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  • How should I progressively enhance this content with JavaScript?

    - by Sean Dunwoody
    The background to this problem is that I'm doing a computing project which involves Some drop down boxes for input, and a text input where the user can input a date. I've used YUI to enhance the form, so the calendar input uses the YUI calendar widget and the drop down list is converted into a horizontal list of inputs where the user only has to click once to select any input as opposed to two clicks with the drop down box (hope that makes sense, not sure how to explain it clearly) The problem is, that in the design section of my project I stated that I would follow the progressive enhancement principles. I am struggling however to ensure that users without JavaScript are able to view the drop down box / text input on said page. This is not because I do not necessarily know how, but the two methods I've tried seem unsatisfactory. Method 1 - I tried using YUI to hide the text box and drop down list, this seemed like the ideal solution however there was quite a noticeable lag when loading the page (especially for the first time), the text box and drop down list where visibile for at least a second. I included the script for this just before the end of the body tag, is there any way that I can run it onload with YUI? Would that help? Method 2 - Use the noscript tag . . . however I am loathed to do this as while it would be a simple solution, I have read various bad things about the noscript tag. Is there a way of making mehtod one work? Or is there a better way of doing this that I am yet to encounter?

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  • How to create an AST with ANTLR from a hierarchical key-value syntax

    - by Brabster
    I've been looking at parsing a key-value data format with ANTLR. Pretty straightforward, but the keys represent a hierarchy. A simplified example of my input syntax: /a/b/c=2 /a/b/d/e=3 /a/b/d/f=4 In my mind, this represents a tree structured as follows: (a (b (= c 2) (d (= e 3) (= f 4)))) The nearest I can get is to use the following grammar: /* Parser Rules */ start: (component NEWLINE?)* EOF -> (component)*; component: FORWARD_SLASH ALPHA_STRING component -> ^(ALPHA_STRING component) | FORWARD_SLASH ALPHA_STRING EQUALS value -> ^(EQUALS ALPHA_STRING value); value: ALPHA_STRING; /* Lexer Rules */ NEWLINE : '\r'? '\n'; ALPHA_STRING : ('a'..'z'|'A'..'Z'|'0'..'9')+; EQUALS : '='; FORWARD_SLASH : '/'; Which produces: (a (b (= c 2))) (a (b (d (= e 3)))) (a (b (d (= f 4)))) I'm not sure whether I'm asking too much from a generic tool such as ANTLR here, and this is as close I can get with this approach. That is, from here I consume the parts of the tree and create the data structure I want by hand. So - can I produce the tree structure I want directly from a grammar? If so, how? If not, why not - is it a technical limitation in ANTLR or is it something more CS-y to do with the type of language involved?

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  • Parsing every part of an HTTP header field-value

    - by brickner
    Hi all. I'm parsing HTTP data directly from packets (either TCP reconstructed or not, you can assume it is). I'm looking for the best way to parse HTTP as accurately as possible. The main issue here is the HTTP header. Looking at the basic RFC of HTTP/1.1, it seems that HTTP header parsing would be complex. The RFC describes very complex regular expressions for different parts of the header. Should I write these regular expressions to parse the different parts of the HTTP header? The basic parsing I've written so far for HTTP header is for the generic HTTP header: message-header = field-name ":" [ field-value ] And I've included replacing inner LWS with SP and repeating headers with the same field-name with comma separated values as described in section 4.2. However, looking at section 14.9 for example would show that in order to parse the different parts of the field-value I need a much more complex parsing scheme. How do you suggest I should handle the complex parts of HTTP parsing (specifically the field-value) assuming I want to give the parser users the full capabilities of HTTP and to parse every part of HTTP? Design suggestions for this would also be appreciated. Thanks.

