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  • Test the sequentiality of a column with a single SQL query

    - by LauriE
    Hey, I have a table that contains sets of sequential datasets, like that: ID set_ID some_column n 1 'set-1' 'aaaaaaaaaa' 1 2 'set-1' 'bbbbbbbbbb' 2 3 'set-1' 'cccccccccc' 3 4 'set-2' 'dddddddddd' 1 5 'set-2' 'eeeeeeeeee' 2 6 'set-3' 'ffffffffff' 2 7 'set-3' 'gggggggggg' 1 At the end of a transaction that makes several types of modifications to those rows, I would like to ensure that within a single set, all the values of "n" are still sequential (rollback otherwise). They do not need to be in the same order according to the PK, just sequential, like 1-2-3 or 3-1-2, but not like 1-3-4. Due to the fact that there might be thousands of rows within a single set I would prefer to do it in the db to avoid the overhead of fetching the data just for verification after making some small changes. Also there is the issue of concurrency. The way locking in InnoDB (repeatable read) works (as I understand) is that if I have an index on "n" then InnoDB also locks the "gaps" between values. If I combine set_ID and n to a single index, would that eliminate the problem of phantom rows appearing? Looks to me like a common problem. Any brilliant ideas? Thanks! Note: using MySQL + InnoDB

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  • Quick and easy flood protection?

    - by James P
    I have a site where a user submits a message using AJAX to a file called like.php. In this file the users message is submitted to a database and it then sends a link back to the user. In my Javascript code I disabled the text box the user types into when they submit the AJAX request. The only problem is, a malicious user can just constantly send POST requests to like.php and flood my database. So I would like to implement simple flood protection. I don't really want the hassle of another database table logging users IPs and such... as if they are flooding my site there will be a lot of database read/writes slowing it down. I thought about using sessions, like have a session that contains a timestamp that gets checked every time they send data to like.php, and if the current time is before the timestamp let them add data to the database, otherwise send out an error and block them. If they are allowed to enter something into the database, update their session with a new timestamp. What do you think? Would this be the best way to go about it or are there easier alternatives? Thanks for any help. :)

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  • Efficient database access when dealing with multiple abstracted repositories

    - by Nathan Ridley
    I want to know how most people are dealing with the repository pattern when it involves hitting the same database multiple times (sometimes transactionally) and trying to do so efficiently while maintaining database agnosticism and using multiple repositories together. Let's say we have repositories for three different entities; Widget, Thing and Whatsit. Each repository is abstracted via a base interface as per normal decoupling design processes. The base interfaces would then be IWidgetRepository, IThingRepository and IWhatsitRepository. Now we have our business layer or equivalent (whatever you want to call it). In this layer we have classes that access the various repositories. Often the methods in these classes need to do batch/combined operations where multiple repositories are involved. Sometimes one method may make use of another method internally, while that method can still be called independently. What about, in this scenario, when the operation needs to be transactional? Example: class Bob { private IWidgetRepository _widgetRepo; private IThingRepository _thingRepo; private IWhatsitRepository _whatsitRepo; public Bob(IWidgetRepository widgetRepo, IThingRepository thingRepo, IWhatsitRepository whatsitRepo) { _widgetRepo = widgetRepo; _thingRepo= thingRepo; _whatsitRepo= whatsitRepo; } public void DoStuff() { _widgetRepo.StoreSomeStuff(); _thingRepo.ReadSomeStuff(); _whatsitRepo.SaveSomething(); } public void DoOtherThing() { _widgetRepo.UpdateSomething(); DoStuff(); } } How do I keep my access to that database efficient and not have a constant stream of open-close-open-close on connections and inadvertent invocation of MSDTS and whatnot? If my database is something like SQLite, standard mechanisms like creating nested transactions are going to inherently fail, yet the business layer should not have to be concerning itself with such things. How do you handle such issues? Does ADO.Net provide simple mechanisms to handle this or do most people end up wrapping their own custom bits of code around ADO.Net to solve these types of problems?

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  • Why null reference exception in SetMolePublicInstance?

