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• How to set up a load/stress test for a web site?

  - by Ryan

  I've been tasked with stress/load testing our company web site out of the blue and know nothing about doing so. Every search I make on google for "how to load test a web site" just comes back with various companies and software to physically do the load testing. For now I'm more interested in how to actually go about setting up a load test like what I should take into account prior to load testing, what pages within my site I should be testing load against and what things I'm going to want to monitor when doing the test. Our web site is on a multi-tier system complete with a separate database server (IIS 7 Web Server, SQL Server 2000 db). I imagine I'd want to monitor both the web server and the database server for testing load however when setting up scenarios to load test the web server I'd have to use pages that query the database to see any load on the database server at the same time. Are web servers and database servers generally tested simultaneously or are they done as separate tests? As you can see I'm pretty clueless as to the whole operation so any incite as to how to go about this would be very helpful. FYI I have been tinkering with Pylot and was able to create and run a scenario against our site but I'm not sure what I should be looking for in the results or if the scenario I created is even a scenario worth measuring for our site. Thanks in advance.

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• Does Windows 8 Need New, Specialized Drivers?

  - by Synetech

  It seems like an obvious question, but I’m having a difficult time finding out if Windows 8, with all its changes, will require new, specialized drivers. I see that a lot of manufacturers have started releasing Windows 8-specific drivers for their hardware, but what about those that are not, will Windows XP or 7 drivers work or have they changed the driver/system/security architecture again, thus requiring new drivers? The closest thing I could find to an answer was a thread in which it was mentioned that the display driver model was again updated, thus requiring new display drivers, but not much else (e.g., audio cards, printers, chipsets, etc.)

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• In a php script making /coderoot refer to /var/webroot/coderoot?

  - by Josh

  We are migrating a server and have modified the architecture slightly so that instead of /var/coderoot we now have /var/webroot/coderoot - I realize I could do a scripted find and replace, but I would rather have full unmodified reverse compatibility, or if that's unreasonable lets just say for theories sake. I tried using a symmlink ln -s /var/coderoot /var/webroot/coderoot but attempting to include a file in the code root using /var/coderoot/file does not work. I also tried using mod_alias with ScriptAlias and Alias. Neither worked. Is there anyway to do this?

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• Complex orderby question (entity framework)

  - by PFranchise

  Ok, so I will start by saying that I am new to all this stuff, and doing my best to work on this project. I have an employee object, that contains a supervisor field. When someone enters a search on my page, a datagrid displays employees whose name match the search. But, I need it to display all employees that report to them and a third tier of employees that report to the original employee's underlings. I only need three tiers. To make this easier, employees only come in 3 ranks, so if rank==3, that employee is not in charge of others. I imagine the best method of retrieving all these employees from my employee table would be something like from employee in context.employees where employee.name == search || employee.boss.name == search || employee.boss.boss.name == search But I am not sure how to make the orderby appear the way I want to. I need it to display in tiers. So, it will look like: Big Boss Boss underling underling Boss underling Boss Boss Big Boss Like I said, there might be an easier way to approach this whole issue, and if there is, I am all ears. Any advice you can give would be HIGHLY appreciated.

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• Dividing numbers between rows in MySQL + PHP

