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  • Duplicate Symbol Linker Error (C++ help)

    - by Vash265
    Hi. I'm learning some CSP (constraint satisfaction) theory stuff right now, and am using this library to parse XML files. I'm using Xcode as an IDE. My program compiles fine, but when it goes to link the files, I get a duplicate symbol error with the XMLParser_libxml2.hh file. My files are separated as such: A class header file that includes the XMLParser file above A class implementation file that include the class header file A main file that includes the class header file The duplicate symbol is occurring in main.o and classfile.o, but as far as I can tell, I'm not actually adding that .hh file twice. Full error: ld: duplicate symbol bool CSPXMLParser::UTF8String::to<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::basic_string<char, std::char_traits<char>, std::allocator<char> >&) constin /Users/vash265/CSP/Untitled/build/Untitled.build/Debug/Untitled.build/Objects-normal/x86_64/dStructFill.o and /Users/vash265/CSP/Untitled/build/Untitled.build/Debug/Untitled.build/Objects-normal/x86_64/main.o Copying the implementation of the class into the main file and taking the class implementation file out of the compilation target alleviates the error, but it's a disorganized mess this way, and I'll be adding more classes very soon (and it would be nice to have them in separate files). As I've come to understand it, this is caused by the file (XMLParser_libxml2.hh) having both the class and function definition and implementation in one file (and it seems as though this might have been necessary due to the use of templates in that 'header' file). Any ideas on how to get around sticking all my class files in my main.cpp? (I've tried ifdefs, they don't work).

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  • Perfect hash in Scala.

    - by Lukasz Lew
    I have some class C: class C (...) { ... } I want to use it to index an efficient map. The most efficient map is an Array. So I add a "global" "static" counter in companion object to give each object unique id: object C { var id_counter = 0 } In primary constructor of C, with each creation of C I want to remember global counter value and increase it. Question 1: How to do it? Now I can use id in C objects as perfect hash to index array. But array does not preserve type information like map would, that a given array is indexed by C's id. Question 2: Is it possible to have it with type safety?

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  • Efficiently retrieve objects with one to many references in Grails using GORM

    - by bebeastie
    I'm trying to determine how to find/retrieve/load objects efficiently in terms of a.) minimizing calls to database and b.) keeping the code as elegant/simple as possible (i.e. not writing hql etc.). Assume you have two objects: public class Foo { Bar bar String badge } public class Bar { String name } Each Foo has a bar and a badge. Also assume that all badges are unique within a bar. So if a Foo has a badge "4565" there are no other Foos that have the same badge # AND the same bar. If I have a bar ID, how can I efficiently retrive the Foo w/o first selecting Bar? I know I can do this: Foo.findByBadgeAndBar("4565", Bar.findById("1")) But that seems to cause a select on the Bar table followed by a select on the Foo table. In other words, I need to produce the Grails/Hibernate/GORM equivalent of the following: select * from foo where badge="4565" and bar_id="1"

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  • A "smart" (forgiving) date parser?

    - by jdmuys
    I have to migrate a very large dataset from one system to another. One of the "source" column contains a date but is really a string with no constraint, while the destination system mandates a date in the format yyyy-mm-dd. Many, but not all, of the source dates are formatted as yyyymmdd. So to coerce them to the expected format, I do (in Perl): return "$1-$2-$3" if ($val =~ /(\d{4})[-\/]*(\d{2})[-\/]*(\d{2})/); The problem arises when the source dates moves away from the "generic" yyyymmdd. The goal is to salvage as many dates as possible, before giving up. Example source strings include: 21/3/1998, March 2004, 2001, 3/4/97 I can try to match as many of the examples I can find with a succession of regular expressions such as the one above. But is there something smarter to do? Am I not reinventing the wheel? Is there a library somewhere doing something similar? I couldn't find anything relevant googling "forgiving date parser". (any language is OK).

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  • Should I use integer primary IDs?

    - by arthurprs
    For example, I always generate an auto-increment field for the users table, but I also specify a UNIQUE index on their usernames. There are situations that I first need to get the userId for a given username and then execute the desired query, or use a JOIN in the desired query. It's 2 trips to the database or a JOIN vs. a varchar index. Should I use integer primary IDs? Is there a real performance benefit on INT over small VARCHAR indexes?