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  • Generating SQL change scripts in SSMS 2008

    - by Munish Goyal
    I have gone through many related SO threads and got some basic info. Already generated DB diagram. After that i am unable to find a button/option to generate SQL scripts (create) for all the tables in diagram. "Generate script" button is disabled, even on clicking the table in diagram. However i enabled the auto-generate option in tools-designer. But what to do with previous diagrams. I just want an easy way to auto-generate such scripts (create/alter) and would be gud if i get auto-generated stored procs for insert/selects/update etc. EDIT: I could do generate scripts for DB objects. Now: 1. How to import DB diagram from another DB. 2. How to generate (and manage their change integrated with VS source control) routine stored-procs like insert, update and select. Ok let me ask another way, can experts guide on the usual flow of creating/altering tables (across releases), creating stored-procs (are stored-procs the best way to go ?) and their change-management using SSMS design tools and minimal effort ?

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  • How to embed XBase expressions in an Xtext DSL

    - by Marcus Mathioudakis
    I am writing a simple little DSL for specifying constraints on messages, and Have been trying without success for a while to embed XBase expressions into the language. The Grammar looks like this: grammar org.xtext.businessrules.BusinessRules with org.eclipse.xtext.xbase.Xbase //import "http://www.eclipse.org/xtext/xbase/Xbase" as xbase import "http://www.eclipse.org/xtext/common/JavaVMTypes" as jvmTypes generate businessRules "http://www.xtext.org/businessrules/BusinessRules" Start: rules+=Constraint*; Constraint: {Constraint} 'FOR' 'PAYLOAD' payload=PAYLOAD 'ELEMENT' element=ID 'CONSTRAINED BY' constraint=XExpression; PAYLOAD: "SimulationSessionEvents" |"stacons" |"any" ; Range: 'above' min=INT ('below' max=INT)? |'below' max=INT ('above' min=INT)? ; When trying to parse a file such as: FOR PAYLOAD SimulationSessionEvents ELEMENT matrix CONSTRAINED BY ... I can't get it to work for ... = any kind of Arithmetic expression, although it works for ...= loop or if expression, or even just a number. As soon as I do something like '-5' or '4-5' it says Couldn't resolve reference to JvmIdentifiableElement '-', even though the Xbase.xtext Grammar looks like it allows these expressions. I don't think I'm missing any Jars, as it doesn't complain when I run the mwe workflow, but only when trying to parse the input file. Any help would be much appreciated.

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  • How to cache pages using background jobs ?

    - by Alexandre
    Definitions: resource = collection of database records, regeneration = processing these records and outputting the corresponding html Current flow: Receive client request Check for resource in cache If not in cache or cache expired, regenerate Return result The problem is that the regeneration step can tie up a single server process for 10-15 seconds. If a couple of users request the same resource, that could result in a couple of processes regenerating the exact same resource simultaneously, each taking up 10-15 seconds. Wouldn't it be preferrable to have the frontend signal some background process saying "Hey, regenerate this resource for me". But then what would it display to the user? "Rebuilding" is not acceptable. All resources would have to be in cache ahead of time. This could be a problem as the database would almost be duplicated on the filesystem (too big to fit in memory). Is there a way to avoid this? Not ideal, but it seems like the only way out. But then there's one more problem. How to keep the same two processes from requesting the regeneration of a resource at the same time? The background process could be regenerating the resource when a frontend asks for the regeneration of the same resource. I'm using PHP and the Zend Framework just in case someone wants to offer a platform-specific solution. Not that it matters though - I think this problem applies to any language/framework. Thanks!

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  • Where to Store ID Field In Silverlight

