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  • PHP mySQL database check

    - by kielie
    Hi guys, I am having endless troubles with duplicate entries, so I need to check the database, and if a user has already entered that day, their entry will not be submitted and they will be redirected to a landing page that tells them they have already entered that day, and that they may only enter again tomorrow. The field I would like to check is the id_number field in the database, since each user has a unique id number, so basically, if a user with the same id number submitted on the same date they should be redirected to a landing page, how would I go about doing this? I am still new to a lot of this, so please be forgiving. Thanx in advance.

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  • Database connection management in Spring

    - by ria
    Do we have to explicitly manage database resources when using Spring Framework.. liking closing all open connections etc? I have read that Spring relieves developer from such boiler plate coding... This is to answer an error that I am getting in a Spring web app: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: ORA-00020: maximum number of processes (150) exceeded The jdbcTemplate is configured in the xml file and the DAO implementation has reference to this jdbcTemplate bean which is used to query the database.

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  • Simple database design and LINQ

    - by Anders Svensson
    I have very little experience designing databases, and now I want to create a very simple database that does the same thing I have previously had in xml. Here's the xml: <services> <service type="writing"> <small>125</small> <medium>100</medium> <large>60</large> <xlarge>30</xlarge> </service> <service type="analysis"> <small>56</small> <medium>104</medium> <large>200</large> <xlarge>250</xlarge> </service> </services> Now, I wanted to create the same thing in a SQL database, and started doing this ( hope this formats ok, but you'll get the gist, four columns and two rows): > ServiceType Small Medium Large > > Writing 125 100 60 > > Analysis 56 104 200 This didn't work too well, since I then wanted to use LINQ to select, say, the Large value for Writing (60). But I couldn't use LINQ for this (as far as I know) and use a variable for the size (see parameters in the method below). I could only do that if I had a column like "Size" where Small, Medium, and Large would be the values. But that doesn't feel right either, because then I would get several rows with ServiceType = Writing (3 in this case, one for each size), and the same for Analysis. And if I were to add more servicetypes I would have to do the same. Simply repetitive... Is there any smart way to do this using relationships or something? Using the second design above (although not good), I could use the following LINQ to select a value with parameters sent to the method: protected int GetHourRateDB(string serviceType, Size size) { CalculatorLinqDataContext context = new CalculatorLinqDataContext(); var data = (from calculatorData in context.CalculatorDatas where calculatorData.Service == serviceType && calculatorData.Size == size.ToString() select calculatorData).Single(); return data.Hours; } But if there is another better design, could you please also describe how to do the same selection using LINQ with that design? Please keep in mind that I am a rookie at database design, so please be as explicit and pedagogical as possible :-) Thanks! Anders

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  • Caching web page data, Database or File

    - by Mahdi
    I am creating an RSS reader application that requests the RSS from my server. I mean, the RSS is first downloaded to my server, then application downloads it from my server. I want to create RSS cache for this. And for example, each RSS would be refreshed every 1 minute. So, If 10 users request RSS of example.com in 1 minute, my server will download it only for the first time, and in other 9 requests, RSS will be loaded from cache. My question is, Should I use a Database (MSSQL) for this purpose? or I should use files? I have no limit in Database size nor in file size... EDIT: I'm using ASP.NET for the server.

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  • Creating database desktop application with data manipulation in Netbeans using Java Persistence

    - by Lulu
    It's my first time to use Persistence in developing a Java program because I usually connect via JDBC. I read that for large amounts of data, it is best to use persistence. I tried playing with the CRUD example of Netbeans. It's not very helpful thought because it only connects to the DB and allows addition and deletion of records. I need something that will allow me to manipulate the data like if the value from column C1 of table T1 is such, it will retrieve data from table t2. In short, I need to apply conditions before knowing what to retrieve exactly. The example in CRUD example already has a specific table to retrieve and only acts like a database manager. How is it possible to retrieve a specific item first then from this, will determine the next steps to be done. I'm also using embedded JavaDB/Derby as my database (also my first time to use because I usually use remote mysql)

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  • Thoughts/Input about Database Design for a CMS

    - by dallasclark
    I'm just about to expand the functionality of our own CMS but was thinking of restructuring the database to make it simpler to add/edit data types and values. Currently, the CMS is quite flat - the CMS requires a field in the database for every type of stored value (manually created). The first option that comes to mind is simply a table which keeps the data types (ie: Address 1, Suburb, Email Address etc) and another table which holds values for each of these data types. Just like how Wordpress keeps values in the 'options' table, PHP serialize would be used to store an array of values. The second option is how Drupal works, the CMS creates tables for every data type. Unlike Wordpress, this can be a bit of an overkill but really useful for SQL queries when ordering and grouping by a particular value. What's everyone's thoughts?

