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  • ActiveRecord table inheritence using set_table_names

    - by Jinyoung Kim
    Hi, I'm using ActiveRecord in Ruby on Rails. I have a table named documents(Document class) and I want to have another table data_documents(DataDocument) class which is effectively the same except for having different table name. In other words, I want two tables with the same behavior except for table name. class DataDocument < Document #set_table_name "data_documents" self.table_name = "data_documents" end My solution was to use class inheritance as above, yet this resulted in inconsistent SQL statement for create operation where there are both 'documents' table and 'data_documents' table. Can you figure out why and how I can make it work? >> DataDocument.create(:did=>"dd") ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'data_documents.did' in 'where clause': SELECT `documents`.id FROM `documents` WHERE (`data_documents`.`did` = BINARY 'dd') LIMIT 1 from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:320:in `execute' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:595:in `select' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:62:in `select_all'

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  • SQL Query - group by more than one column, but distinct

    - by Ranhiru
    I have a bidding table, as follows: SellID INT FOREIGN KEY REFERENCES SellItem(SellID), CusID INT FOREIGN KEY REFERENCES Customer(CusID), Amount FLOAT NOT NULL, BidTime DATETIME DEFAULT getdate() Now in my website I need to show the user the current bids; only the highest bid but without repeating the same user. SELECT CusID, Max(Amount) FROM Bid WHERE SellID = 10 GROUP BY CusID ORDER BY Max(Amount) DESC This is the best I have achieved so far. This gives the CusID of each user with the maximum bid and it is ordered ascending. But I need to get the BidTime for each result as well. When I try to put the BidTime in to the query: SELECT CusID, Max(Amount), BidTime FROM Bid WHERE SellID = 10 GROUP BY CusID ORDER BY Max(Amount) DESC I am told that "Column 'Bid.BidTime' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause." Thus I tried: SELECT CusID, Max(Amount), BidTime FROM Bid WHERE SellID = 10 GROUP BY CusID, BidTime ORDER BY Max(Amount) DESC But this returns all the rows. No distinction. Any suggestions on solving this issue?

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  • Table comment length in mysql

    - by azerole
    According to MySQL manual, table comments are limited to 60 characters. I'm designing the schema in MySQL Workbench, which does not enforce this limit, so I end up with writing more than 60 symbols quite often, and this causes the SQL script to fail. To tell the truth I would be quite happy with table comments being internal to my schema (i.e. not exported to the actual database), but Workbench doesn't allow this either. Hence my question: is there a way to increase maximum length of table comment in MySQL to 255?

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  • How to prevent DOS attacks using image resizing in an ASP.NET application?

    - by Waleed Eissa
    I'm currently developing a site where users can upload images to use as avatars, I know this makes me sound a little paranoid but I was wondering what if a malicious user uploads an image with incredibly large dimensions that will eat the server memory (as a DOS attack), I already have a limit on the file size that can be uploaded (250 k) but even that size can allow for an image with incredibly large dimensions if the image for example is a JPEG that contains one color and created with a very low quality setting. Taking into consideration that the image is uploaded as a bitmap in memory when being resized (ie. not compressed), I wonder if such DOS attacks occur, even to check the image dimensions it has to be uploaded in memory first, did you hear about any attacks that exploited this? Am I too worried?

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  • Coding guidelines + Best Practices?

    - by Chathuranga Chandrasekara
    I couldn't find any question that directly applies to my query so I am posting this as a new question. If there is any existing discussion that may help me, please point it out and close the question. Question: I am going to do a presentation on C# coding guidelines but it is not supposed to limit to coding standards. So I have a rough idea but I think I need to address good programing practices. So the contents will be something like this. Basic coding standards - Casing, Formatting etc. Good practices - Usage of Hashset over other data structures, String vs String Builder, String's immutability and using them effectively etc Really I would like to add more good practices (Especially to improve the performance.) So like to hear some more good practices to be used with C#. Any suggestions??? (No need of large descriptions :) Just the idea is sufficient.)