  - by André Figueira

  Hi I am working on a kind of raffle system which divides 1 million random numbers into an x amount of tickets, e.g. 1 million random numbers to 10,000 tickets. Each ticket is a row in a database, we then have another table ticket numbers in which i need to give 100 numbers to each ticket they are related by the ticket id. So at the moment this is my code: //Amount of the 1 million tickets divided to the tickets $numbersPerTickets = $_POST['numbersPerTicket']; //The total cost of the property $propertyPrice = $_POST['propertyPrice']; //The total amount of tickets $totalTickets = NUMBER_CIELING / $numbersPerTickets; //The ticket price $ticketPrice = $propertyPrice / $totalTickets; //Generate array with random numbers up to 999,999 $randomTicketNumbers = createTicketNumbers(); //Creation loop counter $ticketCreationCount = 1; //Loop and create each ticket while($ticketCreationCount <= $totalTickets) { //Create a padded ticket number $ticketNumber = str_pad($ticketCreationCount, 6, 0, STR_PAD_LEFT); $query = ' INSERT INTO tickets( propertyID, ticketNumber, price ) VALUES( "'.$propertyID.'", "'.$ticketNumber.'", "'.$ticketPrice.'" ) '; $db->query($query); //Get the ID of the inserted ticket to use to insert the ticket numbers $ticketID = $db->insert_id; $loopBreak = $numbersPerTickets; $addedNumberCount = 1; foreach($randomTicketNumbers as $key => $value) { $query = ' INSERT INTO ticketNumbers( ticketID, number ) VALUES( "'.$ticketID.'", "'.$value.'" ) '; $db->query($query); unset($randomTicketNumbers[$key]); if($addedNumberCount == $loopBreak){ break; }else{ $addedNumberCount++; } } $ticketCreationCount++; } But this isn't working it adds the right amount of tickets, which in the case for testing is 10,000 but then adds far too many ticket numbers, it ends up exceeding the million numbers in the random tickets array, The random tickets array is just a simple 1 tier array with 1 million numbers sorted randomly.

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• List<T> paging asp.net

  - by user1397978

  Using a three-tier architecture, I have a list of objects List<object> careerList = new List<object>(); ModuleDTO module = new ModuleDTO(); careerList = module.getDegreeCodeByQualification(qualificationCode); which I then add to a gridview like so: gridViewMaster.DataSource = careerList; gridViewMaster.DataBind(); What I'd like to do is then enable paging on the gridview. My gridview so far is: <asp:GridView ID="gridViewMaster" runat="server" AutoGenerateColumns="False" GridLines="None" BorderWidth="1px" CellPadding="2" DataKeyNames="Grouping" ForeColor="Black" onrowdatabound="gridViewMaster_RowDataBound" CssClass="mGrid" PagerStyle-CssClass="pgr" AlternatingRowStyle-CssClass="alt" OnPageIndexChanging="gridView_PageIndexChanging" AllowPaging="True" > Is it possible to do enable paging on a list's without having to change that list to a Datatable or Dataview? If there is a way, this would help a lot. So far my events are as follows: protected void gridView_PageIndexChanging(object sender, GridViewPageEventArgs e) { gridViewMaster.PageIndex = e.NewPageIndex; List<object> careerList = new List<object>(); ModuleDTO module = new ModuleDTO(); careerList = module.getDegreeCodeByQualification(qualificationCode); ModalProgress.Show(); System.Threading.Thread.Sleep(1000); JobPanel.Visible = true; gridViewMaster.DataSource = careerList.Distinct(); gridViewMaster.DataBind(); } Someone PLEASE HELP ME!!! Thank you

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• Spring MVC: Where to place validation and how to validation entity references.

  - by arrages

  Let's say I have the following command bean for creating a user: public class CreateUserCommand { private String userName; private String email; private Integer occupationId; pirvate Integer countryId; } occupationId and countryId are drop down selected values on the form. They map to an entity in the database (Occupation, Country). This command object is going to be fed to a service facade like so: userServiceFacade.createUser(CreateUserCommand command); This facade will construct a user entity to be sent to the actual service. So I suppose that in the facade layer I will have to make several dao calls to map all the lookup properties of the User entity. Based on this what is the best strategy to validate that occupationId and countryId map to real entities? Where is the best place to perform this validation? There is the spring validator but I am not sure this is the best place for this, for one I am wary of this method as validation is tied to the web tier, but also that means I would need to make the dao calls in the validator for validation but I would need to call the dao's in the facade layer again when the command - entity translation occurs. Is there anything I can do better? Thanks.