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  • Representing a schedule in a database

    - by David Pfeffer
    I have the interesting problem of representing complex schedule data in a database. I need to be able to represent the entirety of what the iCalendar (ics) format can represent, but in my database. I don't care about insertion efficiency but query efficiency is critical. The operation I will be doing most often is providing either a single date/time or a date/time range, and trying to determine if the defined schedule matches any part of the date/time range. Other operations can be slower. For those unfamiliar, ics allows representation of a single event or a reoccuring event based on multiple times per day, days of the week, week of a month, month, year, or some combination of those. For example, the third Thursday in November, or the 25th of December, or every two weeks starting November 2nd and continuing until September the following year. Any suggestions?

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  • Are there any online database schema drawing tools?

    - by Pure.Krome
    Hi folks, i wish to draw up some database schemas. Eg, table 1 has zero to many rows in table 2, etc. It's purely for visual purposes (eg. no sql code, etc). Are there any online tools / website that offer this? (please don't say: Use Sql Server Database Diagrams, print screen, upload to image hosting service). thanks :) EDIT: Please take note of the keyword - ONLINE. I don't want any desktop solutions (because I already have one of these).

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  • In-memory Database in Excel

    - by user329174
    Hello, I am looking for a way to import a datatable from Access into an Excel variable and then run queries through this variable to speed up the process. I am trying to migrate from C# .NET where I read a data table from an access database into memory and then used LINQ to query this dataset. It is MUCH faster than how I have it currently coded in VBA where I must make lots of calls to the actual database, which is slow. I have seen the QueryTable mentioned, but it appears that this requires pasting the data into the excel sheet. I would like to keep everything in memory and minimize the interaction between the Excel Sheet and the VBA code as much as possible. I wish we didn't need to use Excel+VBA to do this, but we're kind of stuck with that for now. Thanks for the help!

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  • .NET Database Apps: Your Preferred Setup

    - by mdvaldosta
    I'm struggling to settle into a pattern for developing typical database driven apps in C# and Visual Studio. There are so many ways to set them up, using drag/drop datasets and adapters or writing the queries manually in ADO.NET or Linq to SQL, Linq to Entities, to bind or not to data bind etc etc. Where to store the connection string, in app.config or in a method or both etc etc. So many tutorials and all of them are different. Everytime I write something I start hating the way it looks and works, so I scrap it and start over. It's getting a bit tedious. Maybe it's alittle of the OCD in me. Would any of you professional developers out there share your method of setting up and structuring your database logic and maybe some sample code? It's really how to go about organizing the code and the method(s) of interacting with SQL that I'm trying to get into a routine with, one that works and won't get me laughed at by someone reviewing it.

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  • Rolling back database changes

    - by justin
    Hi, I work in team which uses Work flow management tool. I was presented with a challenge where the user should be able to roll back the changes made anytime during the flow to a certain point in the past. Surely the toll can handle it but the additional database calls that may have made during these activities have to be manually rolled back. the challenge is that there are multiple parallel paths and there different permutations of external database calls. So is there a frame work or a way to keep track of these DB calls and rollback them?. thank you, Justin

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  • Is SQL used by PDO database independent?

    - by Pheter
    Different databases have slight variations in their implementations of SQL. Does PDO handle this? If I write an SQL query that I use with PDO to access a MySQL database, and later tell PDO to start using a different type of database, will the query stop working? Or will PDO 'convert' the query so that it continues to work? If PDO does not do this, are there any PHP libraries that allow me to write SQL according to a particular syntax, and then the library will handle converting the SQL so that it will run on different databases?

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  • 'e-Commerce' scalable database model

    - by Ruben Trancoso
    I would like to understand database scalability so I've just heard a talk about Habits of Highly Scalable Web Applications http://techportal.ibuildings.com/2010/03/02/habits-of-highly-scalable-web-applications/ On it, the presenter mainly talk about relational database scalability. I also have read something about MapReduce and Column oriented tables, big tables, hypertable etc... trying to understand which are the most up to date methods to scale web application data. But the second group, to me, is being hard to understand where it fits. It serves as transactional, reliable data store? or not, its just for large access and processing and to handle fine graned operations we will ever need to rely on RDBMSs? Could someone give a comprehensive landscape for those new technologies and how to use it?

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  • Recommendations for an in memory database vs thread safe data structures

    - by yx
    TLDR: What are the pros/cons of using an in-memory database vs locks and concurrent data structures? I am currently working on an application that has many (possibly remote) displays that collect live data from multiple data sources and renders them on screen in real time. One of the other developers have suggested the use of an in memory database instead of doing it the standard way our other systems behaves, which is to use concurrent hashmaps, queues, arrays, and other objects to store the graphical objects and handling them safely with locks if necessary. His argument is that the DB will lessen the need to worry about concurrency since it will handle read/write locks automatically, and also the DB will offer an easier way to structure the data into as many tables as we need instead of having create hashmaps of hashmaps of lists, etc and keeping track of it all. I do not have much DB experience myself so I am asking fellow SO users what experiences they have had and what are the pros & cons of inserting the DB into the system?

