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  • Errors when using a Ruby On Rails scaffold with a data type of interger

    - by bublebboy
    I am learning Ruby On Rails. I am on a shared hosting with Ruby version 1.8.1 and Rails version 2.3.10. I am working my way through a tutorial at http://railstutorial.org/chapters/a-demo-app?version=2.3#top and at one point in the tutorial it has me run: script/generate scaffold Micropost content:string user_id:interger The tutorial is using the default database, SQLite3. The command works and I use rake db:migrate to create the database. I can view the page listing the microposts (which is empty), but when I try to add a micropost (microposts/new) I get an error undefined method `user_id' for #<Micropost:0x7f710e4988e8> After doing some testing on my own it seems I experience the problem by using the data type of interger. While I understand that using a scaffold is not the best way of building a ruby on rails, I'm just beginning and would still like to know why I am experiencing this problem to help me better understand how rails works.

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  • embed multiple youtube videos to chromeless player cue

    - by Quaze
    So in the project ive been working on i use the youtube API to add a video to a chromeless player (got custom buttons, everything works no problems). It loads the youtube id which it gets from the database (Codeigniter, PHP). But what i would like to see is: instead of loading 1 video, id like to add all the videos i get from the database in the cue of that one player. So only one screen, first video retrieved from dbase gets played first, when its done second get loaded preferably also looped. Is there any way i can achieve this? My first guess would be to save the array with youtube id's somewhere and on state change (when the 'video stop'-event gets fired) load the next id from the array. Havent tried this yet because id prefer if the cue gets just gets filled on the init, so it doesnt have to load after a video has been ended. Is This possible?

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  • Javascript large number array compression

    - by gatapia
    Hi All, I've got a javascript application that sends a large amount of numerical data down the wire. This data is then stored in a database. I am having size issues (too much bandwidth, database getting too big). I am now ready to sacrifice some performance for compression. I was thinking of implementing a base 62 number.toString(62) and parseInt(compressed, 62). This would certainly reduce the size of the data but before I go ahead and do this I thought I would put it to the folks here as I know there must be some outside the box solution I have not considered. The basic specs are: - Compress large number arrays into strings for JSONP transfer (So I think UTF is out) - Be relatively fast, look I'm not expecting same performance as I have now but I also don't want gzip compression either. Any ideas would be greatly appreciated. Thanks Guido Tapia

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  • Need help with formulating LINQ query

    - by eponymous23
    I'm building a word anagram program that uses a database which contains one simple table: Words --------------------- varchar(15) alphagram varchar(15) anagram (other fields omitted for brevity) An alphagram is the letters of a word arranged in alphabetical order. For example, the alphagram for OVERFLOW would be EFLOORVW. Every Alphagram in my database has one or more Anagrams. Here's a sample data dump of my table: Alphagram Anagram EINORST NORITES EINORST OESTRIN EINORST ORIENTS EINORST STONIER ADEINRT ANTIRED ADEINRT DETRAIN ADEINRT TRAINED I'm trying to build a LINQ query that would return a list of Alphagrams along with their associated Anagrams. Is this possible?

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  • Restricting deletion with NHibernate

    - by FrontSvin
    I'm using NHibernate (fluent) to access an old third-party database with a bunch of tables, that are not related in any explicit way. That is a child tables does have parentID columns which contains the primary key of the parent table, but there are no foreign key relations ensuring these relations. Ideally I would like to add some foreign keys, but cannot touch the database schema. My application works fine, but I would really like impose a referential integrity rule that would prohibit deletion of parent objects if they have children, e.i. something similar 'ON DELETE RESTRICT' but maintained by NHibernate. Any ideas on how to approach this would be appreciated. Should I look into the OnDelete() method on the IInterceptor interface, or are there other ways to solve this? Of course any solution will come with a performance penalty, but I can live with that.

