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  • What is better for a student programming in C++ to learn for writing GUI: C# vs QT?

    - by flashnik
    I'm a teacher(instructor) of CS in the university. The course is based on Cormen and Knuth and students program algorithms in C++. But sometimes it is good to show how an algorithm works or just a result of task through GUI. Also in my opinion it's very imporant to be able to write full programs. They will have courses concerning GUI but a three years, later, in fact, before graduatuion. I think that they should be able to write simple GUI applications earlier. So I want to teach them it. How do you think, what is more useful for them to learn: programming GUI with QT or writing GUI in C# and calling unmanaged C++ library? Update. For developing C++ applications students use MS Visual studio, so C# is already installed. But QT AFAIK also can be integrated into VS. I have following pros of C# (some were suggested there in answers): The need to make an additional layer. It's more work, but it forces you explicitly specify contract between GUI and processing data. The border between GUI and algorithms becomes very clear. It's more popular among employers. At least, in Russia where we live. It's rather common to write performance-critical algorithms in C++ and PInvoke them from well-looking C# application/ASP.Net website. Maybe it is not so widespread in the rest of the world but in Russia Windows is very popular, especially in companies and corporations due to some reasons, so most of b2b applications are Windows applications. Rapid development. It's much quicker to code in .Net then in C++ due to many reasons. And the con is that it's a new language with own specific for students. And the mess with invoking calls to library.

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  • What is the strangest programming language you have used?

    - by Anders Sandvig
    For me I think it has to be the scripting language of an old proprietary telephony platform I used in the early 2000s. The language itself was not so bad, but the fact that it was meant to be edited with a drag-and-drop GUI, which did not expose all the functionality I needed, was quite frustrating. I also remember having to manually implement many common functions, such as calculating the length of a string. Whenever I wanted to use "custom" or "advanced" functions, I had to edit the script files in a text editor, but as soon as I opened the files in the GUI again they were reformatted and restructured, which usually resulted in broken code. And, of course, this was an interpreted language, so I would not know it was broken until I actually ran it—oh, and did I mention that it did not run the same in the simulator as in the live environment? So, what is the strangest programming language or environment you have used, and why did you use it? Note that I'm interested in languages and environments that you have actually used for "real-world" situations, so Whitespace, Brainf***k and friends are not valid—unless you have used them for something "real", of course.

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  • Is there some way Linux editors can tell the programming language without the file extension?

    - by vfclists
    I am editing some scripts on Linux without the languages file extensions, and it seems that the editors, namely vi, nano and gedit are not applying syntax highlighting because the filenames don't use the language extensions. Is there some parameters to be passed or some setting that can enable them to recognize the language? Update: After some googling I realize that bash has that ability, at least to do some parsing or check the shebang at the top determine the language. By default Ubuntu does not install the complete vim package, so after installing it, the shell files are recognized. I don't know about nano or gedit, but vi and its graphical counterpart will do.

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  • How to insert a list of data files(described in CSV file) from client location into database using PHP programming?

    - by Golam Mustafa
    We have some DVD. Each of them contain ---A CSV file containing some information about the documents. ---The list of pdf file(Scanned document). Example of CSV file Title,Author,FileName Design Document 0455, Eric Clipton,ds0455.pdf Tesign Document 0511,Johanson E,td0511.pdf I want to write PHP code that would read the CSV file , insert each information to database table as record. Can anybody help me to provide any idea about ---- How to select individual file from the client location on the basis of file name in the CSV file using PHP script. Thanks Golam

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  • New i7 is slower than old Core 2 Duo? Why? (BIOS programming)