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• Optimization in Common Decalaration

  - by Pratik

  Its a 3-tier ASP.NET Website Project In Data Layer there is class "Common Decalaration" in which lot of common things are mentioned. Something this way : public class CommonDeclartion { #region Common Messages public const string RECORD_INSERT_MSG = "Record Inserted Successfully "; public const string RECORD_UPDATE_MSG = "Record Updated Successfully"; public const string RECORD_DELETE_MSG = "Record Deleted Successfully"; public const string ERROR_MSG = "Error Ocuured while Perfoming This Action."; public const string UserID_Incorrect = "Please Enter The Correct User ID."; public const string RECORD_ALREADY_EXIT = "Record Already Exit"; public const string NO_RECORD = "No Record found."; #endregion } Can this be more optimized in terms of : 1.Perfomance 2.Security(if any) 3.Code Readablity or Reusablity I thought of using enum but can't figure that out : enum CommonMessages { RECORD_INSERT_MSG "Record Inserted Successfully.", RECORD_UPDATE_MSG "Record Updated Successfully.", RECORD_DELETE_MSG "Record Deleted Successfully.", ERROR_MSG "Error Ocuured while Perfoming This Action.", UserID_Incorrect "Please Enter The Correct User ID.", RECORD_ALREADY_EXIT "Record Already Exit.", NO_RECORD "No Record found.", } or else should keep them in some collections like dictionary/NameValueCollection or so or i have to keep them in XML in form of key/value pair and reterive from it ? What can be better way keeping in mind 1.Perfomance 2.Security(if any) 3.Code Readablity or Reusablity

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• How do I scale EC2 and push out code / data to my instances?

  - by chris

  Unfortunately I only have a limited knowledge of server architecture, I come from a development background. I am looking to ensure my new app can scale properly using EC2. I currently have a T1.micro for development running Windows with SQL server 2008. The system allows students to come to our site to search for a mentor, update their profile with pictures and employment history etc. Roughly the same sort of work as a LinkedIn profile. I need this to be able to scale very quickly without wasted resources. I understand the following is important. Separation of data, application etc. I will achieve this I think by hosting images using S3, Database instance via RDS and upgrade the EC2 instance. My main question is: How do I push data / code out to multiple ec2 / RDS instances seamlessly?

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• Getting Started: Silverlight 4 Business Application

  - by Eric J.

  With the arrival of VS 2010 and Silverlight 4, I decided it's time to look into Silverlight and understand how to build a 3-Tier business application. After several hours of searching for and reading documentation and tutorials, I'm thoroughly confused (and that doesn't happen easily). Here are some specific points I don't understand. I welcome guidance on any of them, and also would appreciate any references to a really good tutorial. Brad Abrahm's What is a .NET RIA services (written for Silverlight 3) seemed very promising, until I realized I don't have System.Web.Ria.dll on my system. Am I missing an optional download? Was this rolled into another DLL for Silverlight 4? Did this go away in favor of something else in Silverlight 4? This recent blog says to start from a Silverlight Business Application, remove unwanted stuff, create a WCF RIA services Class Library project, and copy files and references from the Business Application to the WCF RIA services project, while manually updating resource references (perhaps bug in B2 compiler). Is this really the right road to go down? It seems very clumsy. My requirements are to perform very simple CRUD on straightforward business objects. I'm looking forward to suggestions on how to do that the Silverlight 4 way.

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• How can I upgrade from Windows 8 x32 to x64 fastest & easiest?

  - by parkviewK

  I was upgrading the hardware in a family member's computer and purchased the Windows 8 upgrade for $40 from their website. Not thinking, after I installed it I realized I now have 32bit Windows on this 64bit capable machine. Did some research and it appears that the upgrade assistant just gives you whatever architecture you were uprgading from (windows 7 32bit). Question is, what is my best option here? I have already purchased a key, will this work on x64? I'm considering installing Windows 8 Preview x64 and upgrading from there, but not sure if that will work or if it will make me purchase it again.