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  • Storing task state between multiple django processes

    - by user366148
    I am building a logging-bridge between rabbitmq messages and Django application to store background task state in the database for further investigation/review, also to make it possible to re-publish tasks via the Django admin interface. I guess it's nothing fancy, just a standard Producer-Consumer pattern. Web application publishes to message queue and inserts initial task state into the database Consumer, which is a separate python process, handles the message and updates the task state depending on task output The problem is, some tasks are missing in the db and therefore never executed. I suspect it's because Consumer receives the message earlier than db commit is performed. So basically, returning from Model.save() doesn't mean the transaction has ended and the whole communication breaks. Is there any way I could fix this? Maybe some kind of post_transaction signal I could use? Thank you in advance.

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  • Storing Data as XML BLOB

    - by NBrowne
    Hi, At the moment the team i am working with is looking into the possibility of storing data which is entered by users from a series of input wizard screens as an XML blob in the database. the main reason for this being that i would like to write the input wizard as a component which can be brought into a number of systems without having to bring with it a large table structure. To try to clarify if the wizard has 100 input fields (for example) then if i go with the normal relational db structure then their will be a 1 to 1 relationship so will have 100 columns in database. So to get this working in another system will have to bring the tables,strore procedures etc into the new system. I have a number of reservations about this but i would like peoples opinions?? thanks

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  • Creating user generated reports

    - by Marquinio
    Hello Everyone, I need users to create custom reports. These users do not know any technical skills like SQL. We currently have a custom database report design. So basically whatever the user does on the GUI the application will have to generate the appropriate SQL to generate the report structure. Has anyone done this before? I know there are reporting solutions out there but we already have our own database tables for reporting. We already have a section where users can view reports displayed in HTML. Like for example if user selects a "UserID" and "Accounts" fields from GUI, how would I know that my SQL has to join the USER and ACCOUNTS table? I guess I'm just looking for some ideas to help me solve this problem. Thanks.

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  • Access 2007 Locking Issue - Attachments being overwritten...

    - by user456356
    We're currently running into an issue with an Access 2007 database for a client. They've got Excel 2007 documents attached to records within the database. Whenever changes to the document are made, they are overwriting each other, and we're not sure exactly why. This is happening with different records, and all of the attached documents are named differently. We've tried adjusting the different locking schemes, but this doesn't seem to resolve the issue. Any ideas? Are we missing something?

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  • How to use SQLiteOpenHelper without or less restrictive use of Context?

    - by Pentium10
    If you extend SQLiteOpenHelper, for the Constructor you have to use a Context. I am wondering if there is a way to leave this out, and be able to work with database tables without a Context. Or at least be least restrictive, I mean a way of project/class structure that will make history the several context passings I have to do now. As it is my application has several level of classes, chained in each other, and there are a few that connects to the database, but have no whatsoever influence on the interface, so they don't actually need the Context. Are you creating your classes in the way that you pass each time a Context to them? If not, how you do, how you reuse a Context in a short class?

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  • MySQL COUNT() multiple columns

    - by liam
    Hello, I'm trying to fetch the most popular tags from all videos in my database (ignoring blank tags). I also need the 'flv' for each tag. I have this working as I want if each video has one tag: SELECT tag_1, flv, COUNT(tag_1) AS tagcount FROM videos WHERE NOT tag_1='' GROUP BY tag_1 ORDER BY tagcount DESC LIMIT 0, 10 However in my database, each video is allowed three tags - tag_1, tag_2 and tag_3. Is there a way to get the most popular tags reading from multiple columns? The record structure is: +-----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | flv | varchar(150) | YES | | NULL | | | tag_1 | varchar(75) | YES | | NULL | | | tag_2 | varchar(75) | YES | | NULL | | | tag_3 | varchar(75) | YES | | NULL | | +-----------------+--------------+------+-----+---------+----------------+

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  • Design question?

    - by Mohamed
    I am building music app, where user can do several tasks including but not limited to listening song, like song, recommend song to a friend and extra. currently I have this model: class Activity(models.Model): activity = models.TextField() user = models.ForeignKey(User) date = models.DateTimeField(auto_now=True) so far I thought about two solutions. 1. saving a string to database. e.g "you listened song xyz" 2. create a dictionary about the activity and save to the database using pickle or json. e.g. dict_ = {"activity_type":"listening", "song":song_obj} I am leaning to the second implementation, but not quite sure. so what do you think about those two methods? do you know better way to achieve the goal?

