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  • Winforms role based security limitations

    - by muhan
    I'm implementing role based security using Microsoft's membership and role provider. The theoretical problem I'm having is that you implement a specific role on a method such as: [PrincipalPermissionAttribute(SecurityAction.Demand, Role="Supervisor")] private void someMethod() {} What if at some point down the road, I don't want Supervisors to access someMethod() anymore? Wouldn't I have to change the source code to make that change? Am I missing something? It seems there has to be some way to abstract the relationship between the supervisors role and the method so I can create a way in the application to change this coupling of role permission to method. Any insight or direction would be appreciated. Thank you.

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  • Hibernate limitations on using variables in queries

    - by sammichy
    I had asked the following question I have the following table structure for a table Player Table Player { Long playerID; Long points; Long rank; } Assuming that the playerID and the points have valid values, can I update the rank for all the players based on the number of points in a single query? If two people have the same number of points, they should tie for the rank. And received the answer from Daniel Vassalo (thank you). UPDATE player JOIN (SELECT p.playerID, IF(@lastPoint <> p.points, @curRank := @curRank + 1, @curRank) AS rank, IF(@lastPoint = p.points, @curRank := @curRank + 1, @curRank), @lastPoint := p.points FROM player p JOIN (SELECT @curRank := 0, @lastPoint := 0) r ORDER BY p.points DESC ) ranks ON (ranks.playerID = player.playerID) SET player.rank = ranks.rank; When I try to execute this as a native query in Hibernate, the following exception is thrown. java.lang.IllegalArgumentException: org.hibernate.QueryException: Space is not allowed after parameter prefix ':' Apparently this has been an open issue for the last couple of years, I want to know if the ranking query can be made to work either Without using any variables in the SQL query OR Using any workaround for Hibernate.

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  • Practical size limitations for RDBMS

    - by grenade
    I am working on a project that must store very large datasets and associated reference data. I have never come across a project that required tables quite this large. I have proved that at least one development environment cannot cope at the database tier with the processing required by the complex queries against views that the application layer generates (views with multiple inner and outer joins, grouping, summing and averaging against tables with 90 million rows). The RDBMS that I have tested against is DB2 on AIX. The dev environment that failed was loaded with 1/20th of the volume that will be processed in production. I am assured that the production hardware is superior to the dev and staging hardware but I just don't believe that it will cope with the sheer volume of data and complexity of queries. Before the dev environment failed, it was taking in excess of 5 minutes to return a small dataset (several hundred rows) that was produced by a complex query (many joins, lots of grouping, summing and averaging) against the large tables. My gut feeling is that the db architecture must change so that the aggregations currently provided by the views are performed as part of an off-peak batch process. Now for my question. I am assured by people who claim to have experience of this sort of thing (which I do not) that my fears are unfounded. Are they? Can a modern RDBMS (SQL Server 2008, Oracle, DB2) cope with the volume and complexity I have described (given an appropriate amount of hardware) or are we in the realm of technologies like Google's BigTable? I'm hoping for answers from folks who have actually had to work with this sort of volume at a non-theoretical level.

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  • limitations of xpath to distinguish and locate web elements on page

    - by wefwgeweg
    are there any alternatives to Xpath ? need to locate and extract specific element's texts for web scraping project. xpath seem pretty limited against layout changes on web pages. slight shuffle, and xpath no longer works. also different browsers have different Xpaths as i discovered. Firefox automatically adds tbody after table, while IE doesn't and so on.

