Search Results

Search found 23667 results on 947 pages for 'level design'.

Page 448/947 | < Previous Page | 444 445 446 447 448 449 450 451 452 453 454 455  | Next Page >

• Limit the number of service calls in a RESTful application

  - by Slavo

  Imagine some kind of a banking application, with a screen to create accounts. Each Account has a Currency and a Bank as a property, Currency being a separate class, as well as Bank. The code might look something like this: public class Account { public Currency Currency { get; set; } public Bank Bank { get; set; } } public class Currency { public string Code { get; set; } public string Name { get; set; } } public class Bank { public string Name { get; set; } public string Country { get; set; } } According to the REST design principles, each resource in the application should have its own service, and each service should have methods that map nicely to the HTTP verbs. So in our case, we have an AccountService, CurrencyService and BankService. In the screen for creating an account, we have some UI to select the bank from a list of banks, and to select a currency from a list of currencies. Imagine it is a web application, and those lists are dropdowns. This means that one dropdown is populated from the CurrencyService and one from the BankService. What this means is that when we open the screen for creating an account, we need to make two service calls to two different services. If that screen is not by itself on a page, there might be more service calls from the same page, impacting the performance. Is this normal in such an application? If not, how can it be avoided? How can the design be modified without going away from REST?

  Read the article

• How can I modify/merge Jinja2 dictionaries?

  - by Brian M. Hunt

  I have a Jinja2 dictionary and I want a single expression that modifies it - either by changing its content, or merging with another dictionary. >>> import jinja2 >>> e = jinja2.Environment() Modify a dict: Fails. >>> e.from_string("{{ x[4]=5 }}").render({'x':{1:2,2:3}}) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "jinja2/environment.py", line 743, in from_string return cls.from_code(self, self.compile(source), globals, None) File "jinja2/environment.py", line 469, in compile self.handle_exception(exc_info, source_hint=source) File "<unknown>", line 1, in template jinja2.exceptions.TemplateSyntaxError: expected token 'end of print statement', got '=' Two-stage update: Prints superfluous "None". >>> e.from_string("{{ x.update({4:5}) }} {{ x }}").render({'x':{1:2,2:3}}) u'None {1: 2, 2: 3, 4: 5}' >>> e.from_string("{{ dict(x.items()+ {3:4}.items()) }}").render({'x':{1:2,2:3}}) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "jinja2/environment.py", line 868, in render return self.environment.handle_exception(exc_info, True) File "<template>", line 1, in top-level template code TypeError: <lambda>() takes exactly 0 arguments (1 given) Use dict(x,**y): Fails. >>> e.from_string("{{ dict((3,4), **x) }}").render({'x':{1:2,2:3}}) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "jinja2/environment.py", line 868, in render return self.environment.handle_exception(exc_info, True) File "<template>", line 1, in top-level template code TypeError: call() keywords must be strings So how does one modify the dictionary x in Jinja2 by changing an attribute or merging with another dictionary? This question is similar to: How can I merge two Python dictionaries as a single expression? -- insofar as Jinja2 and Python are analogous.

  Read the article

• Maintaining a Python web application: heavier vs lighter framework?

  - by Tiberiu Ana

  Five+ years from now, you are hired to support and extend a data-centric web application written in Python that hasn't been kept up to date. Would you rather prefer it was written in the current version of Django/Pylons at the time, using the available standard components, or kept minimal with something like CherryPy/web.py and a few library dependencies? Heavy framework Advantages: standard approach to application design and structure, as encouraged by framework; less application code to worry about. Disadvantages: requires learning the framework to understand how things work; broken things in old version of framework difficult to fix; upgrading to new version potentially difficult due to changing APIs; finding relevant documentation/help potentially difficult due to changing APIs. Light framework Advantages: most application code is directly "visible"; only needed features are implemented; architecture should be simpler to understand; less need to upgrade external dependencies; easier to upgrade external dependencies. Disadvantages: some reinventing the wheel; non-standard design and structure (with the associated unique issues and bugs). I will update the list with any helpful answers.

  Read the article

• Auto switching databases from a rails app gracefully from the ApplicationController?