    - by DrChase
    I've always wondered why the companies who make BIOS' either have terrible engineering psychologists or none at all. But without wasting your time further with random speculative questions, my real question is as follows: Why does my new computer run slower than my old computer? Old Computer: Intel Core 2 Duo CPU @ 3.0 Ghz (stock) 4GB OCZ DDR2 800 RAM Wolfdale E8400 mb nVidia GeForce 8600 GT New Computer: Intel Core i7 920 @ ~3.2 Ghz 6 GB OCZ DDR3 1066 RAM EVGA x58 SLI LE motherboard nVidia GeForce GTX 275 Vista x64 Home Premium on both. "Run slower" is defined as: - poorer FPS performance in the same games, applications - takes longer to start up - general desktop usage (checking email, opening up files, running exe's) is noticeably slower At first I thought I must've not set something up in the BIOS or something. But I have no idea how to set anything in the bios except for "Dummy O.C.", which brought me to ~3.2 Ghz. But beyond that I have no idea. I've been reading stuff about "ram timing" and voltages and the like but I really have no idea about that stuff. I'm a psychologist who has a basic understanding in building his own computers, not a computer scientist. Can someone give me some wisdom that might guide me to the reason my new computer is worse than my older one? I'm sorry if this is a bad question, or not appropriate to SO. I'm just pretty frustrated now and you all have helped me in the past so I figured I'd give it a shot. Thanks for your time.

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  • Where to place web.xml outside WAR file for secure redirect?

    - by Silverhalide
    I am running Tomcat 7 and am deploying a bunch of applications delivered to me by a third party as WAR files. I'd like to force some of those apps to always use SSL. (All the "SSL" apps are in one service; other apps outside this discussion are in another service.) I've figured out how to use conf\web.xml to redirect apps from HTTP to HTTPS, but that applies to all applications hosted by Tomcat. I've also figured out how to put web.xml in an unpacked app's web-inf directory; that does the trick for that specific app, but runs the risk of being overwritten if our vendor gives us a new war file to deploy. I've also tried placing the web.xml file in various places under conf\service\host, or under appbase, but none seem to work. Is it possible to redirect some apps to SSL without forcing all apps to redirect, or to put the web.xml file inside the extracted WAR file? Here's my server.xml: <Service name="secure"> <Connector port="80" connectionTimeout="20000" redirectPort="443" URIEncoding="UTF-8" enableLookups="false" compression="on" protocol="org.apache.coyote.http11.Http11Protocol" compressableMimeType="text/html,text/xml,text/plain,text/javascript,application/json,text/css"/> <Connector port="443" URIEncoding="UTF-8" enableLookups="false" compression="on" protocol="org.apache.coyote.http11.Http11Protocol" compressableMimeType="text/html,text/xml,text/plain,text/javascript,application/json,text/css" scheme="https" secure="true" SSLEnabled="true" sslProtocol="TLS" keystoreFile="..." keystorePass="..." keystoreType="PKCS12" truststoreFile="..." truststorePass="..." truststoreType="JKS" clientAuth="false" ciphers="SSL_RSA_WITH_RC4_128_MD5,SSL_RSA_WITH_RC4_128_SHA,TLS_RSA_WITH_AES_128_CBC_SHA,TLS_DHE_RSA_WITH_AES_128_CBC_SHA,TLS_DHE_DSS_WITH_AES_128_CBC_SHA,SSL_RSA_WITH_AES_128_CBC_SHA"/> <Engine name="secure" defaultHost="localhost"> <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/> <Host name="localhost" appBase="webapps" unpackWARs="false" autoDeploy="true" xmlValidation="false" xmlNamespaceAware="false"> </Host> </Engine> </Service> <Service name="mutual-secure"> ... </Service> The content of the web.xml files I'm playing with is: <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0" metadata-complete="true"> <security-constraint> <web-resource-collection> <web-resource-name>All applications</web-resource-name> <url-pattern>/*</url-pattern> </web-resource-collection> <user-data-constraint> <description>Redirect all requests to HTTPS</description> <transport-guarantee>CONFIDENTIAL</transport-guarantee> </user-data-constraint> </security-constraint> </web-app> (For conf\web.xml the security-constraint is added just before the end of the existing file, rather than create a new file.) My webapps directory (currently) contains only the WAR files.

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  • C socket programming: calling recv() changes my socket file descriptor?

