Search Results

Search found 24382 results on 976 pages for 'tutor process procedure f'.

Page 650/976 | < Previous Page | 646 647 648 649 650 651 652 653 654 655 656 657  | Next Page >

  • How to ensure DB security for a Windows Forms application?

    - by Vilx-
    The basic setup is classic - you're creating a Windows Forms application that connects to a DB and does all kinds of enterprise-y stuff. Naturally, such an application will have many users with different access rights in the DB, and each with their own login name and password. So how do you implement this? One way is to create a DB login for every application user, but that's a pretty serious thing to do, which even requires admin rights on the DB server, etc. If the DB server hosts several applications, the admins are quite likely not to be happy with this. In the web world typically one creates his own "Users" table which contains all the necessary info, and uses one fixed DB login for all interaction. That is all nice for a web app, but a windows forms can't hide this master login information, negating security altogether. (It can try to hide, but all such attempts are easily broken with a bit of effort). So... is there some middle way? Perhaps logging in with a fixed login, and then elevating priviledges from a special stored procedure which checks the username and password?

    Read the article

  • Rewriting a for loop in pure NumPy to decrease execution time

    - by Statto
    I recently asked about trying to optimise a Python loop for a scientific application, and received an excellent, smart way of recoding it within NumPy which reduced execution time by a factor of around 100 for me! However, calculation of the B value is actually nested within a few other loops, because it is evaluated at a regular grid of positions. Is there a similarly smart NumPy rewrite to shave time off this procedure? I suspect the performance gain for this part would be less marked, and the disadvantages would presumably be that it would not be possible to report back to the user on the progress of the calculation, that the results could not be written to the output file until the end of the calculation, and possibly that doing this in one enormous step would have memory implications? Is it possible to circumvent any of these? import numpy as np import time def reshape_vector(v): b = np.empty((3,1)) for i in range(3): b[i][0] = v[i] return b def unit_vectors(r): return r / np.sqrt((r*r).sum(0)) def calculate_dipole(mu, r_i, mom_i): relative = mu - r_i r_unit = unit_vectors(relative) A = 1e-7 num = A*(3*np.sum(mom_i*r_unit, 0)*r_unit - mom_i) den = np.sqrt(np.sum(relative*relative, 0))**3 B = np.sum(num/den, 1) return B N = 20000 # number of dipoles r_i = np.random.random((3,N)) # positions of dipoles mom_i = np.random.random((3,N)) # moments of dipoles a = np.random.random((3,3)) # three basis vectors for this crystal n = [10,10,10] # points at which to evaluate sum gamma_mu = 135.5 # a constant t_start = time.clock() for i in range(n[0]): r_frac_x = np.float(i)/np.float(n[0]) r_test_x = r_frac_x * a[0] for j in range(n[1]): r_frac_y = np.float(j)/np.float(n[1]) r_test_y = r_frac_y * a[1] for k in range(n[2]): r_frac_z = np.float(k)/np.float(n[2]) r_test = r_test_x +r_test_y + r_frac_z * a[2] r_test_fast = reshape_vector(r_test) B = calculate_dipole(r_test_fast, r_i, mom_i) omega = gamma_mu*np.sqrt(np.dot(B,B)) # write r_test, B and omega to a file frac_done = np.float(i+1)/(n[0]+1) t_elapsed = (time.clock()-t_start) t_remain = (1-frac_done)*t_elapsed/frac_done print frac_done*100,'% done in',t_elapsed/60.,'minutes...approximately',t_remain/60.,'minutes remaining'

    Read the article

  • What's the most DRY-appropriate way to execute an SQL command?

    - by Sean U
    I'm looking to figure out the best way to execute a database query using the least amount of boilerplate code. The method suggested in the SqlCommand documentation: private static void ReadOrderData(string connectionString) { string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;"; using (SqlConnection connection = new SqlConnection(connectionString)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); try { while (reader.Read()) { Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1])); } } finally { reader.Close(); } } } mostly consists of code that would have to be repeated in every method that interacts with the database. I'm already in the habit of factoring out the establishment of a connection, which would yield code more like the following. (I'm also modifying it so that it returns data, in order to make the example a bit less trivial.) private SQLConnection CreateConnection() { var connection = new SqlConnection(_connectionString); connection.Open(); return connection; } private List<int> ReadOrderData() { using(var connection = CreateConnection()) using(var command = connection.CreateCommand()) { command.CommandText = "SELECT OrderID FROM dbo.Orders;"; using(var reader = command.ExecuteReader()) { var results = new List<int>(); while(reader.Read()) results.Add(reader.GetInt32(0)); return results; } } } That's an improvement, but there's still enough boilerplate to nag at me. Can this be reduced further? In particular, I'd like to do something about the first two lines of the procedure. I don't feel like the method should be in charge of creating the SqlCommand. It's a tiny piece of repetition as it is in the example, but it seems to grow if transactions are being managed manually or timeouts are being altered or anything like that.