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  • Saving image to database as varbinary, arraylength (part 2)

    - by Thomas Schoof
    This is a followup to my previous question, which got solved (thank you for that) but now I am stuck at another error. I'm trying to save an image in my database (called 'Afbeelding'), for that I made a table which excists of: id: int souce: varbinary(max) I then created a wcf service to save an 'Afbeelding' to the database. private static DataClassesDataContext dc = new DataClassesDataContext(); [OperationContract] public void setAfbeelding(Afbeelding a) { //Afbeelding a = new Afbeelding(); //a.id = 1; //a.source = new Binary(bytes); dc.Afbeeldings.InsertOnSubmit(a); dc.SubmitChanges(); } I then put a reference to the service in my project and when I press the button I try to save it to the datbase. private void btnUpload_Click(object sender, RoutedEventArgs e) { Afbeelding a = new Afbeelding(); OpenFileDialog openFileDialog = new OpenFileDialog(); openFileDialog.Filter = "JPEG files|*.jpg"; if (openFileDialog.ShowDialog() == true) { //string imagePath = openFileDialog.File.Name; //FileStream fileStream = new FileStream(imagePath, FileMode.Open, FileAccess.Read); //byte[] buffer = new byte[fileStream.Length]; //fileStream.Read(buffer, 0, (int)fileStream.Length); //fileStream.Close(); Stream stream = (Stream)openFileDialog.File.OpenRead(); Byte[] bytes = new Byte[stream.Length]; stream.Read(bytes, 0, (int)stream.Length); string fileName = openFileDialog.File.Name; a.id = 1; a.source = new Binary { Bytes = bytes }; } EditAfbeeldingServiceClient client = new EditAfbeeldingServiceClient(); client.setAfbeeldingCompleted +=new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(client_setAfbeeldingCompleted); client.setAfbeeldingAsync(a); } void client_setAfbeeldingCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e) { if (e.Error != null) txtEmail.Text = e.Error.ToString(); else MessageBox.Show("WIN"); } However, when I do this, I get the following error: System.ServiceModel.FaultException: The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter :a. The InnerException message was 'There was an error deserializing the object of type OndernemersAward.Web.Afbeelding. The maximum array length quota (16384) has been exceeded while reading XML data. This quota may be increased by changing the MaxArrayLength property on the XmlDictionaryReaderQuotas object used when creating the XML reader.'. Please see InnerException for more details. at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc) at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result) at System.ServiceModel.ClientBase`1.ChannelBase`1.EndInvoke(String methodName, Object[] args, IAsyncResult result) atOndernemersAward.EditAfbeeldingServiceReference.EditAfbeeldingServiceClient.EditAfbeeldingServiceClientChannel.EndsetAfbeelding(IAsyncResult result) at OndernemersAward.EditAfbeeldingServiceReference.EditAfbeeldingServiceClient.OndernemersAward.EditAfbeeldingServiceReference.EditAfbeeldingService.EndsetAfbeelding(IAsyncResult result) at OndernemersAward.EditAfbeeldingServiceReference.EditAfbeeldingServiceClient.OnEndsetAfbeelding(IAsyncResult result) at System.ServiceModel.ClientBase`1.OnAsyncCallCompleted(IAsyncResult result) I'm not sure what's causing this but I think it has something to do with the way I write the image to the database? (The array length is too big big, I don't really know how to change it) Thank you for your help, Thomas

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  • Repeating fields in similar database tables

    - by user1738833
    I have been tasked with working on a database that I have never seen before and I'm looking at the DB structure. Some of the central and most heavily queried and joined tables look like virtual duplicates of each other. Here's a massively simplified representation of the situation, with business-sensitive information changed, listing hypothetical table names and fields: TopLevelGroup: PK_TLGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubGroup: PK_SubGroupId, FK_ParentTopLevelGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubSubGroup: PK_SubSUbGroupId, FK_ParentSubGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK I haven't listed the types of the fields as I don't think it's particularly important to the situation. In addition, it's worth saying that rather than four repeated fields as in the example above, I'm looking at 86 repeated fields. For the most part, those fields genuinely do represent "facts" about the primary table entity, so it's not automatically wrong for that reason. In addition, the "groups" represented here have a property inheritance relationship. If DisplaysXOnBill is NULL in the SubSubGroup, it takes the value of DisplaysXOnBillfrom it's parent, the SubGroup, and so-on up to the TopLevelGroup. Further, the requirements will never require that the model extends beyond three levels, so there is no need for flexibility in that area. Is there a design smell from several tables which describe very similar entities having almost identical fields? If so, what might be a better design of the example above? I'm using the phrase "design smell" to indicate a possible problem. Of course, in any given situation, a particular design might well be the best solution. I'm looking for a more general answer - wondering what might be wrong with this design and what might be the better design were that the case. Possibly related, but not primary questions: Is this database schema in a reasonably normal form (e.g. to 3NF), insofar as can be told from the information I've provided. I can't see a problem with the requirements of 2NF and 3NF, except in their inheriting the requirements of 1NF. Is 1NF satisfied though? Are repeating groups allowed in different tables? Is there a best-practice method for implementing the inheritance relationship in a database as I require? The method above feels clunky to me because any query on the SubSubGroup necessarily needs to join onto the SubGroup and the TopLevelGroup tables to collect inherited facts, which can make even trivial joins requiring facts from the SubSubGroup table rather long-winded. There are, of course, political considerations to making a relatively large change like this. For the purpose of this question, I'm happy to ignore that fact in the interests of keeping the answers ring-fenced to the technical problem.