    - by OldGrantonian
    I get a "null reference" exception in the following line: MoleRuntime.SetMolePublicInstance(stub, receiverType, objReceiver, name, null); The program builds and compiles correctly. There are no complaints about any of the parameters to the method. Here's the specification of SetMolePublicInstance, from the object browser: SetMolePublicInstance(System.Delegate _stub, System.Type receiverType, object _receiver, string name, params System.Type[] parameterTypes) Here are the parameter values for "Locals": + stub {Method = {System.String <StaticMethodUnitTestWithDeq>b__0()}} System.Func<string> + receiverType {Name = "OrigValue" FullName = "OrigValueP.OrigValue"} System.Type {System.RuntimeType} objReceiver {OrigValueP.OrigValue} object {OrigValueP.OrigValue} name "TestString" string parameterTypes null object[] I know that TestString() takes no parameters and returns string, so as a starter to try to get things working, I specified "null" for the final parameter to SetMolePublicInstance. As already mentioned, this compiles OK. Here's the stack trace: Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object. at Microsoft.ExtendedReflection.Collections.Indexable.ConvertAllToArray[TInput,TOutput](TInput[] array, Converter`2 converter) at Microsoft.Moles.Framework.Moles.MoleRuntime.SetMole(Delegate _stub, Type receiverType, Object _receiver, String name, MoleBindingFlags flags, Type[] parameterTypes) at Microsoft.Moles.Framework.Moles.MoleRuntime.SetMolePublicInstance(Delegate _stub, Type receiverType, Object _receiver, String name, Type[] parameterTypes) at DeqP.Deq.Replace[T](Func`1 stub, Type receiverType, Object objReceiver, String name) in C:\0VisProjects\DecP_04\DecP\DeqC.cs:line 38 at DeqPTest.DecCTest.StaticMethodUnitTestWithDeq() in C:\0VisProjects\DecP_04\DecPTest\DeqCTest.cs:line 28 at Starter.Start.Main(String[] args) in C:\0VisProjects\DecP_04\Starter\Starter.cs:line 14 Press any key to continue . . . To avoid the null parameter, I changed the final "null" to "parameterTypes" as in the following line: MoleRuntime.SetMolePublicInstance(stub, receiverType, objReceiver, name, parameterTypes); I then tried each of the following (before the line): int[] parameterTypes = null; // if this is null, I don't think the type will matter int[] parameterTypes = new int[0]; object[] parameterTypes = new object[0]; // this would allow for various parameter types All three attempts produce a red squiggly line under the entire line for SetMolePublicInstance Mouseover showed the following message: The best overloaded method match for 'Microsoft.Moles.Framework.Moles.MoleRuntime.SetMolePublicInstance(System.Delegate, System.Type, object, string, params System.Type[])' has some invalid arguments. I'm assuming that the first four arguments are OK, and that the problem is with the params array.

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  • MS Exam 70-536 - How to throw and handle exception from thread?

    - by Max Gontar
    Hello! In MS Exam 70-536 .Net Foundation, Chapter 7 "Threading" in Lesson 1 Creating Threads there is a text: Be aware that because the WorkWithParameter method takes an object, Thread.Start could be called with any object instead of the string it expects. Being careful in choosing your starting method for a thread to deal with unknown types is crucial to good threading code. Instead of blindly casting the method parameter into our string, it is a better practice to test the type of the object, as shown in the following example: ' VB Dim info As String = o as String If info Is Nothing Then Throw InvalidProgramException("Parameter for thread must be a string") End If // C# string info = o as string; if (info == null) { throw InvalidProgramException("Parameter for thread must be a string"); } So, I've tried this but exception is not handled properly (no console exception entry, program is terminated), what is wrong with my code (below)? class Program { static void Main(string[] args) { Thread thread = new Thread(SomeWork); try { thread.Start(null); thread.Join(); } catch (InvalidProgramException ex) { Console.WriteLine(ex.Message); } finally { Console.ReadKey(); } } private static void SomeWork(Object o) { String value = (String)o; if (value == null) { throw new InvalidProgramException("Parameter for "+ "thread must be a string"); } } } Thanks for your time!

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  • byte + byte = int... why?

    - by Robert C. Cartaino
    Looking at this C# code... byte x = 1; byte y = 2; byte z = x + y; // ERROR: Cannot implicitly convert type 'int' to 'byte' The result of any math performed on byte (or short) types is implicitly cast back to an integer. The solution is to explicitly cast the result back to a byte, so... byte z = (byte)(x + y); // works What I am wondering is why? Is it architectural? Philosophical? We have: int + int = int long + long = long float + float = float double + double = double So why not: byte + byte = byte short + short = short ? A bit of background: I am performing a long list of calculations on "small numbers" (i.e. < 8) and storing the intermediate results in a large array. Using a byte array (instead of an int array) is faster (because of cache hits). But the extensive byte-casts spread through the code make it that much more unreadable.