    Read the article

  • delphi app freezes whole win7 system

    - by avar
    Hello i have a simple program that sorts a text file according to length of words per line this program works without problems in my xp based old machine now i run this program on my new win7/intel core i5 machine, it freezes whole system and back normal after it finishes it's work. i'v invastigated the code and found the line causing the freeze it was this specific line... caption := IntToStr(i) + '..' + IntTostr(ii); i'v changed it to caption := IntTostr(ii); //slow rate change and there is no freeze and then i'v changed it to caption := IntTostr(i); //fast rate change and it freeze again my main complete procedure code is var tword : widestring; i,ii,li : integer; begin tntlistbox1.items.LoadFromFile('d:\new folder\ch.txt'); tntlistbox2.items.LoadFromFile('d:\new folder\uy.txt'); For ii := 15 Downto 1 Do //slow change Begin For I := 0 To TntListBox1.items.Count - 1 Do //very fast change Begin caption := IntToStr(i) + '..' + IntTostr(ii); //problemetic line tword := TntListBox1.items[i]; LI := Length(tword); If lI = ii Then Begin tntlistbox3.items.Add(Trim(tntlistbox1.Items[i])); tntlistbox4.items.Add(Trim(tntlistbox2.Items[i])); End; End; End; end; any idea why ? and how to fix it? i use delphi 2007/win32

    Read the article

  • Register new memer for vBulletin via Mobile API

    - by Nikolay Stariradeff
    I'm trying to use the vBulletin REST Mobile API to simply register. The sourced are installed on my local machine and according the documentation https://www.vbulletin.com/forum/content.php/393-User-Registration-Process-Mobile-API This procedure should not be so hard, especially without humanity and COPPA authentication. However I've stacked! The method definition describes "addnewmember" clear, so I've generated a test link, which should do the job. https://www.vbulletin.com/forum/content.php/365-User-Related-Methods The link is: .../forum/api.php?&api_m=register_addmember&api_c=1&api_s=76ec9eec61e7fdfef2f3feee28d5f392&api_sig=8fe54313b333cc0fef4ddd8e398b5c80&api_v=6&agree=1&username=testuser&email=XXXXXX%40gmail.com&emailconfirm=XXXXX%40gmail.com&password=12345678&passwordconfirm=12345678 As a response I get: register_not_agreed The Docs: register_not_agreed The agree parameter should be set to 1. Which is also clear - agree parameter was not there. Here comes the funny part - In the API-Log I can see that the 'agree' parameter is correctly passed *1 test_client Gast 13:23, 18.06.2012 register_addmember Array ( [api_m] = register_addmember [api_c] = 1 [api_s] = 76ec9eec61e7fdfef2f3feee28d5f392 [api_sig] = 8fe54313b333cc0fef4ddd8e398b5c80 [api_v] = 6 [agree] = 1 [username] = testuser [email] = ....* Is there anybody with experience with the Mobile API that could help?

    Read the article

  • vectorizing loops in Matlab - performance issues

    - by Gacek
    This question is related to these two: http://stackoverflow.com/questions/2867901/introduction-to-vectorizing-in-matlab-any-good-tutorials http://stackoverflow.com/questions/2561617/filter-that-uses-elements-from-two-arrays-at-the-same-time Basing on the tutorials I read, I was trying to vectorize some procedure that takes really a lot of time. I've rewritten this: function B = bfltGray(A,w,sigma_r) dim = size(A); B = zeros(dim); for i = 1:dim(1) for j = 1:dim(2) % Extract local region. iMin = max(i-w,1); iMax = min(i+w,dim(1)); jMin = max(j-w,1); jMax = min(j+w,dim(2)); I = A(iMin:iMax,jMin:jMax); % Compute Gaussian intensity weights. F = exp(-0.5*(abs(I-A(i,j))/sigma_r).^2); B(i,j) = sum(F(:).*I(:))/sum(F(:)); end end into this: function B = rngVect(A, w, sigma) W = 2*w+1; I = padarray(A, [w,w],'symmetric'); I = im2col(I, [W,W]); H = exp(-0.5*(abs(I-repmat(A(:)', size(I,1),1))/sigma).^2); B = reshape(sum(H.*I,1)./sum(H,1), size(A, 1), []); But this version seems to be as slow as the first one, but in addition it uses a lot of memory and sometimes causes memory problems. I suppose I've made something wrong. Probably some logic mistake regarding vectorizing. Well, in fact I'm not surprised - this method creates really big matrices and probably the computations are proportionally longer. I have also tried to write it using nlfilter (similar to the second solution given by Jonas) but it seems to be hard since I use Matlab 6.5 (R13) (there are no sophisticated function handles available). So once again, I'm asking not for ready solution, but for some ideas that would help me to solve this in reasonable time. Maybe you will point me what I did wrong.

    Read the article

  • bidirectional OneToOne Mapping : From Entity to subclass and from superclass to Entity?

    - by Teocali
    I'm trying to establish a tricky bidirectional OneToOne mapping in hibernate. I got the following classes : @Entity @Inheritance(strategy = InheritanceType.JOINED) public class Parent { @OneToOne private AnotherEntity anotherEntity; } @Entity public class Child1 extends Parent{} @Entity public class Child2 extends Parent{} @Entity public class AnotherEntity { @OneToOne(mappedBy = "anotherEntity") private Child1 child1; @OneToOne(mappedBy = "anotherEntity") private Child1 child2; } The problem here is when I'm launching the application : I got the following message : org.hibernate.MappingException: property [anotherEntity] not found on entity [Child1] at org.hibernate.mapping.PersistentClass.getRecursiveProperty(PersistentClass.java:429) at org.hibernate.mapping.PersistentClass.getReferencedProperty(PersistentClass.java:369) at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1614) at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1362) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1727) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778) at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:189) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:350) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:335) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:567) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464) at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:631) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:588) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:645) at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:508) at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:449) at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:133) at javax.servlet.GenericServlet.init(GenericServlet.java:160) at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1266) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1185) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1080) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5015) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5302) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615) at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:962) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:536) at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1471) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:301) at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:836) at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:761) at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1436) at org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:673) at org.apache.catalina.manager.ManagerServlet.doPut(ManagerServlet.java:431) at javax.servlet.http.HttpServlet.service(HttpServlet.java:644) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:581) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) One obvious solution would be to move the anotherEntity field to Child1 and Child2, but it would mean lose the link from Parent to AnotherEntity. Any help welcome.