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  • How do I include a newline in a text message sent as email from an ASP.Net application?

    - by Tim Goodman
    I have an ASP.Net Application that sends text messages to mobile phones. It does this by sending an email. For instance, if your phone number is 555-555-5555 and your wireless carrier is Verizon, you can send an email to [email protected] and it will show up as a text message. I want to be able to include a newline in the body of the message. How do I do this? Also please note that my ASP.Net program gets the message from a database (MS SQL Server) so what I really need to know is what characters to include in the message body when I store it in my database. I already tried \n but it just showed up in the text message as \n

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  • Getting the last element of a Postgres array, declaratively

    - by Wojciech Kaczmarek
    How to obtain the last element of the array in Postgres? I need to do it declaratively as I want to use it as a ORDER BY criteria. I wouldn't want to create a special PGSQL function for it, the less changes to the database the better in this case. In fact, what I want to do is to sort by the last word of a specific column containing multiple words. Changing the model is not an option here. In other words, I want to push Ruby's sort_by {|x| x.split[-1]} into the database level. I can split a value into array of words with Postgres string_to_array or regexp_split_to_array functions, then how to get its last element?

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  • How should I capture clickstream data?

    - by editor
    I'd like to start using clickstream analysis to improve a dynamic site's user experience. I'd like to rule out two options: parameterizing URLs (index.php?src=http://www.example.com) and immediate database logging. The former makes pretty ugly URLs and isn't great for SEO and the latter might slow down page render when there are lots of concurrent users. Assuming these aren't viable options, I think I'm left with doing an asynchronous POST to a server side script that runs a database query and returns a 204 (no data) response. Is this the best option for capturing clickstream data?

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  • importing data using get or create - identity error 1062

    - by hamackey
    I am importing data from a mssql database into mysql. Works except when it encounters the id of a previous entry. id is unique. I need to get entries that already exist so that they can be placed in the work of the day. Error is IntegrityError: (1062, "Duplicate entry '001355338' for key 2") This entry is already in the database. I need it entered for that day, but can not have it added to the table. It is already there. def handle(self, *args, **options): 59 #patients_local = Patient.objects.all() 60 #attendings_local = Attending.objects.all() 61 connection = pyodbc.connect("XXXXXXXXXXX") 62 cursor = connection.cursor() 63 cursor.execute(COMMAND) 64 rows = cursor.fetchall() 65 for row in rows: 66 # get_or_create returns (object, boolean) 67 p, created = Patient.objects.get_or_create( 68 first_name = row.Firstname, 69 middle_name = '', 70 last_name = row.Lastname, 71 id = row.id, 72 )

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  • Table Adaptor Error when trying update

    - by JasonMc92
    Hi, I have a rather perplexing issue. I am using VB.net and SQL for my project. I have a database, to which the connection works. I also have a data table and data adaptor, both of which I know work. I am trying to update something in the database, yet it isn't working. Assume everything listed is declared correctly. What am I doing wrong? teacher_control_table.Rows(0)("DATA_TeacherLockPasscode") = txtPasscode1.Text table_adaptor2.Update(teacher_control_table) That last line throws the following exception: InvalidOperationException was unhandled. update requires a valid UpdateCommand when passed DataRow collection with modified rows.

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  • Using memcached/APC for session storage?

    - by Industrial
    Hi everybody, I had some thoughts back ago about using memcached for session storage, but came to the conclusion that it wouldn't be sufficient in the event of one or more of the servers in the memcached pool were about to go down. A hybrid version is to save the main database (mySQL) from load caused by reads would be to work out a function that tries to fetch the data from the cache pool, and if that fails gets it from the database. After putting some more thought into it, I started to think about using APC cache for session related data. If our web server would go down, sessions would be lost either way, so storing them in a local APC or a localhost memcached server maybe isn't that bad? What's your experiences?

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  • Is there a way to launch an aggressive and complete garbage collection in Java?