    - by fourier
    Hey all, I have this strange problem with recv(). I'm programming client/server where client send() a message (a structure to be exact) and server recv() it. I am also working with multiple sockets and select(). while(1) { readset = info->read_set; info->copy_set = info->read_set; timeout.tv_sec = 1; timeout.tv_usec = 0; // 0.5 seconds ready = select(info->max_fd+1, &readset, NULL, NULL, &timeout); if (ready == -1) { printf("S: ERROR: select(): %s\nEXITING...", strerror(errno)); exit(1); } else if (ready == 0) { continue; } else { printf("S: oh finally you have contacted me!\n"); for(i = 0; i < (info->max_fd+1); i++) { if(FD_ISSET(i, &readset)) //this is where problem begins { printf("S: %i is set\n", i); printf("S: we talking about socket %i son\n", i); // i = 4 num_bytes = recv(i, &msg, MAX_MSG_BYTE, 0); printf("S: number of bytes recieved in socket %i is %i\n", i, num_bytes); // prints out i = 0 what?? if (num_bytes == 0) { printf("S: socket has been closed\n"); break; } else if (num_bytes == -1) { printf("S: ERROR recv: %d %s \n", i, strerror(errno)); continue; } else { handle_request(arg, &msg); printf("S: msg says %s\n", msg->_payload); } } // if (FD_ISSET(i, &readset) else printf("S: %i is not set\n", i); } // for (i = 0; i < maxfd+1; i++) to check sockets for msg } // if (ready == -1) info->read_set = info->copy_set; printf("S: copied\n"); } the problem I have is that in read_set, 0~3 aren't set and 4 is. That is fine. But when i call recv(), i suddently becomes 0. Why is that? It doesn't make sense to me why recv() would take an socket file descriptor number and modify to another number. Is that normal? Am I missing something? S: 0 is not set S: 1 is not set S: 2 is not set S: 3 is not set S: 4 is set S: we talking about socket 4 son S: i is strangely or unstrangely 0 S: number of bytes recieved in socket 0 is 40 That's what it prints out.

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  • Android addTextChangedListener onTextChanged not fired when Backspace is pressed?

    - by tsil
    I use addTextChangeListener to filter a list items. When the user enters a character on the editText, items are filtered based on user input. For example, if the user enters "stackoverflow", all items that contains "stackoverflow" are displayed. It works fine except that once the user press backspace to delete character(s), items are no longer filtered until he deletes all characters. For example, my items are: "stackoverflow 1", "stackoverflow 2", "stackoverflow 3", "stackoverflow 4". If user input is "stackoverflow", all items are displayed. If user input is "stackoverflow 1", only "stackoverflow 1" is displayed. Then user deletes the last 2 characters (1 and the space). User input is now "stackoverflow" but "stackoverflow 1" is still displayed and the other items are not displayed. This is my custom filter: private class ServiceFilter extends Filter { @Override protected FilterResults performFiltering(CharSequence constraint) { FilterResults results = new FilterResults(); if (constraint == null || constraint.length() == 0) { // No filter implemented we return all the list results.values = origServiceList; results.count = origServiceList.size(); } else { List<ServiceModel> nServiceList = new ArrayList<ServiceModel>(); for (ServiceModel s : serviceList) { if (s.getName().toLowerCase().contains(constraint.toString().toLowerCase())) { nServiceList.add(s); } } results.values = nServiceList; results.count = nServiceList.size(); } return results; } @Override protected void publishResults(CharSequence constraint, FilterResults results) { if (results.count == 0) { notifyDataSetInvalidated(); } else { serviceList = (List<ServiceModel>) results.values; notifyDataSetChanged(); } } } And how I handle text change event: inputSearch.addTextChangedListener(new TextWatcher() { @Override public void afterTextChanged(Editable arg0) { // TODO Auto-generated method stub } @Override public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) { // TODO Auto-generated method stub } @Override public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) { if (cs.length() >= 1) { mAdapter.getFilter().filter(cs); } else { mAdapter = new ServiceAdapter(MyActivity.this, R.layout.ussd_list_item, serviceList); listView.setAdapter(mAdapter); } } });

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  • Cascading Deletes in SQL Sever 2008 not working.