    Read the article

  • [C#][Design] Appropriate programming design questions.

    - by Edward
    I have a few questions on good programming design. I'm going to first describe the project I'm building so you are better equipped to help me out. I am coding a Remote Assistance Tool similar to TeamViewer, Microsoft Remote Desktop, CrossLoop. It will incorporate concepts like UDP networking (using Lidgren networking library), NAT traversal (since many computers are invisible behind routers nowadays), Mirror Drivers (using DFMirage's Mirror Driver (http://www.demoforge.com/dfmirage.htm) for realtime screen grabbing on the remote computer). That being said, this program has a concept of being a client-server architecture, but I made only one program with both the functionality of client and server. That way, when the user runs my program, they can switch between giving assistance and receiving assistance without having to download a separate client or server module. I have a Windows Form that allows the user to choose between giving assistance and receiving assistance. I have another Windows Form for a file explorer module. I have another Windows Form for a chat module. I have another Windows Form form for a registry editor module. I have another Windows Form for the live control module. So I've got a Form for each module, which raises the first question: 1. Should I process module-specific commands inside the code of the respective Windows Form? Meaning, let's say I get a command with some data that enumerates the remote user's files for a specific directory. Obviously, I would have to update this on the File Explorer Windows Form and add the entries to the ListView. Should I be processing this code inside the Windows Form though? Or should I be handling this in another class (although I have to eventually pass the data to the Form to draw, of course). Or is it like a hybrid in which I process most of the data in another class and pass the final result to the Form to draw? So I've got like 5-6 forms, one for each module. The user starts up my program, enters the remote machine's ID (not IP, ID, because we are registering with an intermediary server to enable NAT traversal), their password, and connects. Now let's suppose the connection is successful. Then the user is presented with a form with all the different modules. So he can open up a File Explorer, or he can mess with the Registry Editor, or he can choose to Chat with his buddy. So now the program is sort of idle, just waiting for the user to do something. If the user opens up Live Control, then the program will be spending most of it's time receiving packets from the remote machine and drawing them to the form to provide a 'live' view. 2. Second design question. A spin off question #1. How would I pass module-specific commands to their respective Windows Forms? What I mean is, I have a class like "NetworkHandler.cs" that checks for messages from the remote machine. NetworkHandler.cs is a static class globally accessible. So let's say I get a command that enumerates the remote user's files for a specific directory. How would I "give" that command to the File Explorer Form. I was thinking of making an OnCommandReceivedEvent inside NetworkHandler, and having each form register to that event. When the NetworkHandler received a command, it would raise the event, all forms would check it to see if it was relevant, and the appropriate form would take action. Is this an appropriate/the best solution available? 3. The networking library I'm using, Lidgren, provides two options for checking networking messages. One can either poll ReadMessage() to return null or a message, or one can use an AutoResetEvent OnMessageReceived (I'm guessing this is like an event). Which one is more appropriate?

    Read the article

  • Alternatives to LINQ To SQL on high loaded pages

    - by Alex
    To begin with, I LOVE LINQ TO SQL. It's so much easier to use than direct querying. But, there's one great problem: it doesn't work well on high loaded requests. I have some actions in my ASP.NET MVC project, that are called hundreds times every minute. I used to have LINQ to SQL there, but since the amount of requests is gigantic, LINQ TO SQL almost always returned "Row not found or changed" or "X of X updates failed". And it's understandable. For instance, I have to increase some value by one with every request. var stat = DB.Stats.First(); stat.Visits++; // .... DB.SubmitChanges(); But while ASP.NET was working on those //... instructions, the stats.Visits value stored in the table got changed. I found a solution, I created a stored procedure UPDATE Stats SET Visits=Visits+1 It works well. Unfortunately now I'm getting more and more moments like that. And it sucks to create stored procedures for all cases. So my question is, how to solve this problem? Are there any alternatives that can work here? I hear that Stackoverflow works with LINQ to SQL. And it's more loaded than my site.

    Read the article

  • Using Subsonic 3.0 Advanced Templates

    - by umit
    Hi all, I've been trying to use Subsonic Advanced Templates in a project for a while but most of the time I find myself writing a Stored Procedure as I can't find a proper way of doing it in code. Subsonic created corresponding objects for my DB tables and for foreign keys it created IQueryable fields inside each object. These fields are not loaded by default and a new SQL query is executed when you access them. 1- Is there a way to get all data in one query (deep load)? Also these fields can not be assigned. So when I want to create an object in a maintenance page, I can't put all the data into this object before saving it in DB: Post post = new Post(); //get photos for this post IList<PostPhoto> postPhotos = GetPostPhotos(); post.PostPhotos = postPhotos; 2- Is it possible to have one Post object with all fields set from user input? Think of the Post object above and assume I've successfully assigned its fields. Now I need to save it to the DB. 3- Is using BatchQuery the only way to do it in one query? If I have 4 photos in PostPhotos field; 2 of them previously saved and 2 of them new, can I use the Update method to handle both the adding and updating of these photos? Any ideas or links are appreciated. Cheers...