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  • PHP/MYSQL Year Month table for news archive

    - by ee12csvt
    Hi all, I am creating a news archive for my site and want to create an overview page from the following DB table id - Unique identifier newsDate - in a format XXXX-XX-XX title - News Item title details - News item photo - News Item Photo caption - News Item Photo caption update - Timestamp for record The news on the site is current but I hope to add some data from years gone by over the next few months and years. What I want to do is create a new line for each year and highlight the month which corresponds to a record in the DB table, similar to that below. 2002 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2004 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2005 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2008 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Any help or advice would be much appreciated Cheers

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  • AWS Load Balancer with a static IP address

    - by user965904
    I have a set-up running on Amazon cloud with a couple of EC2 Instances running through a load balancer. It is important that the site has a unique(static) IP or set of IPs as I'm plugging in 3rd party APIs which only accept requests made from IPs which have been added to their whitelist. So basically unless we can give these 3rd parties a static IP or range of IPs that the requests from the site will always come from then we would be unable to make any calls to them. Anyone knows how to achieve this as I know that Elastic IPs are not compatible with load balancers? If I were to look up the IP of the load balancer DNS name (e.g. dualstack.awseb-BAMobile-ENV-xxxxxxxxx.eu-west-1.elb.amazonaws.com resolves to 200.200.200.200) would that IP be Static? Any help/advise is greatly appreciated guys.

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  • How to add a sequence column to an existing table with records

    - by user1888543
    I had created a new table named USERLOG with two fields from a previous VIEW. The table already consist of about 9000 records. The two fields taken from the VIEW, i.e. weblog_views consist of IP (consists of IP address), and WEB_LINK (consists of URL). This is the code I used, CREATE TABLE USERLOG AS SELECT C_IP, WEB_LINK FROM weblog_views; I want to add another column to this table called the USER_ID, which would consists of a sequence starting with 1 to 9000 records to create a unique id for each existing rows. I need help with this part. I'm using Oracle SQL Developer: ODMiner version 3.0.04. I tried using the AUTO-INCREMENT option, ALTER TABLE USERLOG ADD USER_ID INT UNSIGNED NOT NULL AUTO_INCREMENT; But I get an error with this, Error report: SQL Error: ORA-01735: invalid ALTER TABLE option 01735. 00000 - "invalid ALTER TABLE option" So, I would really appreciate any help that I can get!

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  • What are the advantages of learning Go?

    - by Pangea
    What is so unique about Go? Over the 11 years of my career I've learnt Pascal, C, C++, COBOL and then Java. I always felt that going from C to C++ to Java was a incremental and value added progression. Now I see a proliferation of functional programming languages and I understand the benefit of learning few of them (like actors in scala etc). Now I was going through the Go programming language and was wondering why would I want to learn this? Is this going to simplify how I have been writing the code? What are its use cases? How can I make a case to promote it in my team? What is the next programming language that a Java team that builds business applications like us can benefit from? Appreciate your comments on this.

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  • How to organise a php based website

    - by bsandrabr
    I am putting my php /mysql website up and this is my scenario The users are grouped into sites each site with their own unique database. There will be about 40 users per site. the two options I'm trying to decide between are have a central website running the php and directing the users off to their own database using sub domains for each user each with their own php in htdocs I dont even know if 2 is possible/stupid but if it was, would it make any difference to performance as they're all being run by the same server. Any other ideas/ advice much appreciated as I want to organise it the best way from the start

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  • How to find an embedded platform?

    - by gmagana
    I am new to the locating hardware side of embedded programming and so after being completely overwhelmed with all the choices out there (pc104, custom boards, a zillion option for each board, volume discounts, devel kits, ahhh!!) I am asking here for some direction. Basically, I must find a new motherboard and (most likely) re-implement the program logic. Rewriting this in C/C++/Java/C#/Pascal/BASIC is not a problem for me. so my real problem is finding the hardware. This motherboard will have several other devices attached to it. Here is a summary of what I need to do: Required: 2 RS232 serial ports (one used all the time for primary UI, the second one not continuous) 1 modem (9600+ baud ok) [Modem will be in simultaneous use with only one of the serial port devices, so interrupt sharing with one serial port is OK, but not both] Minimum permanent/long term storage: Whatever O/S requires + 1 MB (executable) + 512 KB (Data files) RAM: Minimal, whatever the O/S requires plus maybe 1MB for executable. Nice to have: USB port(s) Ethernet network port Wireless network Implementation languages (any O/S I will adapt to): First choice Java/C# (Mono ok) Second choice is C/Pascal Third is BASIC Ok, given all this, I am having a lot of trouble finding hardware that will support this that is low in cost. Every manufacturer site I visit has a lot of options, and it's difficult to see if their offering will even satisfy my must-have requirements (for example they sometimes list 3 "serial ports", but it appears that only one of the three is RS232, for example, and don't mention what the other two are). The #1 constraint is cost, #2 is size. Can anyone help me with this? This little task has left me thinking I should have gone for EE and not CS :-). EDIT: A bit of background: This is a system currently in production, but the original programmer passed away, and the current hardware manufacturer cannot find hardware to run the (currently) DOS system, so I need to reimplement this in a modern platform. I can only change the programming and the motherboard hardware.

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  • How to set different colors to the bars in stacked bar chart in ireport ?