  - by Zaqintosh

  I've seen this post a few times, but haven't really found the answer to this specific question. I'd like to run a rails application that based on the detected request.host (imagine I have two subdomains points to the same rails app and server ip address: myapp1.domain.com and myapp2.domain.com). I'm trying to have myapp1 use the default "production" database, and myapp2 requests always use the alternative remote database. Here is an example of what I tried to do in Application controller that did not work: class ApplicationController < ActionController::Base helper :all before_filter :use_alternate_db private def use_alternate_db if request.host == 'myapp1.domain.com' regular_db elsif request.host == 'myapp2.domain.com' alternate_db end end def regular_db ActiveRecord::Base.establish_connection :production end def alternate_db ActiveRecord::Base.establish_connection( :adapter => 'mysql', :host => '...', :username => '...', :password => '...', :database => 'alternatedb' ) end end The problem is when it switches databases using this method, all connections (including valid sessions across the different subdomains get interrupted...). All examples online have people controlling database connectivity at the model level, but this would involve adding code all over my application. Is there some way to globally switch database connections on a per-request basis in the manner I'm suggesting above WITHOUT having to inject code all over my application? The added complexity here is I'm using Heroku as a hosting provider, so I have no control at the apache / rails application server level. I have looked at solutions like dbcharmer and magicmodels, but none seem to show examples of doing it in the manner that I'm trying to. Thanks for any help!

  Read the article

• what is the best way to stream a audio file to website users/listners

  - by Naveen Chamikara Gamage

  I'm developing a music site which will stream audio files stored in a server to users, audio files will be played through flash player placed in a webpage.. As I heard I need to use a streaming media server for streaming audio files ( like 2mb to 3mb in size).. Do I need to use one? I found some streaming media server softwares like http://www.icecast.org - but as in their documentation, It is used for streaming radio stations and live streaming purposes, but I just need to stream audio files faster and in low size (low bandwidth) with good quality.. I heard I need to encode the audio files first and then send them to listeners and in their end audio files need to be decoded again. Is that true? How can I do that? if I need to use a special web server, where should I host my files? Any good hosting providers? if I host audio files in a normal web server, they will use HTTP or TCP to deliver my audio files to users/ listners but I found that HTTP and TCP are not good ways to use for multi media purposes like streaming audio and video files, and they are used for delivering HTML and stuff. I found I should use RSTP or UDP for streaming audio files.. What should I use? I know that .MP3 files has much better quality than the other formats but it also gives huge size to the audio files.. which format should I use for audio files? Most of the best quality audio files are more than 7mb so I'm planning to convert them my self using a software so I could get low size files with some level of good quality. If I'm converting my audio files what is the good BITRATE I should use for my files? Any known best softwares for converting audio files while keeping quality in a good level? Note** - I know that I will not need complex requirements at the beginning of the site but I wanted to what are the best ways like they are using for soundcloud.com

  Read the article

• Using the MVVM Light Toolkit to make Blendable applications

  - by Dave

  A while ago, I posted a question regarding switching between a Blend-authored GUI and a Visual Studio-authored one. I got it to work okay by adding my Blend project to my VS2008 project and then changing the Startup Application and recompiling. This would result in two applications that had completely different GUIs, yet used the exact same ViewModel and Model code. I was pretty happy with that. Now that I've learned about the Laurent Bugnion's MVVM Light Toolkit, I would really like to leverage his efforts to make this process of supporting multiple GUIs for the same backend code possible. The question is, does the toolkit facilate this, or am I stuck doing it my previous way? I've watched his video from MIX10 and have read some of the articles about it online. However, I've yet to see something that indicates that there is a clean way to allow a user to either dynamically switch GUIs on the fly by loading a different DLL. There are MVVM templates for VS2008 and Blend 3, but am I supposed to create both types of projects for my application and then reference specific files from my VS2008 solution? UPDATE I re-read some information on Laurent's site, and seemed to have forgotten that the whole point of the template was to allow the same solution to be opened in VS2008 and Blend. So anyhow, with this new perspective it looks like the templates are actually intended to use a single GUI, most likely designed entirely in Blend (with the convenience of debugging through VS2008), and then be able to use two different ViewModels -- one for design-time, and one for runtime. So it seems to me like the answer to my question is that I want to use a combination of my previous solution, along with the MVVM Light Toolkit. The former will allow me to make multiple, distinct GUIs around my core code, while the latter will make designing fancy GUIs in Blend easier with the usage of a design-time ViewModel. Can anyone comment on this?

  Read the article

• How to make a GRANT persist for a table that's being dropped and re-created?

  - by Eli Courtwright

  I'm on a fairly new project where we're still modifying the design of our Oracle 11g database tables. As such, we drop and re-create our tables fairly often to make sure that our table creation scripts work as expected whenever we make a change. Our database consists of 2 schemas. One schema has some tables with INSERT triggers which cause the data to sometimes be copied into tables in our second schema. This requires us to log into the database with an admin account such as sysdba and GRANT access to the first schema to the necessary tables on the second schema, e.g. GRANT ALL ON schema_two.SomeTable TO schema_one; Our problem is that every time we make a change to our database design and want to drop and re-create our database tables, the access we GRANT-ed to schema_one went away when the table was dropped. Thus, this creates another annoying step wherein we must log in with an admin account to re-GRANT the access every time one of these tables is dropped and re-created. This isn't a huge deal, but I'd love to eliminate as many steps as possible from our development and testing procedures. Is there any way to GRANT access to a table in such a way that the GRANT-ed permissions survive a table being dropped and then re-created? And if this isn't possible, then is there a better way to go about this?

