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  • trying to use ActiveRecord with Sinatra, Migration fails question

    - by David Lazar
    Hi, running Sinatra 1.0, I wanted to add a database table to my program. In my Rakefile I have a task task :environment do ActiveRecord::Base.establish_connection(YAML::load(File.open('config/database.yml'))["development"]) end I have a migration task in my namespace that calls the migration code: namespace :related_products do desc "run any migrations we may have in db/migrate" task :migrate => :environment do ActiveRecord::Migrator.migrate('db/migrate', ENV["VERSION"] ? ENV["VERSION"].to_i : nil ) end My console pukes out an error when the call to ActiveRecord::MIgrator.migrate() is made. rake aborted! undefined method `info' for nil:NilClass The migration code itself is pretty simple... and presents me with no clues as to what this missing info class is. class CreateStores < ActiveRecord::Migration def self.up create_table :stores do |t| t.string :name t.string :access_url t.timestamps end end def self.down drop_table :stores end end I am a little mystified here and am looking for some clues as to what might be wrong. Thanks!

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  • pointer and reference question (linked lists)

    - by sil3nt
    Hi there, I have the following code struct Node { int accnumber; float balance; Node *next; }; Node *A, *B; int main() { A = NULL; B = NULL; AddNode(A, 123, 99.87); AddNode(B, 789, 52.64); etc… } void AddNode(Node * & listpointer, int a, float b) { // add a new node to the FRONT of the list Node *temp; temp = new Node; temp->accnumber = a; temp->balance = b; temp->next = listpointer; listpointer = temp; } in this here void AddNode(Node * & listpointer, int a, float b) { what does *& listpointer mean exactly.

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  • Silverlight 4 NewBie Question

    - by codemnky
    I am watching a video from Silverlight.net website about DataForm. There is no source code download, so I am typing in the code as I watch the video. Unfortunately I can't replicate what is shown in the video. there are several issues. I am going to list out only the first 2 1) The presenter shows a simple class inside DataForm that has a icon at the very top of the data form that upon clicking it makes the DataForm editable and a save button appears at the bottom. I did'nt get the same thing when I ran my code against Silverlight 4 or Silverlight 3 2) Than he goes on to show that if you mark your class [Bindable(false)] you shouldn't see anything in your page. I did that but my form still shows all the properties I stopped after these 2 issues. If the features being talked about in this video were deprecated in the final release than this video should have been taken off the site. can anyone help me with this??

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  • Quick question about open_basedir

    - by Gio
    Hello, On my server, I have following setting: open_basedir /home/ :/usr/lib/php :/usr/local/lib/php :/tmp/ :/usr/local/ :/usr/bin Now, I am little bit confused about ending / in the / home / setting, does that mean that all subfolders inside home have same rights? or does it mean that only home files can be accessed? So, basically what is the main difference between: /home/ and /home With example if possible Thank you in advance.

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  • Basic Hibernate Caching Question

    - by manyxcxi
    Doe Hibernate use cache (second level or otherwise) if all I am doing is batch inserts? No entities are being requested from the database, and no generators are used. Also, would StatelessSession vs Session change the answer? What if I was using a Session with a JDBC batch size of 50? The cache I will be using is Ehcache

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  • Question about a http form GET method, using query arguments

    - by Lasse V. Karlsen
    I am looking at a bug in WebSVN where when I get into a file log and click on compare, it looses the repository name as part of the request. The details are unimportant. However, I've tracked down the bug to a http form that looks like this: <form method="get" action="comp.php?repname=Binaries&amp;" id="compare"> .... <input type="hidden" name="KEY" value="VALUE"> Is this supposed to work? Will both the "repname" argument, specified as part of the URL, and the hidden value be sent? It seems Chrome 4.1 only sends the hidden argument, and removes the repname parameter altogether. Is this correct? I fixed it temporarily, pending more information, by adding another hidden field for repname with the same value, and now everything works, I'm just wondering if Chrome or WebSVN is in fault here.

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  • Excel Question: I need a date and time formula to convert between time zones

    - by Harold Nottingham
    Hello, I am trying to find a way to calculate a duration in days between my, time zone (Central), and (Pacific; Mountain; Eastern). Just do not know where to start. My criteria would be as follows: Cell C5:C100 would be the timestamps in this format:3/18/2010 23:45 but for different dates and times. Cell D5:D100 would be the corresponding timezone in text form: Pacific; Mountain; Eastern; Central. Cell F5 would be where the duration in days would need to be. Just not sure how to write the formula to give me what I am looking for. I appreciate any assistance in advance. Thanks

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  • question about MySQL database migration

    - by WilliamLou
    Hi there: If I have a MySQL database with several tables on a live server, now I would like to migrate this database to another server. Of course, the migration I mean here involves some database tables, for example: add some new columns to several tables, add some new tables etc.. Now, the only method I can think of is to use some php/python(two scripts I know) script, connect two databases, dump the data from the old database, and then write into the new database. However, this method is not efficient at all. For example: in old database, table A has 28 columns; in new database, table A has 29 columns, but the extra column will have default value 0 for all the old rows. My script still needs to dump the data row by row and insert each row into the new database. Is there any tools or a better method than writing a script yourself? Here, I dont need to worry about multithread writing problems etc.., I mean the old database will be down (not open to public usage etc.., only for upgrade ) for a while. Thanks!!