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  • archiving strategies and limitations of data in a table

    - by Samuel
    Environment: Jboss, Mysql, JPA, Hibernate Our web application will be catering to a large amount of users (~ 1,000,000) and there are a lots of child table where user specific data are stored (e.g. personal, health, forum contributions ...). What would be the best practice to archive user & user specific information. [a] Would it be wise to move the archived user & user specific information to their respective tables within the same database (e.g. user_archive, user_forum_comments_archive ...) OR [b] Would you just mark the database entries with a flag in the original table(s) and just query only non archived entries. We have a unique constraint on User.loginid, how do you handle this requirement if the users are archived via 1-[a] (i.e if a user with loginid 'samuel' gets moved into the archive table and if a new user gets added with the same name in the original table, how would you prevent this. What would be the best strategy to address the unique key constraints. We have a requirement to selectively archive records and bring it back if necessary, will you rely on database tools are would you handle this via your persistence APIs exposed by the JPA entity model.

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  • I am trying to build a list of limitations of all graph algorithms

    - by Jack
    Single Source shortest Path Dijkstra's - directed and undirected - works only for positive edge weights - cycles ?? Bellman Ford - directed - no cycles should exist All source shortest path Floyd Warshall - no info Minimum Spanning Tree ( no info about edge weights or nature of graph or cycles) Kruskal's Prim's - undirected Baruvka's

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  • Unusual heap size limitations in VS2003 C++

    - by Shane MacLaughlin
    I have a C++ app that uses large arrays of data, and have noticed while testing that it is running out of memory, while there is still plenty of memory available. I have reduced the code to a sample test case as follows; void MemTest() { size_t Size = 500*1024*1024; // 512mb if (Size > _HEAP_MAXREQ) TRACE("Invalid Size"); void * mem = malloc(Size); if (mem == NULL) TRACE("allocation failed"); } If I create a new MFC project, include this function, and run it from InitInstance, it works fine in debug mode (memory allocated as expected), yet fails in release mode (malloc returns NULL). Single stepping through release into the C run times, my function gets inlined I get the following // malloc.c void * __cdecl _malloc_base (size_t size) { void *res = _nh_malloc_base(size, _newmode); RTCCALLBACK(_RTC_Allocate_hook, (res, size, 0)); return res; } Calling _nh_malloc_base void * __cdecl _nh_malloc_base (size_t size, int nhFlag) { void * pvReturn; // validate size if (size > _HEAP_MAXREQ) return NULL; ' ' And (size _HEAP_MAXREQ) returns true and hence my memory doesn't get allocated. Putting a watch on size comes back with the exptected 512MB, which suggests the program is linking into a different run-time library with a much smaller _HEAP_MAXREQ. Grepping the VC++ folders for _HEAP_MAXREQ shows the expected 0xFFFFFFE0, so I can't figure out what is happening here. Anyone know of any CRT changes or versions that would cause this problem, or am I missing something way more obvious?

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  • Disk IO Performance Limitations based on numbers of folders/files

    - by Josh
    I have an application where users are allowed to upload images to the server. Our Web Server is a windows 2008 server and we have a site (images.mysite.com) that points to a shared drive on a unix box. The code used to do the uploading is C# 3.5. The system currently supports a workflow where after a threshold is met a new subfolder can be generated. The question we have is how many files and/or subfolders can you have in a single folder before there is a degredation in performance - in serving the images up through IIS 7 and reading/writing through code?

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  • What are the Limitations for Connecting to an Access Query in Excel

    - by thornomad
    I have an Access 2007 database that has a number of tables, some are fairly large (100,000+ records); I have created a union query to pull some of the same types of data from multiple tables into one large query for pivot table manipulation and reporting. For example: SELECT Language FROM Table1 UNION ALL SELECT Language FROM Table2 UNION ALL SELECT Language FROM Table3; This works. I found, quickly, however, that a union query will not show up when connecting to the datasource from Excel 2007. So, I created a second query to reference the union query. Like so: SELECT * FROM [The Above Union Query]; This query works and it, initially, was accessible from Excel. Time passed, I've added more data. Suddenly, when I connect to my Access database from Excel my query referencing the union has disappeared. MS Access shows no signs of an issue (data displays in Access) and my other non-union queries are showing up in Excel 2007 ... but not the one that references the union. What could be going on? Why did it disappear? I noticed if I switch some of the referenced tables in the union query to a smaller table (with less rows) all of sudden the query appears in Excel again. At least, I think that's what the difference is. I really can't put my finger on why some of the union queries won't show up and some will. Am stumped and need some guidance. Thanks.