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• Intercepting LAN network traffic via WiFi

  - by user1613655

  Let's get straight to the point. This is my fictive network architecture: My question is: Would it be possible for Laptop B to intercept traffic sent and received by Laptop A? Please note that B only has WiFi access and no physical control over Router B. Furthermore, Router A and B create different wireless networks with different encryption keys. If both shared the same wireless network or Laptop B had LAN-access to Router B, the answer would be trivial, but I'm not sure how the answer turns out in this scenario :-/ Thanks for your valuable help!

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• Help me refactor my World Cup Challenge Script

  - by kylemac

  I am setting up a World Cup Challenge between some friends, and decided to practice my Ruby and write a small script to automate the process. The Problem: 32 World Cup qualifiers split into 4 tiers by their Fifa ranking 8 entries Each entry is assigned 1 random team per tier Winner takes all :-) I wrote something that suffices yet is admittedly brute force. But, in my attempt to improve my Ruby, I acknowlege that this code isn't the most elegant solution around - So I turn to you, the experts, to show me the way. It may be more clear to check out this gist - https://gist.github.com/91e1f1c392bed8074531 My Current (poor) solution: require 'yaml' @teams = YAML::load(File.open('teams.yaml')) @players = %w[Player1 Player2 Player3 Player4 Player5 Player6 Player7 Player8] results = Hash.new players = @players.sort_by{rand} players.each_with_index do |p, i| results[p] = Array[@teams['teir_one'][i]] end second = @players.sort_by{rand} second.each_with_index do |p, i| results[p] << @teams['teir_two'][i] end third = @players.sort_by{rand} third.each_with_index do |p, i| results[p] << @teams['teir_three'][i] end fourth = @players.sort_by{rand} fourth.each_with_index do |p, i| results[p] << @teams['teir_four'][i] end p results I am sure there is a better way to iterate through the tiers, and duplicating the @players object ( dup() or clone() maybe?) So from one Cup Fan to another, help me out.

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• Looking for a VPN server that fits my needs

  - by BCS

  This question (and some more research) has revealed that OpenVPN isn't for me. So, what are my other options? In particular things I need/want (most important first) are: A server daemon that runs on Linux without kernel modules Clients work from behind NATs and Firewalls. Free/FOSS Support for PPTP, L2TP or L2TP/IPSec PSK/CRT A architecture that makes all accesses equal: if the server is to have access to the VPN, then it must be a client. Just like everyone else. Minimal configuration/state. The first 3 are must haves and the last is a nice to have. The rest I could live without, but then again I could also live with nothing.

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• How do software projects go over budget and under-deliver?

  - by Carlos

  I've come across this story quite a few times here in the UK: NHS Computer System Summary: We're spunking £12 Billion on some health software with barely anything working. I was sitting the office discussing this with my colleagues, and we had a little think about. From what I can see, all the NHS needs is a database + middle tier of drugs/hospitals/patients/prescriptions objects, and various GUIs for doctors and nurses to look at. You'd also need to think about security and scalability. And you'd need to sit around a hospital/pharmacy/GPs office for a bit to figure out what they need. But, all told, I'd say I could knock together something with that kind of structure in a couple of days, and maybe throw in a month or two to make it work in scale. If I had a few million quid, I could probably hire some really excellent designers to make a maintainable codebase, and also buy appropriate hardware to run the system on. I hate to trivialize something that seems to have caused to much trouble, but to me it looks like just a big distributed CRUD + UI system. So how on earth did this project bloat to £12B without producing much useful software? As I don't think the software sounds so complicated, I can only imagine that something about how it was organised caused this mess. Is it outsourcing that's the problem? Is it not getting the software designers to understand the medical business that caused it? What are your experiences with projects gone over budget, under delivered? What are best practices for large projects? Have you ever worked on such a project?