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  • VS2008 Link Error Using SafeInt3.hpp in 64bit mode.

    - by photo_tom
    I have the below code that links and runs fine in 32bit mode - #include "safeint3.hpp" typedef SafeInt<SIZE_T> SAFE_SIZE_T; SAFE_SIZE_T sizeOfCache; SAFE_SIZE_T _allocateAmt; Where safeint3.hpp is current version that can be found on Codeplex SafeInt. For those who are unaware of it, safeint is a template class that makes working with different integer types and sizes "safe". To quote channel 9 video on software - "it writes the code that you should". Which is my case. I have a class that is managing a large in-memory cache of objects (6gb) and I am very concerned about making sure that I don't have overflow/underflow issues on my pointers/sizes/other integer variables. In this use, it solves many problems. My problem is coming when moving from 32bit dev mode to 64bit production mode. When I build the app in this mode, I'm getting the following linker warnings - 1>cachecontrol.obj : warning LNK4006: "bool __cdecl IntrinsicMultiplyUint64(unsigned __int64 const &,unsigned __int64 const &,unsigned __int64 *)" (?IntrinsicMultiplyUint64@@YA_NAEB_K0PEA_K@Z) already defined in ImageInRamCache.obj; second definition ignored 1>cachecontrol.obj : warning LNK4006: "bool __cdecl IntrinsicMultiplyInt64(__int64 const &,__int64 const &,__int64 *)" (?IntrinsicMultiplyInt64@@YA_NAEB_J0PEA_J@Z) already defined in ImageInRamCache.obj; second definition ignored While I understand I can ignore the error, I would like either (a) prevent the warning from occurring or (b) make it disappear so that my QA department doesn't flag it as a problem. And after spending some time researching it, I cannot find a way to do either.

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  • How to specify generic method type parameters partly

    - by DNNX
    I have an extension method like below: public static T GetValueAs<T, R>(this IDictionary<string, R> dictionary, string fieldName) where T : R { R value; if (!dictionary.TryGetValue(fieldName, out value)) return default(T); return (T)value; } Currently, I can use it in the following way: var dictionary = new Dictionary<string, object(); //... var list = dictionary.GetValueAs<List<int, object("A"); // this may throw ClassCastException - this is expected behavior; It works pretty fine, but the second type parameter is really annoying. Is it possible in C# 4.0 rewrite GetValueAs is such a way that the method will still be applicable to different types of string-keyed dictionaries AND there will be no need to specify second type parameter in the calling code, i.e. use var list = dictionary.GetValueAs<List<int("A"); or at least something like var list = dictionary.GetValueAs<List<int, ?("A"); instead of var list = dictionary.GetValueAs<List<int, object("A");

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  • Computation overhead in C# - Using getters/setters vs. modifying arrays directly and casting speeds

    - by Jeffrey Kern
    I was going to write a long-winded post, but I'll boil it down here: I'm trying to emulate the graphical old-school style of the NES via XNA. However, my FPS is SLOW, trying to modify 65K pixels per frame. If I just loop through all 65K pixels and set them to some arbitrary color, I get 64FPS. The code I made to look-up what colors should be placed where, I get 1FPS. I think it is because of my object-orented code. Right now, I have things divided into about six classes, with getters/setters. I'm guessing that I'm at least calling 360K getters per frame, which I think is a lot of overhead. Each class contains either/and-or 1D or 2D arrays containing custom enumerations, int, Color, or Vector2D, bytes. What if I combined all of the classes into just one, and accessed the contents of each array directly? The code would look a mess, and ditch the concepts of object-oriented coding, but the speed might be much faster. I'm also not concerned about access violations, as any attempts to get/set the data in the arrays will done in blocks. E.g., all writing to arrays will take place before any data is accessed from them. As for casting, I stated that I'm using custom enumerations, int, Color, and Vector2D, bytes. Which data types are fastest to use and access in the .net Framework, XNA, XBox, C#? I think that constant casting might be a cause of slowdown here. Also, instead of using math to figure out which indexes data should be placed in, I've used precomputed lookup tables so I don't have to use constant multiplication, addition, subtraction, division per frame. :)