    - by Blake Blackwell
    I am trying to use the MVVM pattern, and I am wondering where I place an ID value. Do I create a TextBlock that has its visibility property set to collapsed? Or is there a better place to store this kind of data? Currently the command parameter is set to: CommandParameter="{Binding ElementName=Name,Path=Text}" But I'd rather it be something like: CommandParameter="{Binding ElementName=Id,Path=Text}" I'm totally up for suggestions on what the best way there is to do this, since I'm new to this pattern and presentation language. <ListBox x:Name="MyListBox" ItemsSource="{Binding MyData, Mode=TwoWay}" BorderThickness="0"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <CheckBox x:Name="Visible" IsChecked="{Binding Visible, Mode=TwoWay}" Command="{Binding ElementName=MyListBox, Path=DataContext.MyCommand}" CommandParameter="{Binding ElementName=Name,Path=Text}" /> <TextBlock Text="{Binding Name}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> EDIT: Option 1 <CheckBox x:Name="Visible" IsChecked="{Binding Visible, Mode=TwoWay}" Command="{Binding ElementName=MyListBox, Path=DataContext.MyCommand}" CommandParameter="{Binding Id}" /> This option gives me just the Id, which is useful in many situations. EDIT: Option 2 <CheckBox x:Name="Visible" IsChecked="{Binding Visible, Mode=TwoWay}" Command="{Binding ElementName=MyListBox, Path=DataContext.MyCommand}" CommandParameter="{Binding}" /> This option gives me the full model, which is even useful for my particular situation.

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  • C# - Naming a value combined "getter/setter" method (WebForms & Binding)

    - by tyndall
    Looking for some help on some names for a project I'm currently working on. I don't have a compsci degree so I don't know what to call this. I have a method called TryToGetSetValue(Direction direction, object value, object valueOnFail) Then there would be a Direction enum public enum Direction { ModelToForm, FormToModel } Background This is a legacy ASP.NET application. The models, database, and mainframe are designed poorly. I can't put in MVP or MVC patterns yet (too much work). ASP.NET code is a ridiculous mess (partial pages, single-page design, 5x the normal amount of jQuery, everything is a jQuery UI dialog). I'm just trying to put in a bridge so then I can do more refactoring over the next year. I have ~200 fields that need to be set on a GET and written back on a POST. I trying not to x2 these 200 fields and have 400 lines of code to support. What would you call my method? enum? Is there so other form of binding that would be easy to use instead? I'm not a fan of the DetailsView or FormView built-ins of ASP.NET WebForms.

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  • Image Grabbing with False Referer

    - by Mr Carl
    Hey guys, I'm struggling with grabbing an image at the moment... sounds silly, but check out this link :P http://manga.justcarl.co.uk/A/Oishii_Kankei/31/1 If you get the image URL, the image loads. Go back, it looks like it's working fine, but that's just the browser loading up the cached image. The application was working fine before, I'm thinking they implemented some kind of Referer check on their images. So I found some code and came up with the following... $ref = 'http://www.thesite.com/'; $file = 'theimage.jpg'; $hdrs = array( 'http' = array( 'method' = "GET", 'header'= "accept-language: en\r\n" . "Accept:application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*\/*;q=0.5\r\n" . "Referer: $ref\r\n" . // Setting the http-referer "Content-Type: image/jpeg\r\n" ) ); // get the requested page from the server // with our header as a request-header $context = stream_context_create($hdrs); $fp = fopen($imgChapterPath.$file, 'rb', false, $context); fpassthru($fp); fclose($fp); Essentially it's making up a false referrer. All I'm getting back though is a bunch of gibberish (thanks to fpassthru) so I think it's getting the image, but I'm afraid to say I have no idea how to output/display the collected image. Cheers, Carl

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  • When to use certain optimizations such as -fwhole-program and -fprofile-generate with several shared libraries

    - by James
    Probably a simple answer; I get quite confused with the language used in the GCC documentation for some of these flags! Anyway, I have three libraries and a programme which uses all these three. I compile each of my libraries seperately with individual (potentially) different sets of warning flags. However, I compile all three libraries with the same set of optimisation flags. I then compile my main programme linking in these three libraries with its own set of warning flags and the same optimisation flags used during the libraries' compilation. 1) Do I have to compile the libraries with optimisation flags present or can I just use these flags when compiling the final programme and linking to the libraries? If the latter, will it then optimise all or just some (presumably that which is called) of the code in these libraries? 2) I would like to use -fwhole-program -flto -fuse-linker-plugin and the linker plugin gold. At which stage do I compile with these on ... just the final compilation or do these flags need to be present during the compilation of the libraries? 3) Pretty much the same as 2) however with, -fprofile-generate -fprofile-arcs and -fprofile-use. I understand one first runs a programme with generate, and then with use. However, do I have to compile each of the libraries with generate/use etc. or just the final programme? And if it is just the last programme, when I then compeil with -fprofile-use will it also optimise the libraries functionality? Many thanks, James

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  • Voting on Hacker News stories programmatically?