    - by Vaccano
    I have the following table setup. Bag | +-> BagID (Guid) +-> BagNumber (Int) BagCommentRelation | +-> BagID (Int) +-> CommentID (Guid) BagComment | +-> CommentID (Guid) +-> Text (varchar(200)) BagCommentRelation has Foreign Keys to Bag and BagComment. So, I turned on cascading deletes for both those Foreign Keys, but when I delete a bag, it does not delete the Comment row. Do need to break out a trigger for this? Or am I missing something? (I am using SQL Server 2008) Note: Posting requested SQL. This is the defintion of the BagCommentRelation table. (I had the type of the bagID wrong (I thought it was a guid but it is an int).) CREATE TABLE [dbo].[Bag_CommentRelation]( [Id] [int] IDENTITY(1,1) NOT NULL, [BagId] [int] NOT NULL, [Sequence] [int] NOT NULL, [CommentId] [int] NOT NULL, CONSTRAINT [PK_Bag_CommentRelation] PRIMARY KEY CLUSTERED ( [BagId] ASC, [Sequence] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[Bag_CommentRelation] WITH CHECK ADD CONSTRAINT [FK_Bag_CommentRelation_Bag] FOREIGN KEY([BagId]) REFERENCES [dbo].[Bag] ([Id]) ON DELETE CASCADE GO ALTER TABLE [dbo].[Bag_CommentRelation] CHECK CONSTRAINT [FK_Bag_CommentRelation_Bag] GO ALTER TABLE [dbo].[Bag_CommentRelation] WITH CHECK ADD CONSTRAINT [FK_Bag_CommentRelation_Comment] FOREIGN KEY([CommentId]) REFERENCES [dbo].[Comment] ([CommentId]) ON DELETE CASCADE GO ALTER TABLE [dbo].[Bag_CommentRelation] CHECK CONSTRAINT [FK_Bag_CommentRelation_Comment] GO The row in this table deletes but the row in the comment table does not.

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  • Two n x m relationships with the same table in mysql

    - by Christian
    I want to create a database in which there's an n x m relationship between the table drug and the table article and an n x m relationship between the table target and the table article. I get the error: Cannot delete or update a parent row: a foreign key constraint fails What do I have to change in my code? DROP TABLE IF EXISTS `textmine`.`article`; CREATE TABLE `textmine`.`article` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT 'Pubmed ID', `abstract` blob NOT NULL, `authors` blob NOT NULL, `journal` varchar(256) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS `textmine`.`drugs`; CREATE TABLE `textmine`.`drugs` ( `id` int(10) unsigned NOT NULL COMMENT 'This ID is taken from the biosemantics dictionary', `primaryName` varchar(256) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS `textmine`.`targets`; CREATE TABLE `textmine`.`targets` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `primaryName` varchar(256) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS `textmine`.`containstarget`; CREATE TABLE `textmine`.`containstarget` ( `targetid` int(10) unsigned NOT NULL, `articleid` int(10) unsigned NOT NULL, KEY `target` (`targetid`), KEY `article` (`articleid`), CONSTRAINT `article` FOREIGN KEY (`articleid`) REFERENCES `article` (`id`), CONSTRAINT `target` FOREIGN KEY (`targetid`) REFERENCES `targets` (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS `textmine`.`contiansdrug`; CREATE TABLE `textmine`.`contiansdrug` ( `drugid` int(10) unsigned NOT NULL, `articleid` int(10) unsigned NOT NULL, KEY `drug` (`drugid`), KEY `article` (`articleid`), CONSTRAINT `article` FOREIGN KEY (`articleid`) REFERENCES `article` (`id`), CONSTRAINT `drug` FOREIGN KEY (`drugid`) REFERENCES `drugs` (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

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  • getting all contacts (including from other syncAdapters) in android content handler.