    Read the article

  • PHP Cookie Warning...

    - by Nano HE
    Hi,I am new to PHP, I practised PHP setcookie() just now and failed. http://localhost/test/index.php <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title></title> </head> <body> <?php $value = 'something from somewhere'; setcookie("TestCookie", $value); ?> </body> </html> http://localhost/test/view.php <?php // I plan to view the cookie value via view.php echo $_COOKIE["TestCookie"]; ?> But I failed to run index.php, IE warning like this. Warning: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\test\index.php:9) in C:\xampp\htdocs\test\index.php on line 12 I enabled my IE 6 cookie no doubt. Is there anything wrong on my procedure above? Thank you. WinXP OS and XAMPP 1.7.3 used.

    Read the article

  • Problem uploading app to google app engine

    - by Oberon
    I'm having problems uploading an app to the google-app-engine from my work place. I believe the problem is related to proxy, because I do not see the same problem when following the same procedure from home. (I do not specify HTTP_PROXY from home). These are the commands I run: HTTP_PROXY=http://proxy.<thehostname>.com:8080 HTTP_PROXY=https://proxy.<thehostname>.com:8080 appcfg.py --insecure update myappfolder When running the commands I get prompted for email and password, as expected, but after that it immediately exits with this errormessage: Error 302: --- begin server output --- <HTML> <HEAD> <TITLE>Moved Temporarily</TITLE> </HEAD> <BODY BGCOLOR="#FFFFFF" TEXT="#000000"> <H1>Moved Temporarily</H1> The document has moved <A HREF="https://www.google.com/accounts/ClientLogin">here</A>. </BODY> </HTML> --- end server output --- Note: I added the --insecure option because else it gave a warning of missing ssl module. Any idea how to solve or workaround this problem?

    Read the article

  • How to add second JOIN clause in Linq To Sql?

    - by Refracted Paladin
    I am having a lot of trouble coming up with the Linq equivalent of this legacy stored procedure. The biggest hurdle is it doesn't seem to want to let me add a second 'clause' on the join with tblAddress. I am getting a Cannot resolve method... error. Can anyone point out what I am doing wrong? Below is, first, the SPROC I need to convert and, second, my LINQ attempt so far; which is FULL OF FAIL! Thanks SELECT dbo.tblPersonInsuranceCoverage.PersonInsuranceCoverageID, dbo.tblPersonInsuranceCoverage.EffectiveDate, dbo.tblPersonInsuranceCoverage.ExpirationDate, dbo.tblPersonInsuranceCoverage.Priority, dbo.tblAdminInsuranceCompanyType.TypeName AS CoverageCategory, dbo.tblBusiness.BusinessName, dbo.tblAdminInsuranceType.TypeName AS TypeName, CASE WHEN dbo.tblAddress.AddressLine1 IS NULL THEN '' ELSE dbo.tblAddress.AddressLine1 END + ' ' + CASE WHEN dbo.tblAddress.CityName IS NULL THEN '' ELSE '<BR>' + dbo.tblAddress.CityName END + ' ' + CASE WHEN dbo.tblAddress.StateID IS NULL THEN '' WHEN dbo.tblAddress.StateID = 'ns' THEN '' ELSE dbo.tblAddress.StateID END AS Address FROM dbo.tblPersonInsuranceCoverage LEFT OUTER JOIN dbo.tblInsuranceCompany ON dbo.tblPersonInsuranceCoverage.InsuranceCompanyID = dbo.tblInsuranceCompany.InsuranceCompanyID LEFT OUTER JOIN dbo.tblBusiness ON dbo.tblBusiness.BusinessID = dbo.tblInsuranceCompany.BusinessID LEFT OUTER JOIN dbo.tblAddress ON dbo.tblAddress.BusinessID = dbo.tblBusiness.BusinessID and tblAddress.AddressTypeID = 'b' LEFT OUTER JOIN dbo.tblAdminInsuranceCompanyType ON dbo.tblPersonInsuranceCoverage.InsuranceCompanyTypeID = dbo.tblAdminInsuranceCompanyType.InsuranceCompanyTypeID LEFT OUTER JOIN dbo.tblAdminInsuranceType ON dbo.tblPersonInsuranceCoverage.InsuranceTypeID = dbo.tblAdminInsuranceType.InsuranceTypeID WHERE tblPersonInsuranceCoverage.PersonID = @PersonID var coverage = from insuranceCoverage in context.tblPersonInsuranceCoverages where insuranceCoverage.PersonID == personID join insuranceCompany in context.tblInsuranceCompanies on insuranceCoverage.InsuranceCompanyID equals insuranceCompany.InsuranceCompanyID join address in context.tblAddresses on insuranceCompany.tblBusiness.BusinessID equals address.BusinessID where address.AddressTypeID = 'b' select new { insuranceCoverage.PersonInsuranceCoverageID, insuranceCoverage.EffectiveDate, insuranceCoverage.ExpirationDate, insuranceCoverage.Priority, CoverageCategory = insuranceCompany.tblAdminInsuranceCompanyType.TypeName, insuranceCompany.tblBusiness.BusinessName, TypeName = insuranceCoverage.InsuranceTypeID, Address = };

