(context); using (StreamWriter writer = new StreamWriter(response.Body)) { writer.WriteLine(responseBody); writer.Flush(); response.Send(); } The code above works fine. Now I added gzip support below. When I test it with a browser that supports gzip or a custom method, it returns an empty string. I'm sure I'm missing something simple, but I just can't find it... IHttpClientContext context = (IHttpClientContext)sender; IHttpRequest request = e.Request; string acceptEncoding = request.Headers["Accept-Encoding"]; string responseBody = "This is some random text"; IHttpResponse response = request.CreateResponse(context); if (acceptEncoding != null && acceptEncoding.Contains("gzip")) { byte[] bytes = ASCIIEncoding.ASCII.GetBytes(responseBody); response.AddHeader("Content-Encoding", "gzip"); using (GZipStream writer = new GZipStream(response.Body, CompressionMode.Compress)) { writer.Write(bytes, 0, bytes.Length); writer.Flush(); response.Send(); } } else { using (StreamWriter writer = new StreamWriter(response.Body)) { writer.WriteLine(responseBody); writer.Flush(); response.Send(); } }

    Read the article

  • Invoking a function (main()) from a binary file in C

    - by Dhara Darji
    I have simple c program like, my_bin.c: #include <stdio.h> int main() { printf("Success!\n"); return 0; } I compile it with gcc and got executable: my_bin. Now I want to invoke main (or run this my_bin) using another C program. That I did with mmap and function pointer like this: #include <stdio.h> #include <fcntl.h> #include <sys/mman.h> int main() { void (*fun)(); int fd; int *map; fd = open("./my_bin", O_RDONLY); map = mmap(0, 8378, PROT_READ, MAP_SHARED, fd, 0); fun = map; fun(); return 0; } PS: I went through some tutorial, for how to read binary file and execute. But this gives Seg fault, any help appreciated! Thanks!

    Read the article

  • creative way for implementing Data object with it's corespanding buisness logic class in java

    - by ekeren
    I have a class that need to be serialized (for both persistentcy and client-server communication) for simplicity reasons lets call the classes Business a BusinessData and I prefix for their Interfaces. All the getter and setter are delegated from Business class to BusinessData class. I thought about implementing IBusinessData interface that will contain all the getter and setters and IBusiness interface that will extend it. I can either make Business extend BuisnessData so I will not need to implement all getter and setter delegates, or make some abstract class ForwardingBusinessData that will only delegate getter and setters. Any of the above option I loose my hierarchy freedom, does any of you have any creative solution for this problem... I also reviewed DAO pattern: http://java.sun.com/blueprints/patterns/DAO.html

    Read the article

  • Exposing some live data on a website - New to ASP.NET, need guidelines

    - by Carlos
    I have a large .NET based system running within the company intranet, which allows winforms users to see some live calculated numbers and a custom winforms control drawn live (but not real-time). The Forms users can also affect the operation of the system. I would like to just show the live numbers on a website, along with the custom control. Nothing needs to come back from the web user, as the web app is meant to be just for monitoring. All the numbers can be calculated at the server. It's been a long time since I touched ASP.NET, and I need to know how to proceed. What are the steps in building and deploying such a website? Any caveats I need to look out for?

    Read the article

  • JSF Open new window and display bean data

    - by JSFPRINTER
    I am running JSF 2.0 and the latest version of Primefaces 2.2RC1 I believe. I am trying to create a printer friendly window. When the user clicks on a p:commandLink I want a new window to open and display a xhtml file I have named printView.xhtml. Now I can get the window working fine using JavaScript window.open but when I open the new window it will not render any values it just displays everything as #{myBean.value}. Does anyone know how to properly open a window and extend the current scope of the application into that window so I can call all of my managed beans properly and display the values etc. etc.

    Read the article

  • How to handle choice field with JPA 2, Hibernate 3.5

    - by phmr
    I have an entity with Integer attributes that looks like this in proto code: class MyEntity: String name Integer frequency Integer type def getFrequency() def getType() get* accessors return strings according to this table. value(type) HumanReadableString(type) 1 BSD 2 Apache 3 GPL min frequency max frequency HumanReadableString(frequency) 0 1000 rare 1000 2000 frequent 2001 3000 sexy It should be possible to get all possible values that an attribute can take, example: getChoices(MyEntity, "type") returns ("rare", "frequent", "sexy") It should be possible to get the bound value from the string: getValue(MyEntity, "frequency", "sexy") returns (2000,3000)

    Read the article

  • Retrieving data from facebook in a winform

    - by gillyb
    Hey, I understand that using the facebook API I need an api key to connect, but I still don't understand how i would go about doing this, and how can i retrieve information upon users using the API (i'm only interested in retrieving the information that is publicly available e.g: username, birthdate, and other info that a specific user left public) I downloaded the facebook development kit, and tried adding the FacebookService control, but i don't get it... All the examples/samples i found on the internet are older than the version i have and therefore work a little different.. Can someone please post an example of how i would connect, using a certain API key, and retrieve someones public info/public photos (if there are any) ?? Thanks. :)