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• Windows log file monitor that supports custom events (eg. sending an email when it detects the string "ERROR")

  - by ilitirit

  I know this question has been asked several times before but I can't seem to find a solution for my requirements. I currently use BareTail, which works wonderfully except that it doesn't support custom events besides line highlighting. I'm also trying TailForWin32. It has a SMTP plugin but it seems to be in beta status, and the highlighting seems limited. It also doesn't handle rolling log files very well (a blocking dialog box pops up, whereas BareTail just rolls over naturally). All I really need is something like BareTail that supports custom events. First prize would be a tool with a plugin-based architecture so I can use my own messaging plugins, but anything that supports SMTP mail would be fine as well.

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• Entity Framework: Detect DBSchema for licensing

  - by Program.X

  We're working on a product that may or may not have differing license schema for different databases. In particular, a lower-tier product would run on SQLExpress, but we don't want the end user to be able to use a "full-fat" SQL install - benefiting from the price cut. Clearly this must also be the case for other DBs, so Oracle may command a higher price than SQL, for instance (hypothetically). We're using Entity Framework. Obviously this hides all the neatness of accessing the core schema and using sp_version or whatever it is. We'd rather not pre-load the condition by running a series of SQL commands (one for each platform) and see what comes back, as this would limit our DB options. But if necassary, we're prepared to do it. So, is it possible to get this using EF itself? DBContext.COnnection.ServerVersion only returns something like "9.00.1234" (for SQL Server 2005). I would assume (though haven't yet checked - need to install an instance) SQLExpress would return something similar - "pretending" it is full-fat. Obviously, we have no Oracle/MySQL/etc. instance so can't establish whether that returns text "Oracle" or whatever.

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• Are workflows good for web service business logic?

  - by JL

  I have a series of complex web services that are getting used in my SOA application. I am generally happy with the overall design of the application, but as the complexity grows, I was wondering if Windows Workflow might be the way to go. My motivations for this are that you can get a graphic representation of the applications functionality, so it would be easier to maintain the code by its business function, rather than what I have now ( a standard 3 tier class library structure). My concerns are: I would be inducing an abstraction in my code, and I don't want to spend time having to deal with possible WF quirks or bugs. I've never worked with WF, is it a solid technology? I don't want to hit any WF limitations that prevent me from developing my solution. Is a WF even the right solution for the task? Simply put I am considering writing my next web service in this app to call a WF, and in this work flow manage the tasks the web service needs to carry out. I think it will be much neater and easier to maintain than a regular c# class library (maintainable by namespaces, classes ). Do you think this is the right thing to do? I'm hoping for positive feedback on WF (.net 4), but brutal honestly at the end of the day would help more. Thanks

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• Central Storage for windows user accounts homedirs .. hardware/software needed?

  - by mtkoan

  We have ~120+ users in our network, and are endeavoring to centralize logon authentication and home directory storage server-side. Most of the users are Windows 2000/XP machines, and a few running Mac OS X. Ideally the solution will be open-source-- can this all be managed from a Linux server running LDAP and Samba? Or would a hacked-NAS Box with a FreeNAS or similar suffice? Or is Micro$oft's Active Directory really the preference here. Is it viable to store PST files on this server for users to read from and write to? They are very large ~1.5gb. We have no mail server (or money) capable of Exchange or IMAP, only an old POP3. What kind of hardware horsepower and network architecture should we have for this kind of thing?

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• Can i use a Windows 2008 r2 Cluster for file redundancy

  - by JERiv

  I'm researching a sever clustering architecture as a redundancy and backup solution for a client, and something that isn't made clear is whether or not i can use server clustering to replace a file server with backup solution. Forgive my Elementary understanding of server clustering but supposing: 2 Sites (NJ, CA) Identical Servers at each site setup as a Remote Site Cluster nodes with Windows Enterprise server 2008 r2 Services: File, Terminal, AD, and maybe DNS Will the following will be true: Files (including data drives) will be synced between the two servers eliminating the need for third party backup/mirroring software to sync/backup files. Also supposing i use roaming profiles w/ folder redirection; How will client computer in the WAN access their data through the cluster (i.e. will they automatically choose the best route)

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• How much faster is a 64bit CPU than 32bit CPU? [closed]

  - by W.N.