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  • Safe non-tamperable URL component in Perl using symmetric encryption?

    - by Randal Schwartz
    OK, I'm probably just having a bad Monday, but I have the following need and I'm seeing lots of partial solutions but I'm sure I'm not the first person to need this, so I'm wondering if I'm missing the obvious. $client has 50 to 500 bytes worth of binary data that must be inserted into the middle of a URL and roundtrip to their customer's browser. Since it's part of the URL, we're up against the 1K "theoretical" limit of a GET URL. Also, $client doesn't want their customer decoding the data, or tampering with it without detection. $client would also prefer not to store anything server-side, so this must be completely standalone. Must be Perl code, and fast, in both encoding and decoding. I think the last step can be base64. But what are the steps for encryption and hashing that make the most sense?

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  • pubsub link with Project Rome

    - by itsadok
    I want to use Project Rome to create an RSS feed, using the code from the tutorial as base. I would like to add a pubsubhubbub discovery link, but there doesn't seem to be a general way to do so. I can use a Link object if I create an atom feed (which I don't want to limit myself to), or I can just add foreign markup, like this: // import org.jdom.Element Element element = new Element("link"); element.setAttribute("rel", "hub"); element.setAttribute("href", "https://myhub.example.com/endpoint"); feed.setForeignMarkup(Arrays.asList(element)); But it feels ugly. Is this really the best way to do this?

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  • Filtering model results for Django admin select box

    - by blcArmadillo
    I just started playing with Django today and so far am finding it rather difficult to do simple things. What I'm struggling with right now is filtering a list of status types. The StatusTypes model is: class StatusTypes(models.Model): status = models.CharField(max_length=50) type = models.IntegerField() def __unicode__(self): return self.status class Meta: db_table = u'status_types' In one admin page I need all the results where type = 0 and in another I'll need all the results where type = 1 so I can't just limit it from within the model. How would I go about doing this?

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  • Why does Google's Closure Compiler leave a few unnecessary spaces or line breaks?

    - by Bungle
    I've noticed that every time I use Google's Closure Compiler Service, it leaves a few unnecessary spaces in the compiled code presented on the right-hand side of the page. These correspond to line breaks in the hosted version of the compiled code. For example (note the line breaks, each of which seems unnecessary): http://troy.onespot.com/static/stack_overflow/closure_spaces.js To date, I've just been removing them manually, but I'm curious why they're there. Is it to limit the line length of the hosted version of the code to make it more readable? Could the compiler be smart enough to leave or insert those intentionally to maximize GZIP compression efforts? I know that they have a trivial effect on the file size, but with so much effort going into minifying every last byte in the source script, it's counterintuitive why they're there.

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  • question about InnoDB deadlock in MySQL?

    - by WilliamLou
    I found this kind of interesting problem in MySQL InnoDB engine, could anyone explain why the engine always claim it's a deadlock. First, I created a table with a single row, single column: CREATE TABLE `SeqNum` (`current_seq_num` bigint(30) NOT NULL default '0', PRIMARY KEY (`current_seq_num`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 | Now, I have two MySQL connector threads, In thread1: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; Query OK, 1 row affected (0.00 sec) Now, in thread2, I did the exactly same: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; before the default innodb_lock_wait_timeout, the thread2 just wait for thread1 to release its exclusive lock on the table, and it's normal. However, in thread1, if I input the following update query: mysql> update SeqNum set `current_seq_num` = 8; ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction Now, thread2 get the select query finished because thread1 quits. In addition, in thread1, if I input the update query with a where clause, it can be executed very well: mysql> update SeqNum set `current_seq_num` = 8 where `current_seq_num` =5 Query OK, 1 row affected (0.00 sec) Could anyone explain this?