    Read the article

  • Are there any security issues to avoid when providing a email-or-username-can-act-as-username login

    - by Tchalvak
    I am in the process of moving from a "username/password" system to one that uses email for login. I don't think that there's any horrible problem with allowing either email or username for login, and I remember seeing sites that I consider somewhat respectable doing it as well, but I'd like to be aware of any major security flaws that I may be introducing. More specifically, here is the pertinent function (the query_row function parameterizes the sql). function authenticate($p_user, $p_pass) { $user = (string)$p_user; $pass = (string)$p_pass; $returnValue = false; if ($user != '' && $pass != '') { // Allow login via username or email. $sql = "SELECT account_id, account_identity, uname, player_id FROM accounts join account_players on account_id=_account_id join players on player_id = _player_id WHERE lower(account_identity) = lower(:login) OR lower(uname) = lower(:login) AND phash = crypt(:pass, phash)"; $returnValue = query_row($sql, array(':login'=>$user, ':pass'=>$pass)); } return $returnValue; } Notably, I have added the WHERE lower(account_identity) = lower(:login) OR lower(uname) = lower(:login) ...etc section to allow graceful backwards compatibility for users who won't be used to using their email for the login procedure. I'm not completely sure that that OR is safe, though. Are there some ways that I should tighten the security of the php code above?

    Read the article

  • What is the best way to handle the Connections to MySql from c#

    - by srk
    I am working on a c# application which connects to MySql server. There are about 20 functions which will connect to database. This application will be deployed in 200 over machines. I am using the below code to connect to my database which is identical for all the functions. The problem is, i can some connections were not closed and still alive when deployed in 200 over machines. Connection String : <add key="Con_Admin" value="server=test-dbserver; database=test_admindb; uid=admin; password=1Password; Use Procedure Bodies=false;" /> Declaration of the connection string Globally in application [Global.cs] : public static MySqlConnection myConn_Instructor = new MySqlConnection(ConfigurationSettings.AppSettings["Con_Admin"]); Function to query database : public static DataSet CheckLogin_Instructor(string UserName, string Password) { DataSet dsValue = new DataSet(); //MySqlConnection myConn = new MySqlConnection(ConfigurationSettings.AppSettings["Con_Admin"]); try { string Query = "SELECT accounts.str_nric AS Nric, accounts.str_password AS `Password`," + " FROM accounts " + " WHERE accounts.str_nric = '" + UserName + "' AND accounts.str_password = '" + Password + "\'"; MySqlCommand cmd = new MySqlCommand(Query, Global.myConn_Instructor); MySqlDataAdapter da = new MySqlDataAdapter(); if (Global.myConn_Instructor.State == ConnectionState.Closed) { Global.myConn_Instructor.Open(); } cmd.ExecuteScalar(); da.SelectCommand = cmd; da.Fill(dsValue); Global.myConn_Instructor.Close(); } catch (Exception ex) { Global.myConn_Instructor.Close(); ExceptionHandler.writeToLogFile(System.Environment.NewLine + "Target : " + ex.TargetSite.ToString() + System.Environment.NewLine + "Message : " + ex.Message.ToString() + System.Environment.NewLine + "Stack : " + ex.StackTrace.ToString()); } return dsValue; }

    Read the article

  • Merge computed data from two tables back into one of them

    - by Tyler McHenry
    I have the following situation (as a reduced example). Two tables, Measures1 and Measures2, each of which store an ID, a Weight in grams, and optionally a Volume in fluid onces. (In reality, Measures1 has a good deal of other data that is irrelevant here) Contents of Measures1: +----+----------+--------+ | ID | Weight | Volume | +----+----------+--------+ | 1 | 100.0000 | NULL | | 2 | 200.0000 | NULL | | 3 | 150.0000 | NULL | | 4 | 325.0000 | NULL | +----+----------+--------+ Contents of Measures2: +----+----------+----------+ | ID | Weight | Volume | +----+----------+----------+ | 1 | 75.0000 | 10.0000 | | 2 | 400.0000 | 64.0000 | | 3 | 100.0000 | 22.0000 | | 4 | 500.0000 | 100.0000 | +----+----------+----------+ These tables describe equivalent weights and volumes of a substance. E.g. 10 fluid ounces of substance 1 weighs 75 grams. The IDs are related: ID 1 in Measures1 is the same substance as ID 1 in Measures2. What I want to do is fill in the NULL volumes in Measures1 using the information in Measures2, but keeping the weights from Measures1 (then, ultimately, I can drop the Measures2 table, as it will be redundant). For the sake of simplicity, assume that all volumes in Measures1 are NULL and all volumes in Measures2 are not. I can compute the volumes I want to fill in with the following query: SELECT Measures1.ID, Measures1.Weight, (Measures2.Volume * (Measures1.Weight / Measures2.Weight)) AS DesiredVolume FROM Measures1 JOIN Measures2 ON Measures1.ID = Measures2.ID; Producing: +----+----------+-----------------+ | ID | Weight | DesiredVolume | +----+----------+-----------------+ | 4 | 325.0000 | 65.000000000000 | | 3 | 150.0000 | 33.000000000000 | | 2 | 200.0000 | 32.000000000000 | | 1 | 100.0000 | 13.333333333333 | +----+----------+-----------------+ But I am at a loss for how to actually insert these computed values into the Measures1 table. Preferably, I would like to be able to do it with a single query, rather than writing a script or stored procedure that iterates through every ID in Measures1. But even then I am worried that this might not be possible because the MySQL documentation says that you can't use a table in an UPDATE query and a SELECT subquery at the same time, and I think any solution would need to do that. I know that one workaround might be to create a new table with the results of the above query (also selecting all of the other non-Volume fields in Measures1) and then drop both tables and replace Measures1 with the newly-created table, but I was wondering if there was any better way to do it that I am missing.