  I just need the result in theory. I'm not an expert in computer architecture, just a software developer. Most of my friends think 64bit-CPU is 2 times faster than 32bit-CPU. But I think 64-CPU is 2 ^ 2 = 4 times faster than 32bit-CPU (in theory). Which is the right answer to this question? And, if there were 128bit-CPU, how many times would it faster than a 32bit-CPU? PS: I searched with Google, and found a link that referred to benchmarks that supported my answer. I've seen a benchmark where 64bit was 4x faster but that was with a particular encryption where the extra registers available made the difference

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• Nullable object must have a value. VB.NET

  - by Glenn05

  I need help. I'm having problem in my program. This is my code on my Business logic layer. Function Load_ItemDetails(ByVal ItemID As String) As Items Dim objItemEnt As New tblitem Dim objitem As New Items Try Using da = New DataAccess objItemEnt = da.Load_ItemDetails(ItemID) With objitem .ItemCode = objItemEnt.ItemCode .ItemName = objItemEnt.ItemName .Description = objItemEnt.Description .NameofType = objItemEnt.NameofType .TypeofPricing = objItemEnt.TypeofPricing .OnStock = objItemEnt.OnStock .ItemPrice = objItemEnt.ItemPrice .DateModified = objItemEnt.DateModified End With Return objitem End Using Catch ex As Exception Throw End Try End Function This code is for my data access layer. Public Function Load_ItemDetails(ByVal ItemCode As String) Dim objitem As New tblitem Try Using entItem = New DAL.systemdbEntities1 Dim qryUsers = From p In entItem.tblitems Where p.ItemCode = ItemCode Select p Dim luser As List(Of tblitem) = qryUsers.ToList If luser.Count > 0 Then Return luser.First Else Return objitem End If End Using Catch ex As Exception Throw End Try End Function` For my Presentation layer: Private Sub Load_Item_Detail(ByVal ItemCode As String) objItem = New Items Using objLogic = New LogicalLayer objItem = objLogic.Load_ItemDetails(ItemCode) With objItem Me.ItemCodetxt.Text = .ItemCode Me.ItemNametxt.Text = .ItemName Me.ItemDesctxt.Text = .Description Me.ItemTypetxt.Text = .NameofType Me.ItemPricetxt.Text = .TypeofPricing Me.ItemOnstocktxt.Text = CStr(.OnStock) Me.ItemPricetxt.Text = CStr(.ItemPrice) Me.TextBox1.Text = CStr(.DateModified) Me.ItemCodetxt.Tag = .ItemCode End With End Using End Sub` and after I run, I get this error Nullable object must have a value help me. I'm stuck. I don't know what to do guys. I new in n tier architecture.

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• Implementing search functionality with multiple optional parameters against database table.

  - by quarkX

  Hello, I would like to check if there is a preferred design pattern for implementing search functionality with multiple optional parameters against database table where the access to the database should be only via stored procedures. The targeted platform is .Net with SQL 2005, 2008 backend, but I think this is pretty generic problem. For example, we have customer table and we want to provide search functionality to the UI for different parameters, like customer Type, customer State, customer Zip, etc., and all of them are optional and can be selected in any combinations. In other words, the user can search by customerType only or by customerType, customerZIp or any other possible combinations. There are several available design approaches, but all of them have some disadvantages and I would like to ask if there is a preferred design among them or if there is another approach. Generate sql where clause sql statement dynamically in the business tier, based on the search request from the UI, and pass it to a stored procedure as parameter. Something like @Where = ‘where CustomerZip = 111111’ Inside the stored procedure generate dynamic sql statement and execute it with sp_executesql. Disadvantage: dynamic sql, sql injection Implement a stored procedure with multiple input parameters, representing the search fields from the UI, and use the following construction for selecting the records only for the requested fields in the where statement. WHERE (CustomerType = @CustomerType OR @CustomerType is null ) AND (CustomerZip = @CustomerZip OR @CustomerZip is null ) AND ………………………………………… Disadvantage: possible performance issue for the sql. 3.Implement separate stored procedure for each search parameter combinations. Disadvantage: The number of stored procedures will increase rapidly with the increase of the search parameters, repeated code.