    - by eyal
    Hi i have this Query: private Cursor getContacts(CharSequence constraint) { boolean hasConstrains = constraint != null && constraint.length() != 0; Uri uri = ContactsContract.Contacts.CONTENT_URI; String[] projection = new String[]{ContactsContract.Contacts._ID, ContactsContract.Contacts.DISPLAY_NAME }; String selection = hasConstrains ? projection[1] + " LIKE '"+constraint+"%'" : null; String[] selectionArgs = null; String sortOrder = ContactsContract.Contacts.DISPLAY_NAME + " ASC"; return managedQuery(uri, projection, selection, selectionArgs, sortOrder); } The first time issue it i give null as parameter to the function to the selection parameter is empty, meaning i don't filter any rows. The problem is i get only contacts i created myself using no syncAdapter. I used facebook app to synch my facebook contacts, but this query doesn't return them. I extracted the contacts2.db from the emulator and the view_contacts view shows me all the contacts, so the DB is updated. What should i do to get all the contacts regardless of how they were created (with which synch adapter)

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  • JSF SSL Hazzard

    - by java beginner
    In my application it is required that only certain pages need to be secured using SSL so I configured it security-constraint> <display-name>Security Settings</display-name> <web-resource-collection> <web-resource-name>SSL Pages</web-resource-name> <description/> <url-pattern>/*.jsp</url-pattern> <http-method>GET</http-method> <http-method>POST</http-method> </web-resource-collection> <user-data-constraint> <description>CONFIDENTIAL requires SSL</description> <transport-guarantee>CONFIDENTIAL</transport-guarantee> </user-data-constraint> and added filter http://blogs.sun.com/jluehe/entry/how_to_downshift_from_https but only one hazard is there. I am using it with richFaces. Once it goes to HTTPS its not changing the page—I mean if I perform post action it doesn't actually happen. But if I do it from the local machine's browser it works perfectly, from a remote browser it stucks with HTTPS and not changing after that. Here is my web.xml's snap: <filter> <filter-name>MyFilter</filter-name> <filter-class>MyFilter</filter-class> <init-param> <param-name>httpPort</param-name> <param-value>8080</param-value> </init-param> </filter> <filter-mapping> <filter-name>MyFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <security-constraint> <web-resource-collection> <web-resource-name>Protected resource</web-resource-name> <url-pattern>somePattern</url-pattern> <http-method>GET</http-method> <http-method>POST</http-method> </web-resource-collection> <user-data-constraint> <transport-guarantee>CONFIDENTIAL</transport-guarantee> </user-data-constraint> </security-constraint> and some other filters of richfaces. Problem is strange. If I try to access the web app from local's machine's browser it works fine but in remote machine's browser once it get into HTTP, all the forms of that page aswell as href stops working.(JSF,facelet is used.)

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  • Programming graphics and sound on PC - Total newbie questions, and lots of them!

    - by Russel
    Hello, This isn't exactly specifically a programming question (or is it?) but I was wondering: How are graphics and sound processed from code and output by the PC? My guess for graphics: There is some reserved memory space somewhere that holds exactly enough room for a frame of graphics output for your monitor. IE: 800 x 600, 24 bit color mode == 800x600x3 = ~1.4MB memory space Between each refresh, the program writes video data to this space. This action is completed before the monitor refresh. Assume a simple 2D game: the graphics data is stored in machine code as many bytes representing color values. Depending on what the program(s) being run instruct the PC, the processor reads the appropriate data and writes it to the memory space. When it is time for the monitor to refresh, it reads from each memory space byte-for-byte and activates hardware depending on those values for each color element of each pixel. All of this of course happens crazy-fast, and repeats x times a second, x being the monitor's refresh rate. I've simplified my own likely-incorrect explanation by avoiding talk of double buffering, etc Here are my questions: a) How close is the above guess (the three steps)? b) How could one incorporate graphics in pure C++ code? I assume the practical thing that everyone does is use a graphics library (SDL, OpenGL, etc), but, for example, how do these libraries accomplish what they do? Would manual inclusion of graphics in pure C++ code (say, a 2D spite) involve creating a two-dimensional array of bit values (or three dimensional to include multiple RGB values per pixel)? Is this how it would be done waaay back in the day? c) Also, continuing from above, do libraries such as SDL etc that use bitmaps actual just build the bitmap/etc files into machine code of the executable and use them as though they were build in the same matter mentioned in question b above? d) In my hypothetical step 3 above, is there any registers involved? Like, could you write some byte value to some register to output a single color of one byte on the screen? Or is it purely dedicated memory space (=RAM) + hardware interaction? e) Finally, how is all of this done for sound? (I have no idea :) )