    - by Purushotham
    Hi, I need to set a unique color to each bar in the stacked bar chart. Whatever the color I see in one bar it shouldn't be repeated in any other bar or any other stack. For example: I have 5 bars in the report. Each bar has 3 different stacks. I want to apply a red related colors to the first bar and its stacks. Second bar should have blue related colors. etc.. It is showed in the attached image. The image shows a very basic requirement what we want. Just created using a normal ms paint. Stacked Bar MS Paint Image

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  • Need a Count, but Multiple other fields

    - by user3727752
    I have a table that looks like this: person trip_id date home destination joe 1 3/10 chicago new york joe 2 4/10 chicago l.a. joe 3 5/10 chicago boston luther 4 3/12 new york chicago luther 5 3/18 new york boston I want to get a result like person trips firstDate home joe 3 3/10 chicago luther 2 3/12 new york Currently I've got Select person, count(trip_id) as trips, min(date) as firstDate from [table] group by person order by firstDate I can't figure out how to get home in there as well. Home is always unique to the person. But my DBMS doesn't know that. Is there an easy way around this problem? Appreciate it.

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  • Lucene Analyzer to Use With Special Characters and Punctuation?

    - by Brandon
    I have a Lucene index that has several documents in it. Each document has multiple fields such as: Id Project Name Description The Id field will be a unique identifier such as a GUID, Project is a user's ProjectID and a user can only view documents for their project, and Name and Description contain text that can have special characters. When a user performs a search on the Name field, I want to be able to attempt to match the best I can such as: First Will return both: First.Last and First.Middle.Last Name can also be something like: Test (NameTest) Where, if a user types in 'Test', 'Name', or '(NameTest)', then they can find the result. However, if I say that Project is 'ProjectA' then that needs to be an exact match (case insensitive search). The same goes with the Id field. Which fields should I set up as Tokenized and which as Untokenized? Also, is there a good Analyzer I should consider to make this happen? I am stuck trying to decide the best route to implement the desired searching.

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  • Hibernate not using schema and catalog name in id generation with strategy increment

    - by Ben
    Hi, I am using the hibernate increment strategy to create my IDs on my entities. @GenericGenerator(name="increment-strategy", strategy="increment") @Id @GeneratedValue(generator="increment=strategy") @Column(name="HDR_ID", unique=true, nullable=false) public int getHdrId(){ return this.hdrId; } The entity has the following table annotation @Table(name = "PORDER.PUB.PO_HEADER", schema = "UVOSi", catalog = "VIRT_UVOS") Please note I have two datasources. When I try to insert an entity Hibernate creates the following SQL statement: select max(hdr_id) from PORDER.PUB.PO_HEADER which causes the following error: Group specified is ambiguous, resubmit the query by fully qualifying group name. When I create a query by hand with entityManager.createQuery() hibernate uses the fully qualified name select XXX from VIRT_UVOS.UVOSi.PORDER.PUB.PO_HEADER and that works fine. So how do I get Hibernate to use the fully qualified name in the Id autogeneration? Btw. I am using Hibernate 3.2 and Seam 2.2 running on JBoss 4.2.3 Regards Immo

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  • Smarty iteration: is there a similar function when not in a foreach loop?

    - by Kyle Sevenoaks
    Hi, I'm trying to add a JS fly to basket plugin to the site I'm working on, but the plugin needs unique productID numbers, is there a way to iterate this in Smarty when not in a foreach loop? Something like: {$smarty.foreach.foo.iteration} Here's the code I need to itrate: <span id="slidingProd57404045"> <a href="{link controller=order action=addToCart id=$product.ID returnPath=true}" rel="nofollow" class="addToCart" title="Bestill" onclick="addToBasket(57404045); return false;" id="fly_to_basket">&nbsp;</a> </span> The 57404045 needs to be iterated. Thanks.

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  • Questions about my program and Polymorphism

    - by Strobe_
    Ok, so basically I'm creating a program which allows the user to select a shape (triangle, square, circle) and then it takes in a int and calculates the boundary length and area. I have no problem doing this and have a program that's working perfectly. (https://gist.github.com/anonymous/c63a03c129560a7b7434 4 classes) But now I have to implement this with polymorphism concepts and I'm honestly struggling as to how to do it. I have a basic idea of what I want to do when it comes to inheritance Main | Shapes / | \ triangle circle square But I don't understand how I'm supposed to override when all the methods within the triangle/square/circle classes are unique, there are no "abstract" methods as such that I could inherit from the "Shapes" class. If somebody could make look quickly at the code I linked and suggest a way to do this it would be much appreciated. Sorry if I was bad at explaining this. Thanks.