    Read the article

  • Connecting to SQL Server 2005 via Web Service

    - by clear-cycle-corp
    Delphi 2010, dbExpress, and SQL Server 2005 DB I am trying to make a connection to a SQL Server 2005 DB using Delphi 2010 & DBExpress. If I create a standard delphi application and hard code my connection (IT WORKS!): procedure TForm1.Button1Click(Sender: TObject); var Conn: TSQLConnection; begin Conn:= TSQLConnection.Create(nil); Conn.ConnectionName:= 'VPUCDS_VPN_SE01'; Conn.LoadParamsOnConnect := True; Conn.LoginPrompt:=True; try Conn.Connected:= True; if Conn.Connected then ShowMessage('Connected!') else ShowMessage('NOT Connected!') finally Conn.Free; end; end; All the ini files, and DLLs reside in the same folder as my executable and yes, I have DBXMsSQL & MidasLib in the uses clause again, it works if its not a web service! However, if i then move the code over to a Web services CGI module: function TTest.ConnectToDB: Boolean;stdcall; var Conn: TSQLConnection; begin Conn:= TSQLConnection.Create(nil); Conn.ConnectionName:= 'VPUCDS_VPN_SE01'; Conn.LoadParamsOnConnect := True; Conn.LoginPrompt:=True; try Conn.Connected:= True; result:= Conn.Connected; finally Conn.Free; end; end; Thanks

    Read the article

  • confusion about using types instead of gtts in oracle

    - by Omnipresent
    I am trying to convert queries like below to types so that I won't have to use GTT: insert into my_gtt_table_1 (house, lname, fname, MI, fullname, dob) (select house, lname, fname, MI, fullname, dob from (select 'REG' house, mbr_last_name lname, mbr_first_name fname, mbr_mi MI, mbr_first_name || mbr_mi || mbr_last_name fullname, mbr_dob dob from table_1 a, table_b where a.head = b.head and mbr_number = '01' and mbr_last_name = v_last_name) c above is just a sample but complex queries are bigger than this. the above is inside a stored procedure. So to avoid the gtt (my_gtt_table_1). I did the following: create or replace type lname_row as object ( house varchar2(30) lname varchar2(30), fname varchar2(30), MI char(1), fullname VARCHAR2(63), dob DATE ) create or replace type lname_exact as table of lname_row Now in the SP: type lname_exact is table of <what_table_should_i_put_here>%rowtype; tab_a_recs lname_exact; In the above I am not sure what table to put as my query has nested subqueries. query in the SP: (I am trying this for sample purpose to see if it works) select lname_row('', '', '', '', '', '', sysdate) bulk collect into tab_a_recs from table_1; I am getting errors like : ORA-00913: too many values I am really confused and stuck with this :(

    Read the article

  • Visual Studio 2010 randomly unable to debug WCF service.

    - by rossisdead
    I'm running Visual Studio 2010 on a Windows 7 x64 machine, and occasionally VS is giving me the good old "The remote procedure could not be debugged.This usually indicates that debugging has not been enabled on the server" error that a lot of people ask about. My problem, though, is that it seems to only do this randomly(it can be anywhere from a few minutes to a few hours), and after I've made plenty of successful calls to the service already. It doesn't prevent the service from working. It still returns values and doesn't throw any errors. The only difference is that annoying dialog pops up everytime I start to debug my application. I should mention that I'm connecting the WCF service from a WPF application. If I launch the web site the service is part of, I don't get the dialog. A few of the things I've tried that do not work: Killing and restarting the server. Compiling the web server in x86 Enabling tracing, but couldn't find any problems. Is this just a bug in Visual Studio 2010, or is there something I'm missing?

    Read the article

  • How to maintain a persistant network-connection between two applications over a network?

    - by John
    I was recently approached by my management with an interesting problem - where I am pretty sure I am telling my bosses the correct information but I really want to make sure I am telling them the correct stuff. I am being asked to develop some software that has this function: An application at one location is constantly processing real-time data every second and only generates data if the underlying data has changed in any way. On the event that the data has changed send the results to another box over a network Maintains a persistent connection between the both machines, altering the remote box if for some reason the network connection went down From what I understand, I imagine that I need to do some reading on doing some sort of TCP/IP socket-level stuff. That way if the connection is dropped the remote location will be aware that the data it has received may be stale. However management seems to be very convinced that this can be accomplished using SOAP. I was under the impression that SOAP is more or less a way for a client to initiate a procedure from a server and get some results via the HTTP protocol. Am I wrong in assuming this? I haven't been able to find much information on how SOAP might be able to solve a problem like this. I feel like a lot of people around my office are using SOAP as a buzzword and that has generated a bit of confusion over what SOAP actually is - and is capable of. Any thoughts on how to accomplish this task would be appreciated!