    - by igorgue
    I decided to write an app like: http://michaelgrinich.com/hackernews/ but for Android devices, my idea will use a web application backend (because I rather code in Python and for the web than completely in Java for Android devices). What I have right now implemented is something like this: $ curl -i http://localhost:8080/stories.json?page=1\&stories=1 HTTP/1.0 200 OK Date: Sun, 25 Apr 2010 07:59:37 GMT Server: WSGIServer/0.1 Python/2.6.5 Content-Length: 296 Content-Type: application/json [{"title": "Don\u2019t talk to aliens, warns Stephen Hawking", "url": "http://www.timesonline.co.uk/tol/news/science/space/article7107207.ece?", "unix_time": 1272175177, "comments": 15, "score": 38, "user": "chaostheory", "position": 1, "human_time": "Sun Apr 25 01:59:37 2010", "id": "1292241"}] The next step (and final I think) is voting, my design is doing something like this: $ curl -i http://localhost:8080/stories/1?vote=up -u username:password Will vote up and: $ curl -i http://localhost:8080/stories/1?vote=down -u username:password Down. I have no idea how to do it though... I was planning to use Twill but the login link is always different, e.g.: http://news.ycombinator.com/x?fnid=7u89ccHKln Later the Android app will consume this API. Any experience with programmatically browsing Hacker News?

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  • Java generic Comparable where subclasses can't compare to eachother

    - by dege
    public abstract class MyAbs implements Comparable<MyAbs> This would work but then I would be able to compare class A and B with each other if they both extend MyAbs. What I want to accomplish however is the exact opposite. So does anyone know a way to get the generic type to be the own class? Seemed like such a simple thing at first... Edit: To explain it a little further with an example. Say you have an abstract class animals, then you extend it with Dogs and ants. I wouldn't want to compare ants with Dogs but I however would want to compare one dog with another. The dog might have a variable saying what color it is and that is what I want to use in the compareTo method. However when it comes to ants I would rather want to compare ant's size than their color. Hope that clears it up. Could possibly be a design flaw however.

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  • Session cookie not being created in Rails, very rarely and frustratingly.

    - by James
    Hi everyone, This is an issue sporadically for very few users, however we haven't been able to replicate it. However I have now got a Chrome instance (Mac) which is reproducing the error (for some unknown reason), and I hope to not restart it until I have this nailed! Rails application, using memcached for session store. While the bug manifests in the _app_session_id cookie not being created, our javascript-generated cookie test and app-generated language cookies are being created successfully. This means that 422 / InvalidAuthToken errors are thrown for every form that is submitted by those afflicted - people can't log into the app. The error occurs across all browsers - had reports for IE7 and Firefox (which most users use). Switching to another browser often fixes the issue (though not always), and standard cache-cookie-clear tactics do not. So now that I have got Chrome open which is having the same issue - in development, staging and live environments (meaning http and https). All other browsers are fine. I've restarted the servers and restarted memcached. I don't really want to restart Chrome - in the risk that the issue does go away with that (having said that, it hasn't worked for users). I've been tcpdumping the requests - and although I'll keep digging, I'd love it if anyone had any suggestions, places to start looking, anything. This is really painful ;) Thanks!

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  • What's the best way to select max over multiple fields in SQL?