    - by Gnoupi
    For memory optimization reasons, I'm launching myself the garbage collector during profiling, to check if objects are correctly cleaned after disposing of them. The call to garbage collector is not enough, though, and it seems that there is no guarantee of what it will clean. Is there a way to call it, to be sure it will recover as much as it can, in profiling conditions (this would have no point in production, of course)? Or is "calling it several times" the only way to be "almost sure"? Or did I simply misunderstand something about the Garbage Collector?

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  • sql: DELETE + INSERT vs UPDATE + INSERT

    - by user93422
    A similar question has been asked, but since it always depends, I'm asking for my specific situation separately. I have a web-site page that shows some data that comes from a database, and to generate the data from that database I have to do some fairly complex multiple joins queries. The data is being updated once a day (nightly). I would like to pre-generate the data for the said view to speed up the page access. For that I am creating a table that contains exact data I need. Question: for my situation, is it reasonable to do complete table wipe followed by insert? or should I do update,insert? SQL wise seems like DELETE + INSERT will be easier (it is single SQL expression). EDIT: RDBMS: MS SQL Server 2008 Ent

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  • Have an external java application by notified of changes to Entity EJBs in JBoss AS

    - by John
    I'm trying to connect an external application to a JBoss AS container. The external application is a Java application that is currently being notified of changes to database entities through a JMS topic. I've added an EntityLifecycleListener class to all my entities that publishes a serialized (and unwrapped) copy of the entity to the JMS topic. The problem is that this implementation ignores the transaction boundaries of the JBoss container. For example, the @PostUpdate event can be fire, generating the JMS message for that entity, but the transaction could be rolled back causing the external application to be notified of an invalid change and become unsync'd. I need my external application to only be notified of successful commits to the database, but I need to be able to publish the entire java POJO to the external application. Is there an official way of doing this?

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  • Will lock() statement block all threads in the proccess/appdomain?

    - by MikeJ
    Maybe the question sounds silly, but I don't understand 'something about threads and locking and I would like to get a confirmation (here's why I ask). So, if I have 10 servers and 10 request in the same time come to each server, that's 100 request across the farm. Without locking, thats 100 request to the database. If I do something like this: private static readonly object myLockHolder = new object(); if (Cache[key] == null) { lock(myLockHolder) { if (Cache[key] == null) { Cache[key] = LengthyDatabaseCall(); } } } How many database requests will I do? 10? 100? Or as much as I have threads?

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  • overlay items from mysql

    - by user1285471
    I have several locations in tables in a mysql database which i want to have displayed as POI's, the table is too large and changes too frequently to use sql lite so i need to get the info from mysql. I have set up a mapView indicating the device location in mapview using an image at drawable, but i now need to ad the other locations from the database. Then when a user clicks on an item i need a popup with options to route there using google maps navigation, or view mobi site, phone, or email. I am new to android. Please assist. Have gone through the overlay tut but no indication on how to get the info from db. Is there a tut somwhere so i can see some example code to do this?

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  • Can I replicate some of the optimisations done by the JVM by hand?

    - by Subb
    I'm working on a Sudoku solver at school and we're having a little performance contest. Right now, my algorithm is pretty fast on the first run (about 2.5ms), but even faster when I solve the same puzzle 10 000 times (about 0.5ms for each run). Those timing are, of course, depend of the puzzle being solved. I know the JVM do some optimization when a method is called multiple time, and this is what I suspect is happening. I don't think I can further optimize the algorithm itself (though I'll keep looking), so I was wondering if I could replicate some of the optimizations done by the JVM. Note : compiling to native code is not an option Thanks!

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  • Improving the performance of an nHibernate Data Access Layer.

    - by Amitabh
    I am working on improving the performance of DataAccess Layer of an existing Asp.Net Web Application. The scenerios are. Its a web based application in Asp.Net. DataAccess layer is built using NHibernate 1.2 and exposed as WCF Service. The Entity class is marked with DataContract. Lazy loading is not used and because of the eager-fetching of the relations there is huge no of database objects are loaded in the memory. No of hits to the database is also high. For example I profiled the application using NHProfiler and there were about 50+ sql calls to load one of the Entity object using the primary key. I also can not change code much as its an existing live application with no NUnit test cases at all. Please can I get some suggestions here?

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