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  • Oracle Database Enforce CHECK on multiple tables

    - by GigaPr
    I am trying to enforce a CHECK Constraint in a ORACLE Database on multiple tables CREATE TABLE RollingStocks ( Id NUMBER, Name Varchar2(80) NOT NULL, RollingStockCategoryId NUMBER NOT NULL, CONSTRAINT Pk_RollingStocks Primary Key (Id), CONSTRAINT Check_RollingStocks_CategoryId CHECK ((RollingStockCategoryId IN (SELECT Id FROM FreightWagonTypes)) OR (RollingStockCategoryId IN (SELECT Id FROM LocomotiveClasses))) ); ...but i get the following error: *Cause: Subquery is not allowed here in the statement. *Action: Remove the subquery from the statement. Can you help me understanding what is the problem or how to achieve the same result?

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  • FluentNHibernate mapping of composite foreign keys

    - by Faron
    I have an existing database schema and wish to replace the custom data access code with Fluent.NHibernate. The database schema cannot be changed since it already exists in a shipping product. And it is preferable if the domain objects did not change or only changed minimally. I am having trouble mapping one unusual schema construct illustrated with the following table structure: CREATE TABLE [Container] ( [ContainerId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Container] PRIMARY KEY ( [ContainerId] ASC ) ) CREATE TABLE [Item] ( [ItemId] [uniqueidentifier] NOT NULL, [ContainerId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Item] PRIMARY KEY ( [ContainerId] ASC, [ItemId] ASC ) ) CREATE TABLE [Property] ( [ContainerId] [uniqueidentifier] NOT NULL, [PropertyId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Property] PRIMARY KEY ( [ContainerId] ASC, [PropertyId] ASC ) ) CREATE TABLE [Item_Property] ( [ContainerId] [uniqueidentifier] NOT NULL, [ItemId] [uniqueidentifier] NOT NULL, [PropertyId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Item_Property] PRIMARY KEY ( [ContainerId] ASC, [ItemId] ASC, [PropertyId] ASC ) ) CREATE TABLE [Container_Property] ( [ContainerId] [uniqueidentifier] NOT NULL, [PropertyId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Container_Property] PRIMARY KEY ( [ContainerId] ASC, [PropertyId] ASC ) ) The existing domain model has the following class structure: The Property class contains other members representing the property's name and value. The ContainerProperty and ItemProperty classes have no additional members. They exist only to identify the owner of the Property. The Container and Item classes have methods that return collections of ContainerProperty and ItemProperty respectively. Additionally, the Container class has a method that returns a collection of all of the Property objects in the object graph. My best guess is that this was either a convenience method or a legacy method that was never removed. The business logic mainly works with Item (as the aggregate root) and only works with a Container when adding or removing Items. I have tried several techniques for mapping this but none work so I won't include them here unless someone asks for them. How would you map this?

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  • Hibernate naturalID

    - by DD
    Hibernate doesnt seem to generate a notnull constraint on a field I marked as naturalID. Is this normal? @MappedSuperclass public class AbstractDomainObject extends PersistentObject { @NaturalId private String code; DB Schema: CONSTRAINT SYS_CT_47 UNIQUE(CODE) There is no not null constraint here.

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  • Foreign Keys and Primary Keys at the same time

    - by Bader
    hello , i am trying to create table (orderdetails) , the table has two FKs and PKs at the same keys here is my code create table OrderDetails2 ( PFOrder_ID Number(3) PFProduct_ID Number(3) CONSTRAINT PF PRIMARY KEY (PFOrder_ID,PFProduct_ID), CONSTRAINT FK_1 FOREIGN KEY (PFProudct_ID) REFERENCES Product(Product_ID), CONSTRAINT FK_2 FOREIGN KEY (PFOrder_ID) REFERENCES Orderr(Order_ID) ); i am using Oracle express , a problem pops when i run the code , here is it ORA-00907: missing right parenthesis what is the problem ?