  Read the article

• Scaling Literate Programming?

  - by Tetha

  Greetings. I have been looking at Literate Programming a bit now, and I do like the idea behind it: you basically write a little paper about your code and write down as much of the design decisions, the code probably surrounding the module, the inner workins of the module, assumptions and conclusions resulting from the design decisions, potential extension, all this can be written down in a nice way using tex. Granted, the first point: it is documentation. It must be kept up-to-date, but that should not be that bad, because your change should have a justification and you can write that down. However, how does Literate Programming Scale to a larger degree? Overall, Literate Programming is still just text. Very human readable text, of course, but still text, and thus, it is hard to follow large systems. For example, I reworked large parts of my compiler to use and some magic to chain compile steps together, because some "x.register_follower(y); y.register_follower(z); y.register_follower(a);..." got really unwieldy, and changing that to x y z a made it a bit better, even though this is at its breaking point, too. So, how does Literate Programming scale to larger systems? Does anyone try to do that? My thought would be to use LP to specify components that communicate with each other using event streams and chain all of these together using a subset of graphviz. This would be a fairly natural extension to LP, as you can extract a documentation -- a dataflow diagram -- from the net and also generate code from it really well. What do you think of it? -- Tetha.

  Read the article

• log4net - how do I set DEBUG for my Console output, and INFO for my FileAppender?

  - by Greg

  Hi, I haven't quite worked this one out yet - how do I set DEBUG for my Console output, and INFO for my FileAppender? That is, how would I change the configuration below so that I can get the ConsoleAppender pumping out all logging from DEBUG upwards? Note that both appenders need to cover all logging (i.e. I don't want to use a scoped logger element that changes the log level for just one logger name) <log4net> <root> <level value="INFO" /> <appender-ref ref="LogFileAppender" /> <appender-ref ref="ConsoleAppender" /> </root> <appender name="LogFileAppender" type="log4net.Appender.FileAppender" > <param name="File" value="log-file.txt" /> <param name="AppendToFile" value="true" /> <layout type="log4net.Layout.PatternLayout"> <param name="Header" value="[Header]\r\n"/> <param name="Footer" value="[Footer]\r\n"/> <param name="ConversionPattern" value="%d [%t] %-5p %c [%x] - %m%n" /> </layout> <filter type="log4net.Filter.LevelRangeFilter"> <param name="LevelMin" value="DEBUG" /> <param name="LevelMax" value="WARN" /> </filter> </appender> <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender" > <layout type="log4net.Layout.PatternLayout"> <param name="ConversionPattern" value="%d [%t] %-5p %c [%x] - %m%n" /> </layout> </appender> </log4net>

  Read the article

• Managing common components with Fossil CVS

  - by Larry Lustig

  I'm a Fossil (and CVS configuration novice) attempting to create and manage a set of distributed Fossil repositories for a Delphi project. I have the following directory tree: Projects Some Project Delphi Components LookupListView Some Client Some Project For Client Some Other Project For Client Source Code Project Resources Project Database I am setting up Fossil version control in order to version and share Projects\Some Client\Some Other Project For Client\Source Code, which contains Delphi 2010 source for a database project. This project makes use of Projects\Delphi Components\LookupListView which is a Delphi component. I need this code to be included in the versioning system for my project. I will, in theory, need to include it in other Fossil repositories in the future, as well. If I create my Fossil repository at the Source Code or Some Other Project For Client level, I cannot add any code above that level to my repository. What is the proper way to deal with this? The two solutions that occur to me are 1) Creating a separate repository for LookupListView and make sure that everyone who uses a repository for a project that references it "knows" that they must also get the current version of this project as well. This seems to defeat the purpose of being able to obtain a complete, current version of the project with a single checkout. The problem is magnified because there are other common component dependencies in this project. 2) Establishing my Fossil repository in the Projects directory, so I can check in files from various subfolders. This seems to me to involve an awful lot of extra path-typing when doing adds, and also to impose my directory structure (Some Client\Some Other Project For Client\Source) on the other users of the repository -- in this case, the actual client. Any suggestions appreciated.

  Read the article

• How to effectively use WorkbookBeforeClose event correctly?