    Read the article

  • Looking for best practise for writing a serial device communication app in C#

    - by cdotlister
    I am pretty new to serial comms, but would like advise on how to best achieve a robust application which speak to and listens to a serial device. I have managed to make use of System.IO.serialport, and successfully connected to, sent data to and recieved from my device. The way things work is this. My application connects to the Com Port and opens the port.... I then connect my device to the com port, and it detects a connectio to the PC, so sends a bit of text. it's really just copyright info, as well as the version of the firmware. I don't do anything with that, except display it in my 'activity' window. The device then waits. I can then query information, but sending a command such as 'QUERY PARAMETER1'. It then replies with something like: 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n' I then process that. I can then update it by sending 'SET PARAMETER1 12345', and it will reply with 'QUERY PARAMETER1\r\n\r\n12345\r\n\r\n'. All pretty basic. So, what I have done is created a Communication Class. this call is called in it's own thread, and sends data back to the main form... and also allows me to send messages to it. Sending data is easy. Recieving is a bit more tricky. I have employed the use of the datarecieved event, and when ever data comes in, I echo that to my screen. My problem is this: When I send a command, I feel I am being very dodgy in my handling. What I am doing is, lets say I am sending 'QUERY PARAMETER1'. I send the command to the device, I then put 'PARAMETER1' into a global variable, and I do a Thread.Sleep(100). On the data recieved, I then have a bit of logic that checks the incoming data, and sees if the string CONTAINS the value in the gloabl variable. As the reply may be 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n', it sees that it contains my parameter, parses the string, and returns the value I am looking for, but placing it into another global variable. My sending method was sleeping for 100ms. It then wakes, and checks the returned global variable. If it has data... then I'm happy, and I process the data. Problem is... if the sleep is too short.. it will fail. And I feel it's flakey.. putting stuff into variables.. then waiting... The other option is to use ReadLine instead, but that's very blocking. So I remove the datarecieved method, and instead... just send the data... then call ReadLine(). That may give me better results. There's no time, except when we connect initially, that data comes from the device, without me requesting it. So, maybe readline will be simpler and safer? Is this known as 'Blocking' reads? Also, can I set a timeout? Hopefully someone can guide me.

    Read the article

  • XAML get new width and height for Canvas

    - by Jack Navarro
    I have searched through many times but have not seen this before. Probably really simple question but can't wrap my head around it. Wrote a VSTO add-in for Excel that draws a Grid dynamically. Then launches a new window and replaces the contents of the Canvas with the generated Grid. The problem is with printing. When I call the print procedure the canvas.height and canvas.width returned is the old value prior to replacing it with the grid. Sample: string="<Grid Name=\"CanvasGrid\" xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\">..Lots of stuff..</Grid>"; // Launch new window and replace the Canvas element WpfUserControl newWindow = new WpfUserControl(); newWindow.Show(); //To test MessageBox.Show(myCanvas.ActualWidth.ToString()); //return 894 Grid testGrid = myCanvas.FindName("CanvasGrid") as Grid; MessageBox.Show("Grid " + testGrid.ActualWidth.ToString()); //return 234 StringReader stringReader = new StringReader(LssAllcChrt); XmlReader xmlReader = XmlReader.Create(stringReader); Canvas myCanvas = newWindow.FindName("GrphCnvs") as Canvas; myCanvas.Children.Clear(); myCanvas.Children.Add((UIElement)XamlReader.Load(xmlReader)); //To test MessageBox.Show(myCanvas.ActualWidth.ToString()); //return 894 but should be much larger the Grid spans all three of my screens Grid testGrid = myCanvas.FindName("CanvasGrid") as Grid; MessageBox.Show("Grid " + testGrid.ActualWidth.ToString()); //return 234 but should be much larger the Grid spans all three of my screens //Run code from WpfUserControl.cs after it loads from button click Grid testGrid = canvas.FindName("CanvasGrid") as Grid; MessageBox.Show("Grid " + testGrid.ActualWidth.ToString()); //return 234 but should be much larger the Grid spans all three of my screens So basically I have no way of telling what my new width and height are.

    Read the article

  • NullPointerException in generated JSP code calling setJspId()