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  • Reserve space for initially hidden widget in QVBoxLayout

    - by Skinniest Man
    I am using a QVBoxLayout to arrange a vertical stack of widgets. I want some of them to be initially hidden and only show up when a check box is checked. Here is an example of the code I'm using. MyWidget::MyWidget(QWidget *parent) : QWidget(parent) { QVBoxLayout *layout = new QVBoxLayout(this); QLabel *labelLogTypes = new QLabel(tr("Log Types")); m_checkBoxCsv = new QCheckBox(tr("&Delimited File (CSV)")); m_labelDelimiter = new QLabel(tr("Delimiter:")); m_lineEditDelimiter = new QLineEdit(","); checkBoxCsv_Toggled(m_checkBoxCsv-isChecked()); connect(m_checkBoxCsv, SIGNAL(toggled(bool)), SLOT(checkBoxCsv_Toggled(bool))); QHBoxLayout *layoutDelimitedChar = new QHBoxLayout(); layoutDelimitedChar-addWidget(m_labelDelimiter); layoutDelimitedChar-addWidget(m_lineEditDelimiter); m_checkBoxXml = new QCheckBox(tr("&XML File")); m_checkBoxText = new QCheckBox(tr("Plain &Text File")); // Now that everything is constructed, put it all together // in the main layout. layout-addWidget(labelLogTypes); layout-addWidget(m_checkBoxCsv); layout-addLayout(layoutDelimitedChar); layout-addWidget(m_checkBoxXml); layout-addWidget(m_checkBoxText); layout-addStretch(); } MyWidget::checkBoxCsv_Toggled(bool checked) { m_labelDelimiter-setVisible(checked); m_lineEditDelimiter-setVisible(checked); } I want m_labelDelimiter and m_lineEditDelimiter both to be initially invisible and I want their visibility to toggle with the state of m_checkBoxCsv. This code acheives the functionality I desire, but it doesn't seem to reserve space for the two initially hidden widgets. When I check the checkbox, they become visible, but everything is kind of scrunched to accomodate them. If I leave them initially visible, everything is laid out just the way I would like it. Is there any way to make the QVBoxLayout reserve space for these widgets even if they're initially invisible?

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  • WCF: collection proxy type on client

    - by Unholy
    I have the following type in wsdl (it is generated by third party tool): <xsd:complexType name="IntArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:int" /> </xsd:sequence> </xsd:complexType> Sometimes Visual Studio generates: public class IntArray : System.Collections.Generic.List<int> {} And sometimes it doesn't generate any proxy type for this wsdl and just uses int[]. Collection type in Web Service configuration is System.Array. What could be the reason for such upredictable behavior? Edited: I found the way how I can reproduce this behavior. For examle we have two types: <xsd:complexType name="IntArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:int" /> </xsd:sequence> </xsd:complexType> <xsd:complexType name="StringArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:string" /> </xsd:sequence> </xsd:complexType> VS generates: public class IntArray : System.Collections.Generic.List<int> {} public class StringArray : System.Collections.Generic.List<string> {} Now I change StringArray type: <xsd:complexType name="StringArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:string" /> <xsd:any minOccurs="0" maxOccurs="unbounded" namespace="##any" processContents="lax" /> </xsd:sequence> <xsd:anyAttribute namespace="##any" processContents="lax"/> </xsd:complexType> VS generates proxy type for StringArray only. But not for IntArray.

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  • Creating serializeable unique compile-time identifiers for arbitrary UDT's.

    - by Endiannes
    I would like a generic way to create unique compile-time identifiers for any C++ user defined types. for example: unique_id<my_type>::value == 0 // true unique_id<other_type>::value == 1 // true I've managed to implement something like this using preprocessor meta programming, the problem is, serialization is not consistent. For instance if the class template unique_id is instantiated with other_type first, then any serialization in previous revisions of my program will be invalidated. I've searched for solutions to this problem, and found several ways to implement this with non-consistent serialization if the unique values are compile-time constants. If RTTI or similar methods, like boost::sp_typeinfo are used, then the unique values are obviously not compile-time constants and extra overhead is present. An ad-hoc solution to this problem would be, instantiating all of the unique_id's in a separate header in the correct order, but this causes additional maintenance and boilerplate code, which is not different than using an enum unique_id{my_type, other_type};. A good solution to this problem would be using user-defined literals, unfortunately, as far as I know, no compiler supports them at this moment. The syntax would be 'my_type'_id; 'other_type'_id; with udl's. I'm hoping somebody knows a trick that allows implementing serialize-able unique identifiers in C++ with the current standard (C++03/C++0x), I would be happy if it works with the latest stable MSVC and GNU-G++ compilers, although I expect if there is a solution, it's not portable.