    - by allyourcode
    The I kind of want to do is select max(f1, f2, f3). I know this doesn't work, but I think what I want should be pretty clear (see update 1). I was thinking of doing select max(concat(f1, '--', f2 ...)), but this has various disadvantages. In particular, doing concat will probably slow things down. What's the best way to get what I want? update 1: The answers I've gotten so far aren't what I'm after. max works over a set of records, but it compares them using only one value; I want max to consider several values, just like the way order by can consider several values. update 2: Suppose I have the following table: id class_name order_by1 order_by_2 1 a 0 0 2 a 0 1 3 b 1 0 4 b 0 9 I want a query that will group the records by class_name. Then, within each "class", select the record that would come first if you ordered by order_by1 ascending then order_by2 ascending. The result set would consist of records 2 and 3. In my magical query language, it would look something like this: select max(* order by order_by1 ASC, order_by2 ASC) from table group by class_name

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  • accessing a value of a nested hash

    - by st
    Hello! I am new to perl and I have a problem that's very simple but I cannot find the answer when consulting my perl book. When printing the result of Dumper($request); I get the following result: $VAR1 = bless( { '_protocol' => 'HTTP/1.1', '_content' => '', '_uri' => bless( do{\(my $o = 'http://myawesomeserver.org:8081/counter/')}, 'URI::http' ), '_headers' => bless( { 'user-agent' => 'Mozilla/5.0 (X11; U; Linux i686; en; rv:1.9.0.4) Gecko/20080528 Epiphany/2.22 Firefox/3.0', 'connection' => 'keep-alive', 'cache-control' => 'max-age=0', 'keep-alive' => '300', 'accept' => 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8', 'accept-language' => 'en-us,en;q=0.5', 'accept-encoding' => 'gzip,deflate', 'host' => 'localhost:8081', 'accept-charset' => 'ISO-8859-1,utf-8;q=0.7,*;q=0.7' }, 'HTTP::Headers' ), '_method' => 'GET', '_handle' => bless( \*Symbol::GEN0, 'FileHandle' ) }, 'HTTP::Server::Simple::Dispatched::Request' ); How can I access the values of '_method' ('GET') or of 'host' ('localhost:8081'). I know that's an easy question, but perl is somewhat cryptic at the beginning. Thank you, St.

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  • How to reuse results with a schema for end of day stock-data

    - by Vishalrix
    I am creating a database schema to be used for technical analysis like top-volume gainers, top-price gainers etc.I have checked answers to questions here, like the design question. Having taken the hint from boe100 's answer there I have a schema modeled pretty much on it, thusly: Symbol - char 6 //primary Date - date //primary Open - decimal 18, 4 High - decimal 18, 4 Low - decimal 18, 4 Close - decimal 18, 4 Volume - int Right now this table containing End Of Day( EOD) data will be about 3 million rows for 3 years. Later when I get/need more data it could be 20 million rows. The front end will be asking requests like "give me the top price gainers on date X over Y days". That request is one of the simpler ones, and as such is not too costly, time wise, I assume. But a request like " give me top volume gainers for the last 10 days, with the previous 100 days acting as baseline", could prove 10-100 times costlier. The result of such a request would be a float which signifies how many times the volume as grown etc. One option I have is adding a column for each such result. And if the user asks for volume gain in 10 days over 20 days, that would require another table. The total such tables could easily cross 100, specially if I start using other results as tables, like MACD-10, MACD-100. each of which will require its own column. Is this a feasible solution? Another option being that I keep the result in cached html files and present them to the user. I dont have much experience in web-development, so to me it looks messy; but I could be wrong ( ofc!) . Is that a option too? Let me add that I am/will be using mod_perl to present the response to the user. With much of the work on mysql database being done using perl. I would like to have a response time of 1-2 seconds.

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  • Getting jQuery datepicker to attach to a TextBox within a ListView

    - by Clay
    I am using the jQuery Datepicker without any problem for TextBox controls that are non-templated. However, I am unable to get the datepicker to work with a TextBox that is in an EditItemTemplate of a ListView control. My latest attempt is to get a handle on this textbox by CSS class name "DateControl", any ideas? <asp:ListVIew id="lvTest" runat="server"> <LayoutTemplate>...</LayoutTemplate> <ItemTemplate>...</ItemTemplate> <EditItemTemplate> <tr> <td> <asp:TextBox ID="txtExpReceiveDate" runat="server" Text='<%#Eval("exp_receive_date","{0:dd-MMM-yy}") %>' CssClass="DateControl" /> </td> </tr> </EditTemplate> </asp:ListView> <script type="text/javascript" language="javascript"> $(document).ready(function () { $('DateControl').datepick({ dateFormat: 'M-dd-yyyy' }); }); </script>