    - by Dobbo
    I am trying to deploy the Duke's Bank example form the J2EE 5 tutorial on JBoss 7.1.1. I have only used (unaltered) the source, and the standard XML configuration files for deployment, part of the exercise here is to see how I might structure a JSP based project of my own. The exception I get is as follows: ERROR [[jsp]] Servlet.service() for servlet jsp threw exception: java.lang.NullPointerException at javax.faces.webapp.UIComponentClassicTagBase.setJspId(UIComponentClassicTagBase.java:1858) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at org.apache.jsp.main_jsp._jspx_meth_f_005fview_005f0(main_jsp.java:99) at org.apache.jsp.main_jsp._jspService(main_jsp.java:76) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) [jbossweb-7.0.13.Final.jar:] at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [jboss-servlet-api_3.0_spec-1.0.0.Final.jar:1.0.0.Final] at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369) [jbossweb-7.0.13.Final.jar:] at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:326) [jbossweb-7.0.13.Final.jar:] at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:253) [jbossweb-7.0.13.Final.jar:] at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [jboss-servlet-api_3.0_spec-1.0.0.Final.jar:1.0.0.Final] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:397) [jbossweb-7.0.13.Final.jar:] at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.1.1.Final.jar:7.1.1.Final] at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:] at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:] at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:] at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:] at java.lang.Thread.run(Thread.java:636) [rt.jar:1.6.0_18] I have not given any JBoss configuration files, the WAR's WEB-INF part looks like this: $ jar tvf build/lib/dukebank-web.war 0 Sat Dec 15 22:00:12 GMT 2012 META-INF/ 123 Sat Dec 15 22:00:10 GMT 2012 META-INF/MANIFEST.MF 0 Sat Dec 15 22:00:12 GMT 2012 WEB-INF/ 2514 Fri Dec 14 14:29:20 GMT 2012 WEB-INF/web.xml 1348 Sat Dec 15 08:19:46 GMT 2012 WEB-INF/dukesBank.tld 7245 Sat Dec 15 08:19:46 GMT 2012 WEB-INF/faces-config.xml 2153 Sat Dec 15 08:19:46 GMT 2012 WEB-INF/tutorial-template.tld 0 Sat Dec 15 22:00:12 GMT 2012 WEB-INF/classes/... The JSP file (main.jsp) that causes this problem is: <f:view> <h:form> <jsp:include page="/template/template.jsp"/> <center> <h3><h:outputText value="#{bundle.Welcome}"/></h3> </center> </h:form> </f:view> The template file it includes: <%@ taglib uri="/WEB-INF/tutorial-template.tld" prefix="tt" %> <%@ page errorPage="/template/errorpage.jsp" %> <%@ include file="/template/screendefinitions.jspf" %> <html> <head> <title> <tt:insert definition="bank" parameter="title"/> </title> <link rel="stylesheet" type="text/css" href="stylesheet.css"> </head> <body bgcolor="#ffffff"> <tt:insert definition="bank" parameter="banner"/> <tt:insert definition="bank" parameter="links"/> </body> </html> I will refrain from coping any more files because, as I said at the start I haven't altered any of the files I have used. Many thanks for your help, Steve

    Read the article

  • Do database engines other than SQL Server behave this way?

    - by Yishai
    I have a stored procedure that goes something like this (pseudo code) storedprocedure param1, param2, param3, param4 begin if (param4 = 'Y') begin select * from SOME_VIEW order by somecolumn end else if (param1 is null) begin select * from SOME_VIEW where (param2 is null or param2 = SOME_VIEW.Somecolumn2) and (param3 is null or param3 = SOME_VIEW.SomeColumn3) order by somecolumn end else select somethingcompletelydifferent end All ran well for a long time. Suddenly, the query started running forever if param4 was 'Y'. Changing the code to this: storedprocedure param1, param2, param3, param4 begin if (param4 = 'Y') begin set param2 = null set param3 = null end if (param1 is null) begin select * from SOME_VIEW where (param2 is null or param2 = SOME_VIEW.Somecolumn2) and (param3 is null or param3 = SOME_VIEW.SomeColumn3) order by somecolumn end else select somethingcompletelydifferent And it runs again within expected parameters (15 seconds or so for 40,000+ records). This is with SQL Server 2005. The gist of my question is this particular "feature" specific to SQL Server, or is this a common feature among RDBMS' in general that: Queries that ran fine for two years just stop working as the data grows. The "new" execution plan destroys the ability of the database server to execute the query even though a logically equivalent alternative runs just fine? This may seem like a rant against SQL Server, and I suppose to some degree it is, but I really do want to know if others experience this kind of reality with Oracle, DB2 or any other RDBMS. Although I have some experience with others, I have only seen this kind of volume and complexity on SQL Server, so I'm curious if others with large complex databases have similar experience in other products.

    Read the article

  • Entity Framework autoincrement key

    - by Tommy Ong
    I'm facing an issue of duplicated incremental field on a concurrency scenario. I'm using EF as the ORM tool, attempting to insert an entity with a field that acts as a incremental INT field. Basically this field is called "SequenceNumber", where each new record before insert, will read the database using MAX to get the last SequenceNumber, append +1 to it, and saves the changes. Between the getting of last SequenceNumber and Saving, that's where the concurrency is happening. I'm not using ID for SequenceNumber as it is not a unique constraint, and may reset on certain conditions such as monthly, yearly, etc. InvoiceNumber | SequenceNumber | DateCreated INV00001_08_14 | 1 | 25/08/2014 INV00001_08_14 | 1 | 25/08/2014 <= (concurrency is creating two SeqNo 1) INV00002_08_14 | 2 | 25/08/2014 INV00003_08_14 | 3 | 26/08/2014 INV00004_08_14 | 4 | 27/08/2014 INV00005_08_14 | 5 | 29/08/2014 INV00001_09_14 | 1 | 01/09/2014 <= (sequence number reset) Invoice number is formatted based on the SequenceNumber. After some research I've ended up with these possible solutions, but wanna know the best practice 1) Optimistic Concurrency, locking the table from any reads until the current transaction is completed (not fancy of this idea as I guess performance will be of a great impact?) 2) Create a Stored Procedure solely for this purpose, does select and insert on a single statement as such concurrency is at minimum (would prefer a EF based approach if possible)

    Read the article

< Previous Page | 646 647 648 649 650 651 652 653 654 655 656 657  | Next Page >