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  • How to make a plot from summaryRprof?

    - by ThorDivDev
    This is a question for an university assignment. I was given three algorithms to calculate the GCD that I already did. My problem is getting the Rprof results to a plot so I can compare them side by side. From what little understanding I have about Rprof, summaryRprof and plot is that Rprof is used like this: Rprof() #To start #functions here Rprof(NULL) #TO end summaryRprof() # to print results I understand that plot has many different types of inputs, x and y values and something called a data frame which I assume is a fancy word for table. and to draw different lines and things I need to use this: http://www.harding.edu/fmccown/r/ what I cant figure out is how to get the summaryRprof results to the plot() function. > Rprof(filename="RProfOut2.out", interval=0.0001) > gcdBruteForce(10000, 33) [1] 1 > gcdEuclid(10000, 33) [1] 1 > gcdPrimeFact(10000, 33) [1] 1 > Rprof(NULL) > summaryRprof() ?????plot???? I have been reading on stack overflow that and other sites that I can also try to use profr and proftools although I am not very clear on the usage. The only graph I have been able to make is one using plot(system.time(gcdFunction(10,100))) As always any help is appreciated.

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  • How to read from multiple queues in real-world?

    - by Leon Cullens
    Here's a theoretical question: When I'm building an application using message queueing, I'm going to need multiple queues support different data types for different purposes. Let's assume I have 20 queues (e.g. one to create new users, one to process new orders, one to edit user settings, etc.). I'm going to deploy this to Windows Azure using the 'minimum' of 1 web role and 1 worker role. How does one read from all those 20 queues in a proper way? This is what I had in mind, but I have little or no real-world practical experience with this: Create a class that spawns 20 threads in the worker role 'main' class. Let each of these threads execute a method to poll a different queue, and let all those threads sleep between each poll (of course with a back-off mechanism that increases the sleep time). This leads to have 20 threads (or 21?), and 20 queues that are being actively polled, resulting in a lot of wasted messages (each time you poll an empty queue it's being billed as a message). How do you solve this problem?

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  • Reflection and Operator Overloads in C#

    - by TenshiNoK
    Here's the deal. I've got a program that will load a given assembly, parse through all Types and their Members and compile a TreeView (very similar to old MSDN site) and then build HTML pages for each node in the TreeView. It basically takes a given assembly and allows the user to create their own MSDN-like library for it for documentation purposes. Here's the problem I've run into: whenever an operator overload is encounted in a defined class, reflection returns that as a "MethodInfo" with the name set to something like "op_Assign" or "op_Equality". I want to be able to capture these and list them properly, but I can't find anything in the MethodInfo object that is returned to accurately identify that I'm looking at an operator. I definitely don't want to just capture everything that starts with "op_", since that will most certainly (at some point) will pick up a method it's not supposed to. I know that other methods and properties that are "special cases" like this one have the "IsSpecialName" property set, but appearantly that's not the case with operators. I've been scouring the 'net and wracking my brain to two days trying to figure this one out, so any help will be greatly appreciated.

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  • Map inheritance from generic class in Linq To SQL