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  • (x86) Assembler Optimization

    - by Pindatjuh
    I'm building a compiler/assembler/linker in Java for the x86-32 (IA32) processor targeting Windows. High-level concepts of a "language" (in essential a Java API for creating executables) are translated into opcodes, which then are wrapped and outputted to a file. The translation process has several phases, one is the translation between languages: the highest-level code is translated into the medium-level code which is then translated into the lowest-level code (probably more than 3 levels). My problem is the following; if I have higher-level code (X and Y) translated to lower-level code (x, y, U and V), then an example of such a translation is, in pseudo-code: x + U(f) // generated by X + V(f) + y // generated by Y (An easy example) where V is the opposite of U (compare with a stack push as U and a pop as V). This needs to be 'optimized' into: x + y (essentially removing the "useless" code) My idea was to use regular expressions. For the above case, it'll be a regular expression looking like this: x:(U(x)+V(x)):null, meaning for all x find U(x) followed by V(x) and replace by null. Imagine more complex regular expressions, for more complex optimizations. This should work on all levels. What do you suggest? What would be a good approach to optimize in these situations?

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  • How to restrict text search to a certain subset of the database ?

    - by Nikhil Garg
    I have a large central database of around 1 million heavy records. In my app, for every user I would have a subset of rows from central table, which would be very small (probably 100 records each).When a particular user has logged in , I would want to search on this data set only. Example: Say I have a central database of all cars in the world. I have a user profile for General Motors(GM) , Ferrari etc. When GM is logged in I just want to search(a full text search and not fire a sql query) for those cars which are manufactured by GM. Also GM may launch/withdraw a model in which case central db would be updated & so would be rowset associated with GM. In case of acquisitions, db of certain profiles may change without launch/removal of new car. So central db wont change then , but rowsets may. Whats the best way to implement such a design ? These smaller row sets would need to be dynamic depending on user activities. We are on Rails 2.3.5 and use thinking_sphinx as the connector and Sphinx/MySQL for search and relational associations.

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  • copy rows before updating them to preserve archive in Postgres

    - by punkish
    I am experimenting with creating a table that keeps a version of every row. The idea is to be able to query for how the rows were at any point in time even if the query has JOINs. Consider a system where the primary resource is books, that is, books are queried for, and author info comes along for the ride CREATE TABLE authors ( author_id INTEGER NOT NULL, version INTEGER NOT NULL CHECK (version > 0), author_name TEXT, is_active BOOLEAN DEFAULT '1', modified_on TIMESTAMP DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (author_id, version) ) INSERT INTO authors (author_id, version, author_name) VALUES (1, 1, 'John'), (2, 1, 'Jack'), (3, 1, 'Ernest'); I would like to be able to update the above like so UPDATE authors SET author_name = 'Jack K' WHERE author_id = 1; and end up with 2, 1, Jack, t, 2012-03-29 21:35:00 2, 2, Jack K, t, 2012-03-29 21:37:40 which I can then query with SELECT author_name, modified_on FROM authors WHERE author_id = 2 AND modified_on < '2012-03-29 21:37:00' ORDER BY version DESC LIMIT 1; to get 2, 1, Jack, t, 2012-03-29 21:35:00 Something like the following doesn't really work CREATE OR REPLACE FUNCTION archive_authors() RETURNS TRIGGER AS $archive_author$ BEGIN IF (TG_OP = 'UPDATE') THEN -- The following fails because author_id,version PK already exists INSERT INTO authors (author_id, version, author_name) VALUES (OLD.author_id, OLD.version, OLD.author_name); UPDATE authors SET version = OLD.version + 1 WHERE author_id = OLD.author_id AND version = OLD.version; RETURN NEW; END IF; RETURN NULL; -- result is ignored since this is an AFTER trigger END; $archive_author$ LANGUAGE plpgsql; CREATE TRIGGER archive_author AFTER UPDATE OR DELETE ON authors FOR EACH ROW EXECUTE PROCEDURE archive_authors(); How can I achieve the above? Or, is there a better way to accomplish this? Ideally, I would prefer to not create a shadow table to store the archived rows.