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  • Where are tables in Mnesia located?

    - by Sanoj
    I try to compare Mnesia with more traditional databases. As I understand it tables in Mnesia can be located to: ram_copies - tables are stored in RAM only, so no durability as in ACID. disc_copies - tables are located on disc and a copy is located in RAM, so the table can not be bigger than the available memory? disc_only_copies - tables are located to disc only, so no caching in memory and worse performance? And the size of the table are limited to the size of dets or the table has to be fragmented. So if I want the performance of doing reads from RAM and the durability of writes to disc, then the size of the tables are very limited compared to a traditional RDBMS like MySQL or PostgreSQL. I know that Mnesia aren't meant to replace traditional RDBMS:s, but can it be used as a big RDBMS or do I have to look for another database? The server I will use is a VPS with limited amount of memory, around 512MB, but I want good database performance. Are disc_copies and the other types of tables in Mnesia so limited as I have understood?

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  • mysql: how to set max_allowed_packet for shared hosting?

    - by Sadi
    Hello, I need to set (increase) max_allowed_packet. But the problem is I am using a shared hosting. So, I can not access the .ini or .cnf file. Also I can not use the SET command. How can I am able to set a value (actually increase) for the max_allowed_packet, without asking the hosting support. I have no SSH access there. EDIT: I am trying to use VB 4.0.3. In there the attachment size is limited by it. So, I do not think splitting the file can be an option in this case. Thank you Sadi

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  • JSON limitation?

    - by thedp
    Hello, I would like to know if JSON with AJAX has a limitation to the amount of data an outgoing and returning parameter can carry? I would like to be able to send and return from the server a file with 10,000 lines, as a string. How should I achieve this task? Will a single parameter will be able to hand this? Thank you.

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  • Why no switch on pointers?

    - by meeselet
    For instance: #include <stdio.h> void why_cant_we_switch_him(void *ptr) { switch (ptr) { case NULL: printf("NULL!\n"); break; default: printf("%p!\n", ptr); break; } } int main(void) { void *foo = "toast"; why_cant_we_switch_him(foo); return 0; } gcc test.c -o test test.c: In function 'why_cant_we_switch_him': test.c:5: error: switch quantity not an integer test.c:6: error: pointers are not permitted as case values Just curious. Is this a technical limitation? EDIT People seem to think there is only one constant pointer expression. Is that is really true, though? For instance, here is a common paradigm in Objective-C (it is really only C aside from NSString, id and nil, which are merely a pointers, so it is still relevant — I just wanted to point out that there is, in fact, a common use for it, despite this being only a technical question): #include <stdio.h> #include <Foundation/Foundation.h> static NSString * const kMyConstantObject = @"Foo"; void why_cant_we_switch_him(id ptr) { switch (ptr) { case kMyConstantObject: // (Note that we are comparing pointers, not string values.) printf("We found him!\n"); break; case nil: printf("He appears to be nil (or NULL, whichever you prefer).\n"); break; default: printf("%p!\n", ptr); break; } } int main(void) { NSString *foo = @"toast"; why_cant_we_switch_him(foo); foo = kMyConstantObject; why_cant_we_switch_him(foo); return 0; } gcc test.c -o test -framework Foundation test.c: In function 'why_cant_we_switch_him': test.c:5: error: switch quantity not an integer test.c:6: error: pointers are not permitted as case values It appears that the reason is that switch only allows integral values (as the compiler warning said). So I suppose a better question would be to ask why this is the case? (though it is probably too late now.)