  - by Ahmad

  On a daily basis, a person needs to check that specific workbooks have been correctly updated with Bloomberg and Reuters market data ie. all data has pulled through and that the 'numbers look correct'. In the past, people were not checking the 'numbers' which led to inaccurate uploads to other systems etc. The idea is that 'something' needs to be developed to prevent the use from closing/saving the workbook unless he/she has checked that the updates are correct/accurate. The numbers look correct action is purely an intuitive exercise, thus will not be coded in any way. The simple solution was to prompt users prior to closing the specific workbook to verify that the data has been checked. Using VSTO SE for Excel 2007, an Add-in was created which hooks into the WorkbookBeforeClose event which is initialised in the add-in ThisAddIn_Startup private void wb_BeforeClose(Xl.Workbook wb, ref bool cancel) { //.... snip ... if (list.Contains(wb.Name)) { DailogResult result = MessageBox.Show("some message", "sometitle", MessageBoxButtons.YesNo); if (result != DialogResult.Yes) { cancel = true; // i think this prevents the whole application from closing } } } I have found the following ThisApplication.WorkbookBeforeSave vs ThisWorkbook.Application.WorkbookBeforeSave which recommends that one should use the ThisApplication.WorkbookBeforeClose event which I think is what I am doing since will span all files opened. The issue I have with the approach is that assuming that I have several files open, some of which are in my list, the event prevents Excel from closing all files sequentially. It now requires each file to be closed individually. Am I using the event correctly and is this effective & efficient use of the event? Should I use the Application level event or document level event? Is there a way to prevent the above behaviour? Any other suggestions are welcomed VS 2005 with VSTO SE

  Read the article

• ASP Classic, SQL 2008, XML Output, and DSN vs DSN-Less Produces Chinese Letters

  - by RoLYroLLs

  I've been having a problem for the past month and can't seem to figure out what is wrong. Here's the setup and a little background. Background: I have a web-host who was running my website on Windows Server 2003 and SQL Server 2000. One of my webpages returned a result set from a stored procedure from the SQL server as xml. Below is the code: Stored Procedure: select top 10 1 as tag , null as parent , column1 as [item!1!column1!element] , column2 as [item!1!column2!element] from table1 for XML EXPLICIT ASP Page: index.asp Call OpenConn Set cmd = Server.CreateObject("ADODB.Command") With cmd .ActiveConnection = dbc .CommandText = "name of proc" .CommandType = adCmdStoredProc .Parameters.Append .CreateParameter("@RetVal", adInteger, adParamReturnValue, 4) .Parameters.Append .CreateParameter("@Level", adInteger, adParamInput, 4, Level) End With Set rsItems = Server.CreateObject("ADODB.Recordset") With rsItems .CursorLocation = adUseClient .CursorType = adOpenStatic .LockType = adLockBatchOptimistic Set .Source = cmd .Open Set .ActiveConnection = Nothing End With If NOT rsItems.BOF AND NOT rsItems.EOF Then OutputXMLQueryResults rsItems,"items" End If Set rsItems = Nothing Set cmd = Nothing Call CloseConn Sub OpenConn() strConn = "Provider=SQLOLEDB;Data Source=[hidden];User Id=[hidden];Password=[hidden];Initial Catalog=[hidden];" Set dbc = Server.CreateObject("ADODB.Connection") dbc.open strConn End Sub Sub CloseConn() If IsObject(dbc) Then If dbc.State = adStateOpen Then dbc.Close End If Set dbc = Nothing End If End Sub Sub OutputXMLQueryResults(RS,RootElementName) Response.Clear Response.ContentType = "text/xml" Response.Codepage = 65001 Response.Charset = "utf-8" Response.Write "" Response.Write "" While Not RS.EOF Response.Write RS(0).Value RS.MoveNext WEnd Response.Write "" Response.End End Sub Present: All was working great, until my host upgraded to Windows Server 2008 and SQL Server 2008. All of the sudden I was getting results like this: From Browser: From View Source: However, I found that if I use a DSN connection strConn = "DSN=[my DSN Name];User Id=[hidden];Password=[hidden];Initial Catalog=[hidden];" it works perfectly fine! My current host is not going to support DSN any longer, but that's out of scope for this issue. Someone told me to use an ADO.Stream object instead of a Recordset object, but I'm unsure how to implement that. Question: Has anyone run into this and found a way to fix it? What about that ADO.Stream object, can someone help me with a sample that would fit my code?