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  • Cakephp - detect if unable to connect to database and recover gracefully

    - by Phantz
    I have a few sites built with Cakephp. If any of these sites lose their connection to the database for whatever reason it does not handle it well. Basically it renders itself inside itself trying to display an error over and over until the browser crashes. The rendering itself inside itself is caused by the use of requestAction from elements. What I want to know is how can I check if the database connection exists I tried this in the app_controller before filter: if(!ConnectionManager::getDataSource('default')) { die(); //this will be a message instead } but it does not seem to work. Thanks

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  • ASP .net Dropdown list not saving the selected value to database

    - by user326010
    Hi In the following code i want to save the value selected by user from drop downlist into database. but whatever value is selected by user, first value of dropdown lsit is saved to database View <% =Html.DropDownList("lstUsertype", (SelectList)ViewData["UserTypeID"])%> Controller public ActionResult CreateUser() { UmUser _UmUser = new UmUser(); UMRepository _UMRepository = new UMRepository(); EvoLetDataContext db = new EvoLetDataContext(); ViewData["UserTypeID"] = new SelectList(_UMRepository.FillUserTypes(), "UserTypeID", "UserType",2); return View(_UmUser); } [AcceptVerbs(HttpVerbs.Post)] public ActionResult CreateUser(UmUser _umUser) { //try //{ if (ModelState.IsValid) { //try //{ UserRepository _UserRepository = new UserRepository(); _UserRepository.Add(_umUser); _UserRepository.Save(); return RedirectToAction("Details", new { id = _umUser.UserID }); /*} catch { ModelState.AddModelErrors(_umUser.GetRuleViolations()); }*/ } return View(); //} /*catch { return View(); }*/ }

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  • Access one database from multiple ORMs :: Caching issue

    - by kaptan
    I know this is not a good idea and the best would be to let the applications talk Web Services. But I have a situation where the legacy application is accessing a database with an ORM and I need to access the same database from the new .net application using Fluent nHibernate. So the question is what problems this will make and how to solve them? I guess the main issue is the caching. I need to disable the caching on one of the applications (which would be the new app). So how can I disable caching in nHibernate? Is there anything else that should be careful about?

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  • question on database query using hibernate in java with annotations

    - by molleman
    Hello, simple question regarding HQL(Hibernate query language) so i have user class , that can hold a list of Projects, how do i take this out of the database depending on a username, this is how i take out my user String username = "stephen"; YFUser user = (YFUser) session.createQuery("select u FROM YFUser u where u.username = :username").setParameter("username", name).uniqueResult(); but i want to take out the list of projects here is the projects list within the class YFUser(my user class); how would i query the database to get this list of projects @Entity @Table(name = "yf_user_table") public class YFUser implements Serializable,ILightEntity { ......... @OneToMany(cascade = CascadeType.ALL,fetch = FetchType.LAZY) @JoinTable(name = "YFUSER_JOIN_PROJECT", joinColumns = { @JoinColumn(name = "user_id") }, inverseJoinColumns = { @JoinColumn(name = "project_id") }) private List<Project> projects = new ArrayList<Project>();

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  • Instrumenting Database Access

    - by Whisk
    Jeff mentioned in one of the podcasts that one of the things he always does is put in instrumentation for database calls, so that he can tell what queries are causing slowness etc. This is something I've measured in the past using SQL Profiler, but I'm interested in what strategies other people have used to include this as part of the application. Is it simply a case of including a timer across each database call and logging the result, or is there a 'neater' way of doing it? Maybe there's a framework that does this for you already, or is there a flag I could enable in e.g. Linq-to-SQL that would provide similar functionality. I mainly use c# but would also be interested in seeing methods from different languages, and I'd be more interested in a 'code' way of doing this over a db platform method like SQL Profiler.

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