    - by Ksenia Mukhortova
    Hi everyone, I'm trying to map my inheritance hierarchy to DB using Linq to SQL: Inheritance is like this, classes are POCO, without any LINQ to SQL attributes: public interface IStage { ... } public abstract class SimpleStage<T> : IStage where T : Process { ... } public class ConcreteStage : SimpleStage<ConcreteProcess> { ... } Here is the mapping: <Database Name="NNN" xmlns="http://schemas.microsoft.com/linqtosql/mapping/2007"> <Table Name="dbo.Stage" Member="Stage"> <Type Name="BusinessLogic.Domain.IStage"> <Column Name="ID" Member="ID" DbType="Int NOT NULL IDENTITY" IsPrimaryKey="true" IsDbGenerated="true" AutoSync="OnInsert" /> <Column Name="StageType" Member="StageType" IsDiscriminator="true" /> <Type Name="BusinessLogic.Domain.SimpleStage" IsInheritanceDefault="true"> <Type Name="BusinessLogic.Domain.ConcreteStage" IsInheritanceDefault="true" InheritanceCode="1"/> </Type> </Type> </Table> </Database> In the runtime I get error: System.InvalidOperationException was unhandled Message="Mapping Problem: Cannot find runtime type for type mapping 'BusinessLogic.Domain.SimpleStage'." Neither specifying SimpleStage, nor SimpleStage<T> in mapping file helps - runtime keeps producing different types of errors. DC is created like this: StreamReader sr = new StreamReader(@"MappingFile.map"); XmlMappingSource mapping = XmlMappingSource.FromStream(sr.BaseStream); DataContext dc = new DataContext(@"connection string", mapping); If Linq to SQL doesn't support this, could you, please, advise some other ORM, which does. Thanks in advance, Regards! Ksenia

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  • How to throw meaningful data in exceptions ?

    - by ZeroCool
    I would like to throw exceptions with meaningful explanation ! I thought of using variable arguments worked fine but lately I figured out it's impossible to extend the class in order to implement other exception types. So I figured out using an std::ostreamstring as a an internal buffer to deal with formatting ... but doesn't compile! I guess it has something to deal with copy constructors. Anyhow here is my piece of code: class Exception: public std::exception { public: Exception(const char *fmt, ...); Exception(const char *fname, const char *funcname, int line, const char *fmt, ...); //std::ostringstream &Get() { return os_ ; } ~Exception() throw(); virtual const char *what() const throw(); protected: char err_msg_[ERRBUFSIZ]; //std::ostringstream os_; }; The variable argumens constructor can't be inherited from! this is why I thought of std::ostringstream! Any advice on how to implement such approach ?

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  • Fortran pointer as an argument to interface procedure

    - by icarusthecow
    Im trying to use interfaces to call different subroutines with different types, however, it doesnt seem to work when i use the pointer attribute. for example, take this sample code MODULE ptr_types TYPE, abstract :: parent INTEGER :: q END TYPE TYPE, extends(parent) :: child INTEGER :: m END TYPE INTERFACE ptr_interface MODULE PROCEDURE do_something END INTERFACE CONTAINS SUBROUTINE do_something(atype) CLASS(parent), POINTER :: atype ! code determines that this allocation is correct from input ALLOCATE(child::atype) WRITE (*,*) atype%q END SUBROUTINE END MODULE PROGRAM testpass USE ptr_types CLASS(child), POINTER :: ctype CALL ptr_interface(ctype) END PROGRAM This gives error Error: There is no specific subroutine for the generic 'ptr_interface' at (1) however if i remove the pointer attribute in the subroutine it compiles fine. Now, normally this wouldnt be a problem, but for my use case i need to be able to treat that argument as a pointer, mainly so i can allocate it if necessary. Any suggestions? Mind you I'm new to fortran so I may have missed something edit: forgot to put the allocation in the parents subroutine, the initial input is unallocated EDIT 2 this is my second attempt, with caller side casting MODULE ptr_types TYPE, abstract :: parent INTEGER :: q END TYPE TYPE, extends(parent) :: child INTEGER :: m END TYPE TYPE, extends(parent) :: second INTEGER :: meow END TYPE CONTAINS SUBROUTINE do_something(this, type_num) CLASS(parent), POINTER :: this INTEGER type_num IF (type_num == 0) THEN ALLOCATE (child::this) ELSE IF (type_num == 1) THEN ALLOCATE (second::this) ENDIF END SUBROUTINE END MODULE PROGRAM testpass USE ptr_types CLASS(child), POINTER :: ctype SELECT TYPE(ctype) CLASS is (parent) CALL do_something(ctype, 0) END SELECT WRITE (*,*) ctype%q END PROGRAM however this still fails. in the select statement it complains that parent must extend child. Im sure this is due to restrictions when dealing with the pointer attribute, for type safety, however, im looking for a way to convert a pointer into its parent type for generic allocation. Rather than have to write separate allocation functions for every type and hope they dont collide in an interface or something. hopefully this example will illustrate a little more clearly what im trying to achieve, if you know a better way let me know