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  • foreign key and index issue

    - by George2
    Hello everyone, I am using SQL Server 2008 Enterprise. I have a table and one of its column is referring to another column in another table (in the same database) as foreign key, here is the related SQL statement, in more details, column [AnotherID] in table [Foo] refers to another table [Goo]'s column [GID] as foreign key. [GID] is primary key and clustered index on table [Goo]. My question is, in this way, if I do not create index on [AnotherID] column on [Foo] explicitly, will there be an index created automatically for [AnotherID] column on [Foo] -- because its foreign key reference column [GID] on table [Goo] already has primary clustered key index? CREATE TABLE [dbo].[Foo]( [ID] [bigint] IDENTITY(1,1) NOT NULL, [AnotherID] [int] NULL, [InsertTime] [datetime] NULL CONSTRAINT DEFAULT (getdate()), CONSTRAINT [PK_Foo] PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] ALTER TABLE [dbo].[Foo] WITH CHECK ADD CONSTRAINT [FK_Foo] FOREIGN KEY([Goo]) REFERENCES [dbo].[Goo] ([GID]) ALTER TABLE [dbo].[Foo] CHECK CONSTRAINT [FK_Foo] thanks in advance, George

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  • Keeping User-Input UITextVIew Content Constrained to Its Own Frame

    - by siglesias
    Trying to create a large textbox of fixed size. This problem is very similar to the 140 character constraint problem, but instead of stopping typing at 140 characters, I want to stop typing when the edge of the textView's frame is reached, instead of extending below into the abyss. Here is what I've got for the delegate method. Seems to always be off by a little bit. Any thoughts? - (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text { BOOL edgeBump = NO; CGSize constraint = textView.frame.size; CGSize size = [[textView.text stringByAppendingString:text] sizeWithFont:textView.font constrainedToSize:constraint lineBreakMode:UILineBreakModeWordWrap]; CGFloat height = size.height; if (height > textView.frame.size.height) { edgeBump = YES; } if([text isEqualToString:@"\b"]){ return YES; } else if(edgeBump){ NSLog(@"EDGEBUMP!"); return NO; } return YES; } EDIT: As per Max's suggestion below, here is the code that works: - (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text { CGSize constraint = textView.frame.size; NSString *whatWasThereBefore = textView.text; textView.text = [textView.text stringByReplacingCharactersInRange:range withString:text]; if (textView.contentSize.height >= constraint.height) { textView.text = whatWasThereBefore; } return NO; }

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  • Microsoft Access - Enter Parameter Value why?

    - by Jane Doe
    I am encountering a problem for my database. Here is the relationships of the database And tried to do the query for how many transactions have movie "Harry_Potter"? so I used SQL query: SELECT COUNT(td.movie) AS number_of_occurrence, td.transaction_number FROM TransactionDetails td, MovieDetails md WHERE md.movie = Harry_Potter But it asks for Harry_Potter enter parameter value why? The relevant SQL statements are CREATE TABLE TransactionDetails ( transaction_number INTEGER PRIMARY KEY, movie VARCHAR(30) NOT NULL, date_of_transaction DATE NOT NULL, member_number INTEGER NOT NULL ) CREATE TABLE MovieDetails ( movie VARCHAR(30) PRIMARY KEY, movie_type VARCHAR(3) NOT NULL, movie_genre VARCHAR(10) NOT NULL ) ALTER TABLE TransactionDetails ADD CONSTRAINT member_number_fk FOREIGN KEY (member_number) REFERENCES LimelightMemberDetails(member_number); ALTER TABLE TransactionDetails ADD CONSTRAINT transaction_number_drink_fk FOREIGN KEY (transaction_number) REFERENCES DrinkTransactionDetails(transaction_number); ALTER TABLE TransactionDetails ADD CONSTRAINT transaction_number_food_fk FOREIGN KEY (transaction_number) REFERENCES FoodTransactionDetails(transaction_number); ALTER TABLE TransactionDetails ADD CONSTRAINT movie_fk FOREIGN KEY (movie) REFERENCES MovieDetails (movie); Thank you for your help! If there is anything wrong with my database design please let me know! thank you!