  Read the article

• java.io.IOException: Premature EOF

  - by jouzef19

  Hi: I am trying to download an xml file using Stream and things was fine , until the xml size became bigger than 9 MB , so i've got this error java.io.IOException: Premature EOF this is the code BufferedInputStream bfi = null; try { bfi = new BufferedInputStream(new URL("The URL").openStream()); String name = "name.xml"; FileOutputStream fb = new FileOutputStream(name); BufferedOutputStream bout = new BufferedOutputStream(fb, 1024); byte[] data = new byte[1024]; int x = 0; while ((x = bfi.read(data, 0, 1024)) >= 0) { bout.write(data, 0, x); } this.deletePhishTankDatabase(this.recreateFileName()); ptda.insertDownloadTime(hour, day, month, year); bout.close(); bfi.close(); } catch (IOException ex) { Logger.getLogger(PhishTankDataBase.class.getName()).log(Level.SEVERE, null, ex); } finally { try { bfi.close(); } catch (IOException ex) { Logger.getLogger(PhishTankDataBase.class.getName()).log(Level.SEVERE, null, ex); } } } else { System.out.println("You can't do anything"); return; } thanks in advanced

  Read the article

• Create Keyword Object Perl Microsoft::AdCenter

  - by toobsco42

  So I looked at the perldoc for the Microsoft::AdCenter module and it shows this as an example of how to create a keyword object: ~$ perldoc Microsoft::AdCenter #Create a Keyword object my $keyword = Microsoft::AdCenter::V7::CampaignManagementService::Keyword->new ->Text("some text") ->BroadMatchBid(Microsoft::AdCenter::V7::CampaignManagementService::Bid->new->Amount(0.1)) ->ExactMatchBid(Microsoft::AdCenter::V7::CampaignManagementService::Bid->new->Amount(0.1)); However, doesn't this violate the new policy of using only one match type per keyword? Campaign Management changes: "Previously, you would create a single Keyword object and specify a bid value for each match that you wanted to bid on (for example, exact match or phrase match). If you did not specify a bid value at the keyword-level, adCenter used the default bid value specified at the ad group level. Now, you must create a Keyword object for each match type that you want to bid on. For example, to bid on the keyword car by using exact match and phrase match, create a Keyword object and set the Text element to car and the ExactMatchBid element to a bid amount. Then, create a second Keyword object and set the Text element to car and PhraseMatchBid to a bid amount. When you add the keywords, you’ll get a unique keyword ID for each keyword and match-type combination."

  Read the article

• Checkstyle: cannot summarise issues per author ?

  - by David Michel

  Hi all, I'm trying to use checkstyle for a java project but I can't seem to get it working properly: While it apparently runs smoothly, the html report doesn't give any info per authors as it should, i.e. the authors table is empty. The thing is I don't know how checkstyle identify an author. Does it look at the java doc tag @author ? at the class level or at the method level ? The ant task I used is below: <taskdef resource="checkstyletask.properties" classpath="${libs.dir}/checkstyle-all-5.0.jar"/> <target name="checkstyle" description="Generates a report of code convention violations."> <mkdir dir="${checkstyle.dir}"/> <checkstyle config="${util.dir}/checkstyle/sun_checks.xml" failureProperty="checkstyle.failure" failOnViolation="false"> <formatter type="xml" tofile="${checkstyle.dir}/checkstyle_report.xml"/> <fileset dir="${src.dir}" includes="**/*.java"/> </checkstyle> <xslt in="${checkstyle.dir}/checkstyle_report.xml" out="${checkstyle.dir}/checkstyle_report.html" style="${util.dir}/checkstyle/checkstyle-author.xsl"/> </target> Many thanks for your help David

  Read the article

• How to handle missing files on MVC

  - by kaivalya

  What is your preferred way to handle hits to files that does not exist on your MVC app. I have couple of web apps runing with MVC and they are constantly getting hits for files folders etc. that does not exist in the app structure. Apps are throwing exception: The controller for path could not be found or it does not implement IController I am trying to find out the best way to handle this. I have 3 global routes on my global.asax file (see below) and at this point I am happy with that simple definition. I know if I added route definition for all controllers then I can add a definition to ignore the rest and handle these hits but if it will be possible to solve this problem without it, I do not want to add route definitions for each controller which I believe will flood the route definitions and also add a layer of maintenance which I don't like. //Aggregates 2nd level routes.MapRoute( "AggregateLevel2", "{controller}/{action}/{id}/{childid}/{childidlevel2}", new { controller = "Home", action = "Index", id = "", childid = "", childidlevel2 = "" } ); //Aggregates 1st level routes.MapRoute( "AggregateLevel1", "{controller}/{action}/{id}/{childid}", new { controller = "Home", action = "Index", id = "", childid = "" } ); routes.MapRoute( "Default", "{controller}/{action}/{id}", new { controller = "Home", action = "Index", id = "" } );