    Read the article

  • Replacing multiple patterns in a block of data

    - by VikrantY
    Hi All, I need to find the most efficient way of matching multiple regular expressions on a single block of text. To give an example of what I need, consider a block of text: "Hello World what a beautiful day" I want to replace Hello with "Bye" and "World" with Universe. I can always do this in a loop ofcourse, using something like String.replace functions availiable in various languages. However, I could have a huge block of text with multiple string patterns, that I need to match and replace. I was wondering if I can use Regular Expressions to do this efficiently or do I have to use a Parser like LALR. I need to do this in JavaScript, so if anyone knows tools that can get it done, it would be appreciated.

    Read the article

  • API for displaying graphs in a web app?

    - by Rosarch
    I have graphs (nodes/arcs) that I want to display to the user. I need to be able to capture the event of a user clicking on a node. Something like Google Charts API's Simple Org Chart would be great, but it looks like it only supports trees. What other service can I use? Or should I hack something ugly together using Google Charts?

    Read the article

  • how to handle result set data

    - by ashwani66476
    Hello All I am getting lacks of records in my Result Set. My concerns are : How Result Set handle these records internally? and How a programmer can handle those records in batches So that memory problem would not occur.? waiting for your answers .. Many Thanks

    Read the article

  • Insert data in an object to a database.

    - by paul
    I am facing the following design/implementation dilemma. I have a class Customer which is below with getters and setters. I would like to insert the value of the Customer into a "Customer" table of a database. But Customer has an address which is of type "Address". How do I go about inserting this field into the database?(I am using sqlite3). I thought of writing a separate table "Address(customerId,doorNo,city,state,country,pinCode)". But I am having second thoughts about generating the primary key(customerId) which should be same for both the "customer" and "Address" table. Sqlite3 faq states that I can do "Integer Primary Key" to use the field to generate an auto number. But if I do that in customer table, I would have to retrieve the same Id to be used in Address table. This kinda looks wrong to me :-?. There should be an elegant method to solve this. Any ideas would be much appreciated. Thanks in advance. import java.io.*; import java.sql.*; class Customer { private String id; private String name; private Address address; private Connection connection; private ResultSet resultSet; private PreparedStatement preparedStatement; public void insertToDatabase(){ } } class Address{ private String doorNumber; private String streetName; private String cityName; private String districtName; private String stateName; private String countryName; private long pinCode; }

    Read the article

  • SQl Server - Hierarchical Data

    - by JMSA
    I use SQL Server 2000. Suppose I have two tables like the following: Area ---------------------------------- ID| Name | HierarchyLevel ---------------------------------- 1 | World | 1 2 | America| 2 3 | Europe | 2 4 | Africa | 2 5 | USA | 3 and AreaHierarchy ------------------------ ID | ParentID | ChildID ------------------------ 1 | 1 | 2 2 | 1 | 3 3 | 1 | 4 4 | 2 | 5 where AreaHierarchy.ParentID and AreaHierarchy.ChildID are FKs of Area.ID How can I find the nth parent of USA? Is it possible without looping? Probably not.

    Read the article

  • DMX Analysis Services question

    - by user282382
    Hi, I am have two mining models, both are time series. One is [Company_Inputs] and the other is [Booking_Projections]. What I want to do is use EXTEND_MODEL_CASES to join the results of [Company_Inputs] as the extended cases. So basically something like: Select Flattened PredictTimeSeries([Bookings], 1, 6, EXTEND_MODEL_CASES) FROM [Booking_Projections] Natural Prediction Join (Select Flattened PredictTimeSeries([Metric1], 1, 6) From [Company_Inputs]) AS T This code of course doesn't work, but the idea is to use the predictions made from [Company_Inputs] as cases for predicting future values of [Booking_Projections] If anyone has an idea of how I can accomplish this I would appreciate it very much.

    Read the article

  • Is it safe to put reference to current user in User model in Rails?

    - by Art Shayderov
    You know, I think I have to check current user in the model callbacks (like before_update). Rather than rely solely on adding where ('something.user_id = ?', 'current_user.id') in the controllers. I need something like Thread.CurrentPrincipal in .NET Is it safe to put reference to current user in User model? I'm sorry I don't really understand how it works under the hood yet. Or how you do it The Rails way? Sorry if this a silly question.

    Read the article

  • Cleansing string / input in Coldfusion 9

    - by Jakub
    I have been working with Coldfusion 9 lately (background in PHP primarily) and I am scratching my head trying to figure out how to 'clean/sanitize' input / string that is user submitted. I want to make it HTMLSAFE, eliminate any javascript, or SQL query injection, the usual. I am hoping I've overlooked some kind of function that already comes with CF9. Can someone point me in the proper direction?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 447 448 449 450 451 452 453 454 455 456 457 458  | Next Page >