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  • Is my method for avoiding dynamic_cast<> faster than dynamic_cast<> itself ?

    - by ereOn
    Hi, I was answering a question a few minutes ago and it raised to me another one: In one of my projects, I do some network message parsing. The messages are in the form of: [1 byte message type][2 bytes payload length][x bytes payload] The format and content of the payload are determined by the message type. I have a class hierarchy, based on a common class Message. To instanciate my messages, i have a static parsing method which gives back a Message* depending on the message type byte. Something like: Message* parse(const char* frame) { // This is sample code, in real life I obviously check that the buffer // is not NULL, and the size, and so on. switch(frame[0]) { case 0x01: return new FooMessage(); case 0x02: return new BarMessage(); } // Throw an exception here because the mesage type is unknown. } I sometimes need to access the methods of the subclasses. Since my network message handling must be fast, I decived to avoid dynamic_cast<> and I added a method to the base Message class that gives back the message type. Depending on this return value, I use a static_cast<> to the right child type instead. I did this mainly because I was told once that dynamic_cast<> was slow. However, I don't know exactly what it really does and how slow it is, thus, my method might be as just as slow (or slower) but far more complicated. What do you guys think of this design ? Is it common ? Is it really faster than using dynamic_cast<> ? Any detailed explanation of what happen under the hood when one use dynamic_cast<> is welcome !

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  • Error in Postgres execute

    - by RAJA
    I'm using this function... -- Function: dbo.sp_acc_createaccount(character varying, integer, integer, character varying, character varying, character varying, character varying) -- DROP FUNCTION dbo.sp_acc_createaccount(character varying, integer, integer, character varying, character varying, character varying, character varying); CREATE OR REPLACE FUNCTION dbo.sp_acc_createaccount(IN in_orgmgrtype character varying, INOUT in_parentid integer, IN in_levelid integer, IN in_name character varying, IN in_phone character varying, IN in_webpage character varying, IN in_owner character varying, OUT out_accountid integer) RETURNS record AS $BODY$ DECLARE l_CoID int; l_CurrID int; l_OrgMgrId int; errmsg varchar(250); BEGIN IF in_ParentID = -1 THEN errmsg := 'execute sp_Acc_GetCompanyIDForUser failed'; l_CoID := dbo.sp_Acc_GetCompanyIDForUser(in_user); IF l_CoID = -2 THEN RAISE EXCEPTION 'execute sp_Acc_GetCompanyIDForUser failed'; END IF; errmsg := 'execute sp_Acc_GetOrgMgrIDForCompany failed'; l_OrgMgrID := dbo.sp_Acc_GetOrgMgrIDForCompany(in_OrgMgrType, l_CoID); IF l_OrgMgrID = -2 THEN RAISE EXCEPTION 'execute sp_Acc_GetOrgMgrIDForCompany failed'; END IF; in_ParentID := l_OrgMgrID; ELSE errmsg := 'Select orgmgrid failed'; SELECT OrgMgrID INTO l_CurrID FROM dbo.OrgMgr WHERE Name = in_Name AND ParentID = in_ParentID; END IF; -- if not, add it IF l_CurrID IS NULL THEN errmsg := 'Insert into orgmgr(account creation) failed'; INSERT INTO dbo.OrgMgr (ParentID, LevelID, Name, PrimaryPhone, WebPage, Owner) VALUES (in_ParentID, in_LevelID, in_Name, in_Phone, in_WebPage, in_Owner); out_AccountID := currval('dbo.OrgMgr_accountid_seq'); ELSE out_AccountID := -1; END IF; COMMIT; EXCEPTION WHEN RAISE_EXCEPTION THEN out_AccountID := 99; RAISE NOTICE 'ERROR : %',errmsg; WHEN OTHERS THEN out_AccountID := 99; RAISE EXCEPTION 'ERROR : %',errmsg; END $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 100; ALTER FUNCTION dbo.sp_acc_createaccount(character varying, integer, integer, character varying, character varying, character varying, character varying) OWNER TO postgres; But.. it's showing error in execute time .. ERROR: SPI_execute_plan failed executing query "ROLLBACK": SPI_ERROR_TRANSACTION