  Read the article

• GWT Html Layout Conventions

  - by brad

  I've just started working with GWT and I'm already recognizing the extraordinary power that it possesses. I'm coming from a frontend world so the Java is a big learning curve, but I think that will actually help me build a properly laid out app (html-wise) instead of just relying on the default GWT panels that often end up using tables for layout, or superfluous, absolutely positioned divs. The biggest thing slowing me down right now however is deciding how to properly lay out the design of my site. I've got a pretty standard 2-col header/foot site (fixed width) that I want to design, but I'm not a fan of all the extra divs/styling etc that come with the DockLayoutPanel for instance. I'm thinking that I should just write my own Layout widget extending Composite that has HTMLPanels for the general site layout (I think... still haven't fully figured that out yet, ie. how do I add ID's to these panel divs "#header", "#nav" etc...) then I can add other widgets into this layout But the other thing I'm seeing is that I could write a Layout class extending UiBuilder and have straight up divs in the ui.xml file. I'm just wondering, what is the preferred method for site layout with GWT? This isn't going to be re-used in the sense of other widgets, it will be used once and my controls etc will be placed inside. Any tips or tricks are greatly appreciated! And if I've completely missed the boat on how to do this, let me know

  Read the article

• MySQL return Deadlock with insert row and FK is locked 'for update'

  - by constantin-slednev

  Hello developers! I get deadlock error in my mysql transaction. The simple example of my situation: Thread1 > set autocommit=0; Query OK, 0 rows affected (0.00 sec) Thread1 > SET TRANSACTION ISOLATION LEVEL READ COMMITTED; Query OK, 0 rows affected (0.00 sec) Thread1 > SELECT * FROM A WHERE ID=1000 FOR UPDATE; 1 row in set (0.00 sec) Thread2 > set autocommit=0; Query OK, 0 rows affected (0.00 sec) Thread2 > SET TRANSACTION ISOLATION LEVEL READ COMMITTED; Query OK, 0 rows affected (0.00 sec) Thread2 > INSERT INTO B (AID, NAME) VALUES (1000, 'Hello world'); SLEEP Query OK, 1 row affected (4.99 sec) Thread1 > INSERT INTO B (AID, NAME) VALUES (1000, 'Hello world2'); ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction B.AID -> FK -> A.ID I see three solutions: catch deadlock error in code and retry query. use innodb_locks_unsafe_for_binlog in my.cnf lock (for update) table A in Thread2 before insert Can you give me more solutions ? Current solutions do not fit me.

  Read the article

• What is the best practice for using lock within inherited classes

  - by JDMX

  I want to know if one class is inheriting from another, is it better to have the classes share a lock object that is defined at the base class or to have a lock object defined at each inheritance level. A very simple example of a lock object on each level of the class public class Foo { private object thisLock = new object(); private int ivalue; public int Value { get { lock( thisLock ) { return ivalue; } } set { lock( thisLock ) { ivalue= value; } } } } public class Foo2: Foo { private object thisLock2 = new object(); public int DoubleValue { get { lock( thisLock2 ) { return base.Value * 2; } } set { lock( thisLock2 ) { base.Value = value / 2; } } } } public class Foo6: Foo2 { private object thisLock6 = new object(); public int TripleDoubleValue { get { lock( thisLock6 ) { return base.DoubleValue * 3; } } set { lock( thisLock6 ) { base.DoubleValue = value / 3; } } } } A very simple example of a shared lock object public class Foo { protected object thisLock = new object(); private int ivalue; public int Value { get { lock( thisLock ) { return ivalue; } } set { lock( thisLock ) { ivalue= value; } } } } public class Foo2: Foo { public int DoubleValue { get { lock( thisLock ) { return base.Value * 2; } } set { lock( thisLock ) { base.Value = value / 2; } } } } public class Foo6: Foo2 { public int TripleDoubleValue { get { lock( thisLock ) { return base.DoubleValue * 3; } } set { lock( thisLock ) { base.DoubleValue = value / 3; } } } } Which example is the preferred way to manage locking within an inherited class?