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  • Advice on setting up a central db with master tables for web apps

    - by Dragn1821
    I'm starting to write more and more web applications for work. Many of these web applications need to store the same types of data, such as location. I've been thinking that it may be better to create a central db and store these "master" tables there and have each applicaiton access them. I'm not sure how to go about this. Should I create tables in my application's db to copy the data from the master table and store in the app's table (for linking with other app tables using foreign keys)? Should I use something like a web service to read the data from the master table instead of firing up a new db connection in my app? Should I forget this idea and just store the data within my app's db? I would like to have data such as the location central so I can go to one table and add a new location and the next time someone needs to select a location from one of the apps, the new one would be there. I'm using ASP.NET MVC 1.0 to build the web apps and SQL 2005 as the db. Need some advice... Thanks!

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  • Should I have one dll or multiple for Business Logic?

    - by Brian
    In my situation, my company services many types of customers. Almost every customer requires their own Business Logic. Of course, there will be a base layer that all business logic should inherit from. However, I'm going back and forth on architecting this--either in one dll for all customers or one dll for each. My biggest point of contention deals with upgrading the software. We have about 12 data entry personnel that work with 20 companies and it's critical that they have little down time. My concern is that if I deploy everything in one dll, I could introduce a bug in company A's logic while only intending to update Company B's logic. I believe I could reduce the risk if each company's logic had their own dll, so then, I could deploy Company B's update w/o harming Company A's. -- I will be the only one supporting this. That said, this also seems like a nightmare to manage 20 different .dll's -- that's for the BLL alone. I also need to create a View layer and ViewModel layer. So, potentially, I could have 20 (companies) * 3 (layers) which would equate to 60 .dll's. Thank You.

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  • C++ Dynamic Allocation Mismatch: Is this problematic?

    - by acanaday
    I have been assigned to work on some legacy C++ code in MFC. One of the things I am finding all over the place are allocations like the following: struct Point { float x,y,z; }; ... void someFunc( void ) { int numPoints = ...; Point* pArray = (Point*)new BYTE[ numPoints * sizeof(Point) ]; ... //do some stuff with points ... delete [] pArray; } I realize that this code is atrociously wrong on so many levels (C-style cast, using new like malloc, confusing, etc). I also realize that if Point had defined a constructor it would not be called and weird things would happen at delete [] if a destructor had been defined. Question: I am in the process of fixing these occurrences wherever they appear as a matter of course. However, I have never seen anything like this before and it has got me wondering. Does this code have the potential to cause memory leaks/corruption as it stands currently (no constructor/destructor, but with pointer type mismatch) or is it safe as long as the array just contains structs/primitive types?

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  • Advice on Minimizing Stored Procedure Parameters

    - by RPM1984
    Hi Guys, I have an ASP.NET MVC Web Application that interacts with a SQL Server 2008 database via Entity Framework 4.0. On a particular page, i call a stored procedure in order to pull back some results based on selections on the UI. Now, the UI has around 20 different input selections, ranging from a textbox, dropdown list, checkboxes, etc. Each of those inputs are "grouped" into logical sections. Example: Search box : "Foo" Checkbox A1: ticked, Checkbox A2: unticked Dropdown A: option 3 selected Checkbox B1: ticked, Checkbox B2: ticked, Checkbox B3: unticked So i need to call the SPROC like this: exec SearchPage_FindResults @SearchQuery = 'Foo', @IncludeA1 = 1, @IncludeA2 = 0, @DropDownSelection = 3, @IncludeB1 = 1, @IncludeB2 = 1, @IncludeB3 = 0 The UI is not too important to this question - just wanted to give some perspective. Essentially, i'm pulling back results for a search query, filtering these results based on a bunch of (optional) selections a user can filter on. Now, My questions/queries: What's the best way to pass these parameters to the stored procedure? Are there any tricks/new ways (e.g SQL Server 2008) to do this? Special "table" parameters/arrays - can we pass through User-Defined-Types? Keep in mind im using Entity Framework 4.0 - but could always use classic ADO.NET for this if required. What about XML? What are the serialization/de-serialization costs here? Is it worth it? How about a parameter for each logical section? Comma-seperated perhaps? Just thinking out loud. This page is particulary important from a user point of view, and needs to perform really well. The stored procedure is already heavy in logic, so i want to minimize the performance implications - so keep that in mind. With that said - what is the best approach here?