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  • Is there a modern free D?VCS that can ignore mainframe sequence numbers?

    - by Brent.Longborough
    I'm looking at migrating a large suite of IBM Assembler Language programs, from a vcs based on "filenames include version numbers", to a modern vcs which will give me, among other things, the ability to branch and merge. These files have 80-column records, the last 8 columns being an almost-meaningless sequence number. For a number of reasons which I don't really want to waste space by going into, I need the vcs to ignore (but hopefully preserve in some well-defined manner) the sequence number columns, and to diff and patch based only on the contents of the first 72 columns. Any ideas? Just to clarify "ignore but preserve": I accept it's a bit vague, as I haven't fully collected my ideas yet. It would be something along the lines of this: "When merging/patching, if one side has sequence numbers, output them; if more-than-one side has sequence numbers, use those present in file (1|2|3)" Why do I want to preserve sequence numbers? First, they really are sequence numbers. Second, I want to reintegrate this stuff back onto the mainframe, where sequence numbers can be terribly significant. (Those of you who know what "SMP/E" means will understand. Those who don't, be happy, but tremble...) I've just realised I hadn't accepted an answer. Difficult choice, but @Noldorin comes closest to where I have to go.

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  • How is a referencing environment generally implemented for closures?

    - by Alexandr Kurilin
    Let's say I have a statically/lexically scoped language with deep binding and I create a closure. The closure will consist of the statements I want executed plus the so called referencing environment, or, to quote this post, the collection of variables which can be used. What does this referencing environment actually look like implementation-wise? I was recently reading about ObjectiveC's implementation of blocks, and the author suggests that behind the scenes you get a copy of all of the variables on the stack and also of all the references to heap objects. The explanation claims that you get a "snapshot" of the referencing environment at the point in time of the closure's creation. Is that more or less what happens, or did I misread that? Is anything done to "freeze" a separate copy of the heap objects, or is it safe to assume that if they get modified between closure creation and the closure executing, the closure will no longer be operating on the original version of the object? If indeed there's copying being made, are there memory usage considerations in situations where one might want to create plenty of closures and store them somewhere? I think that misunderstanding of some of these concepts might lead to tricky issues like the ones Eric Lippert mentions in this blog post. It's interesting because you'd think that it wouldn't make sense to keep a reference to a value type that might be gone by the time the closure is called, but I'm guessing that in C# the compiler will figure out that the variable is needed later and put it into the heap instead. It seems that in most memory-managed languages everything is a reference and thus ObjectiveC is a somewhat unique situation with having to deal with copying what's on the stack.

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  • Can you overlay transparent images in Blackberry Apps?

    - by Greg
    I have a very simple application that has one screen and one button. The main screen has a verticalFieldManager with a BitmapField inside it, and one button beneath the bitmap. I want to be able to overlay another image on top of this when the user clicks a button. The overlay image is a PNG with transparent background, and this is important for design, so I can't use popupscreen or a new screen because the backgrounds are always white by default, and I've heard alpha doesn't really do the trick. I guess what I'm asking is if anyone knows a simple way to... A) take a standard verticalFieldManager and overlay a PNG on top of the inner contents B) overlay a PNG over the screen, no matter the contents The basic functionality of this app was intended to be - show an image. on click, show another overlaid on top. on click again, remove the popup image. I haven't found anything that addresses something like this online, but I have read of people doing similar things that utilize popupscreen and new screens in a way I don't need to do. Hopefully this makes sense. Thanks

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