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  • Java application design question

    - by ring bearer
    I have a hobby project, which is basically to maintain 'todo' tasks in the way I like. One task can be described as: public class TodoItem { private String subject; private Date dueBy; private Date startBy; private Priority priority; private String category; private Status status; private String notes; } As you can imagine I would have 1000s of todo items at a given time. What is the best strategy to store a todo item? (currently on an XML file) such that all the items are loaded quickly up on app start up(the application shows kind of a dashboard of all the items at start up)? What is the best way to design its back-end so that it can be ported to Android/or a J2ME based phone? Currently this is done using Java Swing. What should I concentrate on so that it works efficiently on a device where memory is limited? The application throws open a form to enter new todo task. For now, I would like to save the newly added task to my-todos.xml once the user presses "save" button. What are the common ways to append such a change to an existing XML file?(note that I don't want to read the whole file again and then persist)

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  • vestal_versions and htmldiff question of reversion...

    - by holden
    I'm guessing there's probably an easier way to do what I'm doing so that the code is less unwieldy. I had trouble understanding how to use the revert_to method... i wanted something where i could call up two different versions at the same time, but this doesn't seem to be the way that vestal_versions works. This code works, but I'm wondering if I'm making something harder than it needs to be and I'd like to find out before I delve deeper. @article = Article.find(params[:id]) if params[:versions] v = params[:versions].split(',') @article.revert_to(v.first.to_i) @content1 = @article.content @article.revert_to(v.last.to_i) @content2 = @article.content end In case you're wondering, I'm using this in conjunction with HTMLDIFF to get the version changes. <div id="content"> <% if params[:versions] %> <%= Article.diff(@content1, @content2) %> <% else %> <%= @article.content %> <% end %> </div>

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  • Systems design question: DB connection management in load-balanced n-tier

    - by aoven
    I'm wondering about the best approach to designing a DB connection manager for a load-balanced n-tier system. Classic n-tier looks like this: Client -> BusinessServer -> DBServer A load-balancing solution as I see it would then look like this: +--> ... +--+ +--> BusinessServer +--+--> SessionServer --+ Client -> Gateway --+--> BusinessServer +--| +--> DBServer +--> BusinessServer +--+--------------------+ +--> ... +--+ As pictured, the business server component is being load-balanced via multiple instances, and a hardware gateway is distributing the load among them. Session server probably needs to be situated outside the load-balancing array, because it manages state, which mustn't be duplicated. Barring any major errors in design so far, what is the best way to implement DB connection management? I've come up with a couple of options, but there may be others I'm not aware of: Introduce a new Broker component between the DBServer and the other components and let it handle the DB connections. The upside is that all the connections can be managed from a single point, which is very convenient. The downside is that now there is an additional "single point of failure" in the system. Other components must go through it for every request that involves DB in some way, which also makes this a bottleneck. Move the DB connection management into BusinessServer and SessionServer components and let each handle its own DB connections. The upside is that there is no additional "single point of failure" or bottleneck components. The downside is that there is also no control over possible conflicts and deadlocks apart from what DBServer itself can provide. What else can be done? FWIW: Technology is .NET, but none of the vendor-specific stacks are used (e.g. no WCF, MSMQ or the like).

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  • Silverlight4 Printing Question

    - by hallgato.attila
    Hello everyone! I'm having a problem with printing. Is it possible to print a (customized) DataGrid which doesn't fit the page? a) Using a ViewBox to make it fit one page. My problem here is that I can get the PrintableArea.Width and PrintableArea.Height in the PrintPage EventHandler, from the PrintPageEventArgs, but in that Event Handler I can't set the size of an UIElement before it gets printed. b) Multiple pages. Is it possible somehow to print the whole DataGrid, even the parts which are not visible (don't fit the page) and to somehow make the PrintableArea only a part of the DataGrid?