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  • Replicating SQL's 'Join' in Python

    - by Daniel Mathews
    I'm in the process of trying to switch from R to Python (mainly issues around general flexibility). With Numpy, matplotlib and ipython, I've am able to cover all my use cases save for merging 'datasets'. I would like to simulate SQL's join by clause (inner, outer, full) purely in python. R handles this with the 'merge' function. I've tried the numpy.lib.recfunctions join_by, but it critical issues with duplicates along the 'key': join_by(key, r1, r2, jointype='inner', r1postfix='1', r2postfix='2', defaults=None, usemask=True, asrecarray=False) Join arrays r1 and r2 on key key. The key should be either a string or a sequence of string corresponding to the fields used to join the array. An exception is raised if the key field cannot be found in the two input arrays. Neither r1 nor r2 should have any duplicates along key: the presence of duplicates will make the output quite unreliable. Note that duplicates are not looked for by the algorithm. source: http://presbrey.mit.edu:1234/numpy.lib.recfunctions.html Any pointers or help will be most appreciated!

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  • Prevent password leakage while using sql* loader

    - by Jai
    I have shell script calling Sql*loader utility which inturn uses username/password as arguments. This details cannot be stored on server in any form due to security related policies. i got 2 approaches to handle this situation, 1. create hidden parameter file with login details and limit the access to owner. again the implication is i cannot store login data in any format on server 2. Create the user as OS authenticated and straight away login into sql without any userid/password I am not able to figure out risks involved in 2nd approach which u experienced folks could have come across. let me know if there is any other approach to handle password leakage issue

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  • Multithreaded program in C: calculating thread stack space

    - by SlappyTheFish
    Situation: I am writing a program in C that maintains a number of threads. Once a thread ends, a new one is created. Each thread forks - the child runs a PHP process via exec() and the parent waits for it to finish. Each PHP process takes the next item from a queue, processes it and exits. Basic code: http://www.4pmp.com/2010/03/multitasking-php-in-parallel/ Problem: The PHP processes are Symfony tasks and Symfony requires a fairly huge amount of memory. How can I safely calculate the required stack space for each thread so that PHP processes will have enough memory? The memory limit set in php.ini is 128Mb so should I allocate this much space in the stack?

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  • PLPGSQL : How to return a record from function executed by INSERT/UPDATE rule?

    - by seas
    Do the following scheme for my database: create sequence data_sequence; create table data_table { id integer primary key; field varchar(100); }; create view data_view as select id, field from data_table; create function data_insert(_new data_view) returns data_view as $$declare _id integer; _result data_view%rowtype; begin _id := nextval('data_sequence'); insert into data_table(id, field) values(_id, _new.field); select * into _result from data_view where id = _id; return _result; end; $$ language plpgsql; create rule insert as on insert to data_view do instead select data_insert(new); Then type in psql: insert into data_view(field) values('abc'); Would like to see something like: id | field ----+--------- 1 | abc Instead see: data_insert ------------- (1, "abc") Is it possible to fix this somehow? Thanks for any ideas. Ultimate idea is to use this in other functions, so that I could obtain id of just inserted record without selecting for it from scratch. Something like: insert into data_view(field) values('abc') returning id into my_variable would be nice but doesn't work with error: ERROR: cannot perform INSERT RETURNING on relation "data_view" HINT: You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause. I don't really understand that HINT. I use PostgreSQL 8.4.

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  • TCP Flow control in AS3?

    - by Jeremy Stanley
    I am currently working on a Flash socket client for a pre-existing service/standard. The service uses TCP flow control to throttle itself and the Flash socket is reading in everything as fast as it can despite not being able to process it as fast as it's being taken in. This causes the bytesAvailable on the socket to keep increasing and the server never knows that the client has fallen behind. In short, is there any way to limit the size of bytesAvailable for a Flash Socket object or throttle it in some other way? Note: Rewriting the server isn't a viable option at the current time as it's a standard and the client's utility drops immensely if server-side changes are needed

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  • findManyToManyRowset with Zend_Db_Table_Select