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• Need a solution to store images (1 billion, 1000,000,000) which users will upload to a website via php or javascript upload [on hold]

  - by wish_you_all_peace

  I need a solution to store images (1 billion) which users will upload to a website via PHP or Javascript upload (website will have 1 billion page views a month using Linux Debian distros) assuming 20 photos per user maximum (10 thumbnails of size 90px by 90px and 10 large, script resized images of having maximum width 500px or maximum height 500px depending on shape of image, meaning square, rectangle, horizontal, vertical etc). Assume this to be a LEMP-stack (Linux Nginx MySQL PHP) social-media or social-matchmaking type application whose content will be text and images. Since everyone knows storing tons of images (website users uploaded images in this case) are bad inside a single directory or NFS etc, please explain all the details about the architecture and configuration of the entire setup of storage solution, to store 1 billion images on any method you recommend (no third-party cloud storage like S3 etc. It has to be within the private data center using our own hardware and resources.). The solution has to include both the storage solution and organizing the images uploaded by users. How will we organize the users images if a single user will not have more than 20 images (10 thumbs and 10 large of having either width or height 500px)? Please consider that this has to be organized in a structural way so we can fetch a single user's images via PHP/Javascript or API programmatically through some type of user's unique identifier(s).

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• Control to Control Binding in WPF/Silverlight

  - by psheriff

  In the past if you had two controls that you needed to work together, you would have to write code. For example, if you want a label control to display any text a user typed into a text box you would write code to do that. If you want turn off a set of controls when a user checks a check box, you would also have to write code. However, with XAML, these operations become very easy to do. Bind Text Box to Text Block As a basic example of this functionality, let’s bind a TextBlock control to a TextBox. When the user types into a TextBox the value typed in will show up in the TextBlock control as well. To try this out, create a new Silverlight or WPF application in Visual Studio. On the main window or user control type in the following XAML. <StackPanel>  <TextBox Margin="10" x:Name="txtData" />  <TextBlock Margin="10"              Text="{Binding ElementName=txtData,                             Path=Text}" /></StackPanel> Now run the application and type into the TextBox control. As you type you will see the data you type also appear in the TextBlock control. The {Binding} markup extension is responsible for this behavior. You set the ElementName attribute of the Binding markup to the name of the control that you wish to bind to. You then set the Path attribute to the name of the property of that control you wish to bind to. That’s all there is to it! Bind the IsEnabled Property Now let’s apply this concept to something that you might use in a business application. Consider the following two screen shots. The idea is that if the Add Benefits check box is un-checked, then the IsEnabled property of the three “Benefits” check boxes will be set to false (Figure 1). If the Add Benefits check box is checked, then the IsEnabled property of the “Benefits” check boxes will be set to true (Figure 2). Figure 1: Uncheck Add Benefits and the Benefits will be disabled. Figure 2: Check Add Benefits and the Benefits will be enabled. To accomplish this, you would write XAML to bind to each of the check boxes in the “Benefits To Add” section to the check box named chkBenefits. Below is a fragment of the XAML code that would be used. <CheckBox x:Name="chkBenefits" /> <CheckBox Content="401k"           IsEnabled="{Binding ElementName=chkBenefits,                               Path=IsChecked}" /> Since the IsEnabled property is a boolean type and the IsChecked property is also a boolean type, you can bind these two together. If they were different types, or if you needed them to set the IsEnabled property to the inverse of the IsChecked property then you would need to use a ValueConverter class. SummaryOnce you understand the basics of data binding in XAML, you can eliminate a lot code. Connecting controls together is as easy as just setting the ElementName and Path properties of the Binding markup extension. NOTE: You can download the complete sample code at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "SL – Basic Control Binding" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

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