  Read the article

• perl dynamic path given to 'use lib'

  - by Ed Hyer

  So, my code (Perl scripts and Perl modules) sits in a tree like this: trunk/ util/ process/ scripts/ The 'util' directory has, well, utilities, that things in the 'process/' dir need. They get access like this: use FindBin; use lib "$FindBin::Bin/../util"; use UtilityModule qw(all); That construct doesn't care where you start, as long as you're at the same level in the tree as "util/". But I decided that 'scripts/' was getting too crowded, so I created scripts/scripts1 scripts/scripts2 Now I see that this doesn't work. If I run a script 'trunk/scripts/scripts1/call_script.pl', and it calls '/trunk/process/process_script.pl', then 'process_script.pl' will fail trying to get the routines from UtilityModule(), because the path that FindBin returns is the path of the top-level calling script. The first ten ways I thought of to solve this all involved something like: use lib $path_that_came_from_elsewhere; but that seems to be something Perl doesn't like to do, except via that FindBin trick. I tried some things involving BEGIN{} blocks, but i don't really know what I'm doing there, and will likely just end up refactoring. But if someone has some clever insight into this type of problem, this would be a good chance to earn some points!

  Read the article

• Which technology is best suited to store and query a huge readonly graph?

  - by asmaier

  I have a huge directed graph: It consists of 1.6 million nodes and 30 million edges. I want the users to be able to find all the shortest connections (including incoming and outgoing edges) between two nodes of the graph (via a web interface). At the moment I have stored the graph in a PostgreSQL database. But that solution is not very efficient and elegant, I basically need to store all the edges of the graph twice (see my question PostgreSQL: How to optimize my database for storing and querying a huge graph). It was suggested to me to use a GraphDB like neo4j or AllegroGraph. However the free version of AllegroGraph is limited to 50 million nodes and also has a very high-level API (RDF), which seems too powerful and complex for my problem. Neo4j on the other hand has only a very low level API (and the python interface is not mature yet). Both of them seem to be more suited for problems, where nodes and edges are frequently added or removed to a graph. For a simple search on a graph, these GraphDBs seem to be too complex. One idea I had would be to "misuse" a search engine like Lucene for the job, since I'm basically only searching connections in a graph. Another idea would be, to have a server process, storing the whole graph (500MB to 1GB) in memory. The clients could then query the server process and could transverse the graph very quickly, since the graph is stored in memory. Is there an easy possibility to write such a server (preferably in Python) using some existing framework? Which technology would you use to store and query such a huge readonly graph?

  Read the article

• SQL Stored Queries - use result of query as boolean based on existence of records

  - by Christian Mann

  Just getting into SQL stored queries right now... anyway, here's my database schema (simplified for YOUR convenience): member ------ id INT PK board ------ id INT PK officer ------ id INT PK If you're into OOP, Officer Inherits Board Inherits Member. In other words, if someone is listed on the officer table, s/he is listed on the board table and the member table. I want to find out the highest privilege level someone has. So far my SP looks like this: DELIMITER // CREATE PROCEDURE GetAuthLevel(IN targetID MEDIUMINT) BEGIN IF SELECT `id` FROM `member` WHERE `id` = targetID; THEN IF SELECT `id` FROM `board` WHERE `id` = targetID; THEN IF SELECT `id` FROM `officer` WHERE `id` = targetID; THEN RETURN 3; /*officer*/ ELSE RETURN 2; /*board member*/ ELSE RETURN 1; /*general member*/ ELSE RETURN 0; /*not a member*/ END // DELIMITER ; The exact text of the error is #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT id FROM member WHERE id = targetID; THEN IF SEL' at line 4 I suspect the issue is in the arguments for the IF blocks. What I want to do is return true if the result-set is at least one -- i.e. the id was found in the table. Do any of you guys see anything to do here, or should I reconsider my database design into this:? person ------ id INT PK level SMALLINT