    - by Typeoneerror
    Hello. I'm trying to use a select object to filter the results of a many to many rowset. This call works great: $articles = $this->model->findArticlesViaArticlesUsers(); This however does not: $articles = new Default_Model_Articles(); $articleSelect = $articles->select(); $articleSelect->where("status = 'published'") ->order("date_published DESC") ->limit(1); $articles = $this->model->findArticlesViaArticlesUsers($articleSelect); That throws the following error: exception 'Zend_Db_Select_Exception' with message 'You cannot define a correlation name 'i' more than once' I can't figure out how to successfully get "articles that have the status of 'published'" using the magic many-to-many relationship (nor findManyToManyRowset). I'm at the end of my rope and thinking of just writing the sql manually. Any ideas?

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  • PHP-GD: Dealing with Unicode characters

    - by sehugg
    I am developing a web service that renders characters using the PHP GD extension, using a user-selected TTF font. This works fine in ASCII-land, but there are a few problems: The string to be rendered comes in as UTF-8. I would like to limit the list of user-selectable fonts to be only those which can render the string properly, as some fonts only have glyphs for ASCII characters, ISO 8601, etc. In the case where some decorative characters are included, it would be fine to render the majority of characters in the selected font and render the decorative characters in Arial (or whatever font contains the extended glyphs). It does not seem like PHP-GD has support for querying the font metadata sufficiently to figure out if a character can be rendered in a given font. What is a good way to get font metrics into PHP? Is there a command-line utility that can dump in XML or other parsable format?

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  • Free SWF Obfuscator

    - by Cyclone
    Does anybody know of a free flash obfuscator? All I can find are commercial ones with free trials. I have done numerous google searches, and have been unable to find what I am looking for. I know that obfuscators do not make your swf hack proof, but they make things harder. Things I am looking for in an obfuscator: Unlimited obfuscations No time limit No watermark (or on the left side only! Right side is no good, same with center) Able to publish work (no special player needed other than standard flashplayer) I really was surprised to see how hard it was to find a good obfuscator (tried encoder, protection, etc. instead as well) and how easy it is to find a decompiler.... It is imperative that my code be protected, at least partially, to discourage the hacking of my game.

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  • Yahoo YQL Rate Limits

    - by catlan
    I'm a bit unsure about the Usage Information and Limits of Yahoo YQL. Per application limit (identified by your Access Key): 100,000 calls per day. Per IP limits: /v1/public/: 1,000 calls per hour; /v1/yql/: 10,000 calls per hour. Do I require an application/access key for the /v1/public/ interface, non of the examples uses one. If I don't need an application key and only access the /v1/public/ interface I only have do worry about the IP limits of 1,000 calls per hour, right?

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  • Getting empty result within PHP when in browser I get the JSON exception

    - by Pentium10
    I have this code: $url="https://graph.facebook.com/me/friends?access_token=".$access_token."&fields=id,first_name,last_name&limit=10"; $content=file_get_contents($url); Whenever I use this on a non authenticated user I should get feedback of OAuthException, which doesn't show up in the PHP the $content is empty. While if I copy the URL to the browser I get the result and I see the exception. I want to detect if the user is logged in and the session data is valid. What might be wrong?

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  • How to store user preferences? Cookie becomes bigger..

    - by ari
    My application (Asp.Net MVC) has great interaction with the user interface (jQuery/js). For example, setting various searches charts, moving the gadgets on the screen and more .. I of course want to keep all data for each user. So that data will be available from any page in the Dumaine and the user will accepts his preferences. Now I keep all data in a cookie because it did not seem logical asynchronous access to the server each time the user changes something and thet happens a lot.When the user logout from the application I save the cookie to the database. The problem is the cookie becomes very large. The thought that this huge cookie is attached to each server request makes me feel that my attitude is wrong. Another problem cookies have size limit. It varies from your browser but I definitely have been close to the border - my cookie easily become 4kb Is there another solution?