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  • document.getElementByID - checking whether an element has been found or not

    - by be here now
    Hi, guys. Here's a sample code, that opens an internet explorer window, navigates to google, and gets some element on the page by its unique id: set ie = CreateObject("InternetExplorer.Application") ie.navigate("www.google.com") ie.visible = true while ie.readystate <> 4 wscript.sleep 100 WEnd set some_object = ie.document.getelementbyid("xjsc") MsgBox some_object.tagname, 0 This sample brings me a DIV popup, which satisfies me completely. But at the next step I'd like to check whether some id exists in the page, or not. Unfortunately, I can't just be, like, set some_object = ie.document.getelementbyid("some_non_existant_id") if some_object.tagname = "" then ... because it gives me the following error: ie.vbs(12, 1) Microsoft VBScript runtime error: Object required: 'some_object' So, what's the best practice to check whether an element has been found or not?

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  • Ajax: Load XML from different domain?

    - by John Isaacks
    I have signed up(paid) for Google site search. They have me a url of a sort of web service where I can send a query to it, it searches my site, and it returns XML of the search results. Well I am trying to load this XML via Ajax from a page on my site but I cannot. I can load from any of my pages on my domain so I am assuming it is because of the XML being on Google's domain. So there has got to be a way to load it though, I don't think they would have given me the URL if I couldn't do anything with it lol. Does anyone know how to do this? Thanks! UPDATE: this is what the page says on google that gave me the XML: How to get XML You can get XML results for your search engine by replacing query+terms with your search query in this URL: http://www.google.com/cse?cx=MY_UNIQUE_KEY&client=google-csbe&output=xml_no_dtd&q=query+terms Where MY_UNIQUE_KEY = my unique key.

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  • Zip up groups of webpages for viewing in the browser

    - by Arlen Beiler
    I think there should be a standard for saving and viewing bunches of webpages as a website. For instance, say I have a whole bunch of pages, such as I get from the WordPress plugin "Really Static" (which saves the entire site), and I have all the links start with a slash (to make linking to supporting files easier). Now, I can't really use those links if I am reading it from the file system. If there would be a standard where we could zip up files, give them a unique extension (like "hzip" for html zip), and open the file with any browser, which would display it as though the root of that file were the root of the pages. "file://examplefile.hzip/" The links would then all work. This would really help sharing and copying groups of webpages. Is this a good idea? A bad one? What do you think?

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  • Problem with auto increment primary key (MySQL).

    - by mathon12
    I have 2 tables each using other's primary key as a foreign key. The primary keys for both are set to auto_increment. The problem is, when I try to create and entry into one of the tables, I have no idea what the primary key of the entry is and can't figure out what to put in the other table as a foreign key. What should I do? Do I drop auto_increment altogether and cook up a unique identifier for each entry so I can use it to address the created entries? I'm using PHP, if that's relevant. Thanks.

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  • Two entities with @ManyToOne should join the same table

    - by Ivan Yatskevich
    I have the following entities Student @Entity public class Student implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Teacher @Entity public class Teacher implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Task @Entity public class Task implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "student_id") }) private Student author; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "teacher_id") }) private Teacher curator; //getters and setters } Consider that author and curator are already stored in DB and both are in the attached state. I'm trying to persist my Task: Task task = new Task(); task.setAuthor(author); task.setCurator(curator); entityManager.persist(task); Hibernate executes the following SQL: insert into student_task (teacher_id, id) values (?, ?) which, of course, leads to null value in column "student_id" violates not-null constraint Can anyone explain this issue and possible ways to resolve it?

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  • Top 3 Max entries for a Combination which a condition

    - by Asharmb
    I am new to sql side. so if this questoin sound very easy then please spare me. I have a 4 coloumns in a sql table.Let say A,B,C,D . For any BC combination I may get any number of rows. I need to get at max 3 rows (which inturn give me 3 unique value of A for that BC ombination) for these selected rows i should have Top 3 Max value of D. As compare to other entries for that BC combination. So there can be any number of BC combination so the above logic should imply to all of them.

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  • Could someone give me their two cents on this optimization strategy

    - by jimstandard
    Background: I am writing a matching script in python that will match records of a transaction in one database to names of customers in another database. The complexity is that names are not unique and can be represented multiple different ways from transaction to transaction. Rather than doing multiple queries on the database (which is pretty slow) would it be faster to get all of the records where the last name (which in this case we will say never changes) is "Smith" and then have all of those records loaded into memory as you go though each looking for matches for a specific "John Smith" using various data points. Would this be faster, is it feasible in python, and if so does anyone have any recommendations for how to do it?

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  • Exceptions in ASP.MVC

    - by George
    Hello guys, I'm here again with another question about MVC. Here is the deal. I have a simple table/class with an Id and a Name. Names suppossed to be unique, and are modeled like that in the DB. I created my controller and everything just works fine. But if I try to insert a name that already exists, an exception should be thrown. I'm just not finding what is the correct kind of exception and it's namespace. The error must be coming from the DB, so... Any ideas? Thanks

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