  Read the article

• NHibernate + Remoting = ReflectionPermission Exception

  - by Pedro

  Hi all, We are dealing with a problem when using NHibernate with Remoting in a machine with full trust enviroment (actually that's our dev machine). The problem happens when whe try to send as a parameter an object previously retrieved from the server, that contains a NHibernate Proxy in one of the properties (a lazy one). As we are in the dev machine, there's no restriction in the trust level of the web app (it's set to Full) and, as a plus, we've configured NHibernate's and Castle's assemblies to full trust in CAS (even thinking that it'd not be necessary as the remoting app in IIS has the full trust level). Does anyone have any idea of what can be causing this exception? Stack trace below. InnerException: System.Security.SecurityException Message="Falha na solicitação da permissão de tipo 'System.Security.Permissions.ReflectionPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'." Source="mscorlib" GrantedSet="" PermissionState="<IPermission class=\"System.Security.Permissions.ReflectionPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\"\r\nversion=\"1\"\r\nFlags=\"ReflectionEmit\"/>\r\n" RefusedSet="" Url="" StackTrace: em System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) em System.Security.CodeAccessPermission.Demand() em System.Reflection.Emit.AssemblyBuilder.DefineDynamicModuleInternalNoLock(String name, Boolean emitSymbolInfo, StackCrawlMark& stackMark) em System.Reflection.Emit.AssemblyBuilder.DefineDynamicModuleInternal(String name, Boolean emitSymbolInfo, StackCrawlMark& stackMark) em System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule(String name, Boolean emitSymbolInfo) em Castle.DynamicProxy.ModuleScope.CreateModule(Boolean signStrongName) em Castle.DynamicProxy.ModuleScope.ObtainDynamicModuleWithWeakName() em Castle.DynamicProxy.ModuleScope.ObtainDynamicModule(Boolean isStrongNamed) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter.CreateTypeBuilder(ModuleScope modulescope, String name, Type baseType, Type[] interfaces, TypeAttributes flags, Boolean forceUnsigned) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter..ctor(ModuleScope modulescope, String name, Type baseType, Type[] interfaces, TypeAttributes flags, Boolean forceUnsigned) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter..ctor(ModuleScope modulescope, String name, Type baseType, Type[] interfaces, TypeAttributes flags) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter..ctor(ModuleScope modulescope, String name, Type baseType, Type[] interfaces) em Castle.DynamicProxy.Generators.BaseProxyGenerator.BuildClassEmitter(String typeName, Type parentType, Type[] interfaces) em Castle.DynamicProxy.Generators.BaseProxyGenerator.BuildClassEmitter(String typeName, Type parentType, IList interfaceList) em Castle.DynamicProxy.Generators.ClassProxyGenerator.GenerateCode(Type[] interfaces, ProxyGenerationOptions options) em Castle.DynamicProxy.Serialization.ProxyObjectReference.RecreateClassProxy() em Castle.DynamicProxy.Serialization.ProxyObjectReference.RecreateProxy() em Castle.DynamicProxy.Serialization.ProxyObjectReference..ctor(SerializationInfo info, StreamingContext context) Thank you in advance.

  Read the article

• Exam Questions that use .Demand or .LinkDemand COULD NOT BE ANY MORE CONFUSING OR AMBIGIOUS ????

  - by IbrarMumtaz

  I am 110% sure this is WRONG !!!! Q.12) You develop a library, and want to ensure that the functions in the library cannot be either directly or indirectly invoked by applications that are not running on the local intranet. What attribute would you add to each method? A. [UrlIdentityPermission(SecurityAction.RequestRefuse, Url="http://myintranet")] B. [UrlIdentityPermission(SecurityAction.LinkDemand, Url="http://myintranet")] (correct answer) C. [UrlIdentityPermission(SecurityAction.Demand, Url="http://myintranet")] D. [UrlIdentityPermission(SecurityAction.Assert, Url="http://myintranet")] Explanation Link-Demand should be used as it ensures that all callers in the call stack have the necessary permission. In this case it ensures that all callers in the call stack are on the local intranet. There is an indentical question on Transencer so I already had a clue what was goin but Transcender was much more informative that this drivel as it mentioned class level and not assembly level. It also mentioned that some callers maybe coming externally from the company intranet via authroised and authenticated credentials. With information is easy to see why .Demand on would be wong option to go for? So Transcender was right .... so I thgt fine, that makes sense. With think information still fresh in my brain I had a good idea was was going on in the question. To my surprise .Demand was wrong agin !!!! WHAT? I am really starting to hate this setting now? I cannot be any more p*ssed right now!!! :@ Thanks For Reading, Ibrar

  Read the article

• Project Architecture For Enhancing Legacy project.

  - by vijay.shad

  I am working on legacy project. Now the situation demands project to be divided into parts. What strategy I should follow to do this task. Description: The legacy project (A) is fully functional web application with almost well defined layers. But now i need to extend the project to a further enhancement. This project usage maven as build tool. But it is used only for dependency managements only. (project exported to war form inside eclipse). The new enhancement needs me to add new data table, new UI(jsp, css, js and images). What should be my strategy to enhance to application. My proposed design. I am planing to create two new projects Project B : Main Enhancement works will done in this project. Will have all layers like service layer, dao layer and UI layer in itself. And will be a web application in itself. Project C : Extract some common model and service code form project-A and create this project. This project will be added as dependency to both the projects. If my this approach is okay! Then i presume there will be problem be problem in deployment. These two projects will demand to deploy separately(currently tomcat is used). But I must deploy these two projects as one war. So, i need to have a plan to change the web.xml entries to have configurations for both projects. This will comes with some more complexities with project. What should be my design for the project? Does my plan sounds good.

  Read the article

< Previous Page | 444 445 446 447 448 449 450 451 452 453 454 455  | Next Page >