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  • Oracle - Determine maximum supported size for regular expression

    - by FrustratedWithFormsDesigner
    I have a regular expression that throws ORA-12733, "regular expression is too long". How do I determine what the maximum supported size is? FYI: the offending regex is 892 characters. It's a generated regex, so I could change how I generate and execute it, but I would like to know what the limits to the max size are before I change how I am generating and executing. (running Oracle 10.2g) UPDATE: If it depends on the actual regex, here's the begining of it (the rest is just the same thing repeated, with different values between ^ and $): (^R_1A$|^R_2A$|^R_3A$|^R_4A$|^R_4B$|^R_5A$|^R_5B$...

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  • What doesn't MySQL do? [closed]

    - by sean riley
    When using MySQL 5.1 Enterprise after years of using other database products like Sybase, Infomix, DB2; I run into things that MySQL just doesn't do. For example, it can only generate an EXPLAIN query plan for SELECT queries. What are the other things I should watch out for?

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  • Is there any Limitation on loading native google map in android?

    - by captainpirate
    I have the following code to load native google map app into my project: final Intent intent = new Intent(Intent.ACTION_VIEW, Uri .parse("http://maps.google.com/maps?" + "saddr=43.0054446,-87.9678884" + "&daddr=42.9257104,-88.0508355")); intent.setClassName("com.google.android.apps.maps", "com.google.android.maps.MapsActivity"); startActivity(intent); Is there any limitation or pre-requisties there i should know. Because its working in my laptop emulator but not working on PC emulator. I only load the native google map app, it should work on any emulator. Is something i am missing here ??

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  • Is there a limitation to the length of the query in mysql?

    - by Bakhtiyor
    I am asking this question because I need to know this limitation as I am generating SELECT query in my PHP script and the part of WHERE in this query is generated inside the loop. Precisely it looks like this $query="SELECT field_names FROM table_name WHERE "; $condition="metadata like \"%$uol_metadata_arr[0]%\" "; for($i=1; $i<count($uol_metadata_arr); $i++){ $condition.=" OR metadata like \"%$uol_metadata_arr[$i]%\" "; } $query.=$condition; $result=mysql_query($query); So, that's why I need to know how long my $query string can be, because the array *$uol_metadata_arr* could contain many items.

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  • What are the app file size limitations for different smartphone OSes & carriers?

    - by Nick Gotch
    I know the iPhone App Store limits how large an app can be in general and there are also limitations with AT&T over the size it can be to transmit over a data plan vs WiFi. I have no idea what, if any, these limits are for Android apps and what I'm finding online is a mix of different numbers. Does anyone know these numbers definitively? The Android game I'm porting is in the 20-30MB range and we'd like to know if we need to further reduce its size.

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  • Quels sont vos astuces pour passer outre les limitations des EDI ? Comme marquer des arrêts dans un code volumineux sans points d'arrêt

    Quels sont vos trucs et astuces pour passer outre les limitations des EDI ? Comme marquer des arrêts dans un code volumineux sans points d'arrêt Les applications contenant des fichiers de source avec des lignes de code volumineux sont très souvent sujet à des dysfonctionnements. Les développeurs souhaitent alors retrouver rapidement le bloc ou la ligne qui ne s'exécute pas correctement. Plusieurs techniques et outils permettent d'effectuer le débogage d'un programme et d'observer son fonctionnement pour apporter des corrections de bugs ou faire des optimisations. Parmi eux, les points d'arrêt (breakpoints) sont très utilisés. Un point d'arrêt peut être vu comme un signal qui indiq...

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  • What are the advantages and limitations of using Qt for game development? [on hold]

    - by Gagege
    I know there is already a thread asking for example 3d games written using Qt. What I'd like to have a discussion about is whether or not Qt is a good framework for game development. In my experience Qt is a joy to work with and thanks to QML and QML/3d it's looking like it could be a viable framework for game development. The thought of using signals and slots for gamedev is exciting. I'd like to hear some opinions on Qt in general as a game development platform. What are it's limitations? What are it's advantages? Edit: I found an official Qt game development forum.

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