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  • Update database schema with hibernate

    - by blow
    Hi all, with <property name="hibernate.hbm2ddl.auto">update</property> i can create my database schema, it automatically add properties, constraint, key etc... But what about UPDATE the database schema? If i remove some property from my entities, hibernate doesn't remove it, or if i change some constraint, hibernate doesn't touch constraint already created... So, there is a way to make hibernate really update the database schema? Thanks.

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  • Hi i have a c programming doubt in the implementation of hash table?

    - by aks
    Hi i have a c programming doubt in the implementation of hash table? I have implemented the hash table for storing some strings? I am having problem while dealing with hash collisons. I am following chaining link-list approach to overcome the same? But, somehow my code is behaving differently. I am not able to debug the same? Can somebody help? This is what i am facing: Say first time, i insert a string called gaur. My hash map calculates the index as 0 and inserts the string successfully. However, when another string whose hash map also when calculates turns out to be 0, my previous value gets overrridden i.e. gaur will be replaced by new string. This is my code: struct list { char *string; struct list *next; }; struct hash_table { int size; /* the size of the table */ struct list **table; /* the table elements */ }; struct hash_table *create_hash_table(int size) { struct hash_table *new_table; int i; if (size<1) return NULL; /* invalid size for table */ /* Attempt to allocate memory for the table structure */ if ((new_table = malloc(sizeof(struct hash_table))) == NULL) { return NULL; } /* Attempt to allocate memory for the table itself */ if ((new_table->table = malloc(sizeof(struct list *) * size)) == NULL) { return NULL; } /* Initialize the elements of the table */ for(i=0; i<size; i++) new_table->table[i] = '\0'; /* Set the table's size */ new_table->size = size; return new_table; } unsigned int hash(struct hash_table *hashtable, char *str) { unsigned int hashval = 0; int i = 0; for(; *str != '\0'; str++) { hashval += str[i]; i++; } return (hashval % hashtable->size); } struct list *lookup_string(struct hash_table *hashtable, char *str) { printf("\n enters in lookup_string \n"); struct list * new_list; unsigned int hashval = hash(hashtable, str); /* Go to the correct list based on the hash value and see if str is * in the list. If it is, return return a pointer to the list element. * If it isn't, the item isn't in the table, so return NULL. */ for(new_list = hashtable->table[hashval]; new_list != NULL;new_list = new_list->next) { if (strcmp(str, new_list->string) == 0) return new_list; } printf("\n returns NULL in lookup_string \n"); return NULL; } int add_string(struct hash_table *hashtable, char *str) { printf("\n enters in add_string \n"); struct list *new_list; struct list *current_list; unsigned int hashval = hash(hashtable, str); printf("\n hashval = %d", hashval); /* Attempt to allocate memory for list */ if ((new_list = malloc(sizeof(struct list))) == NULL) { printf("\n enters here \n"); return 1; } /* Does item already exist? */ current_list = lookup_string(hashtable, str); if (current_list == NULL) { printf("\n DEBUG Purpose \n"); printf("\n NULL \n"); } /* item already exists, don't insert it again. */ if (current_list != NULL) { printf("\n Item already present...\n"); return 2; } /* Insert into list */ printf("\n Inserting...\n"); new_list->string = strdup(str); new_list->next = NULL; //new_list->next = hashtable->table[hashval]; if(hashtable->table[hashval] == NULL) { hashtable->table[hashval] = new_list; } else { struct list * temp_list = hashtable->table[hashval]; while(temp_list->next!=NULL) temp_list = temp_list->next; temp_list->next = new_list; hashtable->table[hashval] = new_list; } return 0; }

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