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  • Optimising SQL distance query

    - by Alex
    I'm running an MySQL query that returns results based on location. However I have noticed recently that its really slowing down my PHP app. I used CodeIgniter and the profiler shows the query taking 4.2seconds. The geoname table has 500,000 rows. I have some indexes on the key columns, how else can speed up this query? Here is my SQL: SELECT `products`.`product_name`, `geoname`.`geonameid`, `geoname`.`latitude`, `geoname`.`longitude`, `products`.`product_id`, AVG(ratings.vote) as rating, count(comments.comment_id) as total_comments, (6371 * acos(cos(radians(38.7666667)) * cos(radians(geoname.latitude)) * cos(radians(geoname.longitude) - radians(-3.3833333)) + sin(radians(38.7666667)) * sin(radians(geoname.latitude)))) AS distance FROM (`foods`) JOIN `geoname` ON `geoname`.`geonameid` = `products`.`geoname_id` LEFT JOIN `ratings` ON `ratings`.`var_id` = `products`.`product_id` LEFT JOIN `comments` ON `comments`.`var_id` = `products `.`product_id` WHERE `products`.`product_id` != 82 GROUP BY `products`.`product_id` HAVING `distance` < 99 ORDER BY `distance` LIMIT 10

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  • Image Uploading - security issues

    - by TenaciousImpy
    Hi, I'm developing an ASP.NET Web app and would like the user to be able to either upload an image from their local system, or pass in a URL to an image. The image can either be a JPG or PNG. What security issues should I be concerned about doing this? I've seen various ways of embedding code within JPG files. Are there any methods in C# (or external libraries) which can confirm that a file is a JPG/PNG, otherwise throw an error? At the very least, I'm making the directory which holds uploaded images non-browsable and putting a max size limit of 1mb, but I'd like to implement further checks. Thanks for any advice.

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  • RSA encryption results in server execution timeout

    - by Nilambari
    Hi, I am using PHP Crypt_RSA (http://pear.php.net/package/Crypt_RSA) for encrypting and decrypting the contents. Contents are of 1kb size. Following are the results: keylength = 1024 Encryption function takes time: 225 secs keylength = 2048 Encryption function takes time: 115 secs I need to reduce this execution time as most of the live apache servers have 120 sec limit for execution time. How to reduce this execution time? RSA alorithm docs says the only 1024 - 2048 keys are generated. I ACTUALLY tried to generate larger key, but it always results in execution timeout. How do i work on reducing encryption - decryption execution time? Thanks, Nila

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  • Is there a PHP library that performs MySQL Data Validation and Sanitization According to Column Type

    - by JW
    Do you know of any open source library or framework that can perform some basic validation and escaping functionality for a MySQL Db. i envisage something along the lines of: //give it something to perform the quote() quoteInto() methods $lib->setSanitizor($MyZend_DBAdaptor); //tell it structure of the table - colnames/coltypes/ etc $lib->setTableDescription($tableDescArray); //use it to validate and escape according to coltype foreach ($prospectiveData as $colName => $rawValue) if ( $lib->isValid($colName, $rawValue)) { //add it to the set clause $setValuesArray[$lib->escapeIdentifier($colName);] = $lib->getEscapedValue($colName,$rawValue); } else { throw new Exception($colName->getErrorMessage()); } etc... I have looked into - Zend_Db_Table (which knows about a table's description), and - Zend_Db_Adaptor (which knows how to escape/sanitize values depending on TYPE) but they do not automatically do any clever stuff during updates/inserts Anyone know of a good PHP library to preform this kind of validation that I could use rather than writing my own? i envisage alot of this kind of stuff: ... elseif (eregi('^INT|^INTEGER',$dataset_element_arr[col_type])) { $datatype='int'; if (eregi('unsigned',$dataset_element_arr[col_type])) { $int_max_val=4294967296; $int_min_val=0; } else { $int_max_val=2147483647; $int_min_val=-2147483648; } } (p.s I know eregi is deprecated - its just an example of laborious code)

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