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  • Trouble accessing fields of a serialized object in Java

    - by typoknig
    I have instantized a class that implements Serializable and I am trying to stream that object like this: try{ Socket socket = new Socket("localhost", 8000); ObjectOutputStream toServer = new ObjectOutputStream(socket.getOutputStream()); toServer.writeObject(myObject); } catch (IOException ex) { System.err.println(ex); } All good so far right? Then I am trying to read the fields of that object like this: //This is an inner class class HandleClient implements Runnable{ private ObjectInputStream fromClient; private Socket socket; // This socket was established earlier try { fromClient = new ObjectInputStream(socket.getInputStream()); GetField inputObjectFields = fromClient.readFields(); double myFristVariable = inputObjectFields.get("myFirstVariable", 0); int mySecondVariable = inputObjectFields.get("mySecondVariable", 0); //do stuff } catch (IOException ex) { System.err.println(ex); } catch (ClassNotFoundException ex) { System.err.println(ex); } finally { try { fromClient.close(); } catch (Exception ex) { ex.printStackTrace(); } } } But I always get the error: java.io.NotActiveException: not in call to readObject This is my first time streaming objects instead of primitive data types, what am I doing wrong? BONUS When I do get this working correctly, is the ENTIRE CLASS passed with the serialized object (i.e. will I have access to the methods of the object's class)? My reading suggests that the entire class is passed with the object, but I have been unable to use the objects methods thus far. How exactly do I call on the object's methods? In addition to my code above I also experimented with the readObject method, but I was probably using it wrong too because I couldn't get it to work. Please enlighten me.

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  • Protocol specification in XML

    - by Mathijs
    Is there a way to specify a packet-based protocol in XML, so (de)serialization can happen automatically? The context is as follows. I have a device that communicates through a serial port. It sends and receives a byte stream consisting of 'packets'. A packet is a collection of elementary data types and (sometimes) other packets. Some elements of packets are conditional; their inclusion depends on earlier elements. I have a C# application that communicates with this device. Naturally, I don't want to work on a byte-level throughout my application; I want to separate the protocol from my application code. Therefore I need to translate the byte stream to structures (classes). Currently I have implemented the protocol in C# by defining a class for each packet. These classes define the order and type of elements for each packet. Making class members conditional is difficult, so protocol information ends up in functions. I imagine XML that looks like this (note that my experience designing XML is limited): <packet> <field name="Author" type="int32" /> <field name="Nickname" type="bytes" size="4"> <condition type="range"> <field>Author</field> <min>3</min> <max>6</min> </condition> </field> </packet> .NET has something called a 'binary serializer', but I don't think that's what I'm looking for. Is there a way to separate protocol and code, even if packets 'include' other packets and have conditional elements?

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  • In need of a Smarter Environmental Package Configuration

    - by Jeremy Liberman
    I am trying to set up a package template in SSIS, following the Wrox Programmer to Programmer book, SQL Server 2008 Integration Services: Problem - Design - Solution. I'm really liking this book even though it is 2008 and we're using SQL Server 2005. I've got a working package template that uses an Indirect XML package configuration to identify what environment (local developer, dev, QA, production, etc) the package is being run in. That locates the SQL Server package configuration for the environment. That set-up is great and all except for the environment variable at the very front of it all. My team would prefer it if the package could use the same environment resource locator as all our other applications and tools use, so we don't two environment markers with essentially the same information in them. Normally we look up a registry key in HKey_Local_Machine but the Registry Package Configuration type only lets you look up the HKey_Current_User registries. My first thought was to write a new Package Configuration Type class that extends the Registry type; after all we'd had such luck writing our own custom log provider. SSIS is super extendable, right? So there doesn't seem to be a way to write your own Package Configuration Types. Is there still some way I can configure my SSIS SQL Server package configuration from a HKLM registry key connection string? If this is not possible, what other workarounds are available? My idea is to write a PowerShell script that will create/modify the Environment Variable that the package will use by fetching the connection string from the registry. This way there's still two markers, but at least then it's automatically maintained and automated. Is this kind of workaround necessary? Thank you for your time.

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