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  • Mysql Database Question about Large Columns

    - by murat
    Hi, I have a table that has 100.000 rows, and soon it will be doubled. The size of the database is currently 5 gb and most of them goes to one particular column, which is a text column for PDF files. We expect to have 20-30 GB or maybe 50 gb database after couple of month and this system will be used frequently. I have couple of questions regarding with this setup 1-) We are using innodb on every table, including users table etc. Is it better to use myisam on this table, where we store text version of the PDF files? (from memory usage /performance perspective) 2-) We use Sphinx for searching, however the data must be retrieved for highlighting. Highlighting is done via sphinx API but still we need to retrieve 10 rows in order to send it to Sphinx again. This 10 rows may allocate 50 mb memory, which is quite large. So I am planning to split these PDF files into chunks of 5 pages in the database, so these 100.000 rows will be around 3-4 million rows and couple of month later, instead of having 300.000-350.000 rows, we'll have 10 million rows to store text version of these PDF files. However, we will retrieve less pages, so again instead of retrieving 400 pages to send Sphinx for highlighting, we can retrieve 5 pages and it will have a big impact on the performance. Currently, when we search a term and retrieve PDF files that have more than 100 pages, the execution time is 0.3-0.35 seconds, however if we retrieve PDF files that have less than 5 pages, the execution time reduces to 0.06 seconds, and it also uses less memory. Do you think, this is a good trade-off? We will have million of rows instead of having 100k-200k rows but it will save memory and improve the performance. Is it a good approach to solve this problem and do you have any ideas how to overcome this problem? The text version of the data is used only for indexing and highlighting. So, we are very flexible. Thanks,

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  • basic c# question

    - by CoffeeCode
    why doesn't the element get swapped public static void SwapArray(ref int[,] arr) { for (int i = 0; i < arr.GetLength(0); i++) { for (int j = 0; j < arr.GetLength(0); j++) { int temp = arr[i, j]; arr[i, j] = arr[j, i]; arr[j, i] = temp; Console.Write(arr[i, j] + " "); } Console.WriteLine(); } } even if the parameter is without a ref modifier the array doesn't change. a copy of the reference is passed as a parameter right?

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  • Question about how to read the Safari/Chrome developer tool result

    - by richard
    Hi, I am using the developer tool in chrome (i think it is the same as safari). I did a timeline when I load wwww.yahoo.com. I attached the screen shot: http://yfrog.com/4jpicture2yyp You see: * Send Request (http://www.yahoo.com) * Receive Response (http://www.yahoo.com) * Receive Response (http://www.yahoo.com) * Event (unload) * Function Call * Recalculate Style * Recalculate Style * Recalculate Style * Parse What I don't understand is why 'Parse' happens AFTER Function call and Recalculate Style? Shouldn't it need to parse HTML source FIRST Before it parses CSS file (I assume which triggers the 'Recalculate Style') and Java Script file (I assume which triggers the 'Function Call')

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  • Question About DateCreated and DateModified Columns - MS SQL Server

    - by user311509
    CREATE TABLE Customer ( customerID int identity (500,20) CONSTRAINT . . dateCreated datetime DEFAULT GetDate() NOT NULL, dateModified datetime DEFAULT GetDate() NOT NULL ); When i insert a record, dateCreated and dateModified gets set to default date/time. When i update/modify the record, dateModified and dateCreated remains as is? What should i do? Obviously, i need to dateCreated value to remain as was inserted the first time and dateModified keeps changing when a change/modification occurs in the record fields. In other words, can you please write a sample quick trigger? I don't know much yet... Any help will be appreciated.

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  • Question About DateCreated and DateModified Columns - SQL Server

    - by user311509
    CREATE TABLE Customer ( customerID int identity (500,20) CONSTRAINT . . dateCreated datetime DEFAULT GetDate() NOT NULL, dateModified datetime DEFAULT GetDate() NOT NULL ); When i insert a record, dateCreated and dateModified gets set to default date/time. When i update/modify the record, dateModified and dateCreated remains as is? What should i do? Obviously, i need to dateCreated value to remain as was inserted the first time and dateModified keeps changing when a change/modification occurs in the record fields. In other words, can you please write a sample quick trigger? I don't know much yet...

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  • in app purchases question

    - by bdt
    I am looking into the iPhone in app purchased models and need to implement a subscription. Ex content will be available for 24 hours. Now the most important thing is that it needs to be available on all the other devices, so bought on the iPhone, viewable on the iPad. I'm not sure how this works ? I need to store some information on the developer server but is this the transaction id and current date/time so when launching the app on the iPad, you will attempt to buy the content again. Apple will see that this user already bought that and hopefully returns the transaction ID. At that moment I can verify if the time limit it still valid or not. Can anyone confirm this method off working? If this is correct is there a 'renew'?

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  • Objective-C Class Question?

    - by tarnfeld
    Hey, My head is about to explode with this logic, can anyone help? Class A #imports Class B. Class A calls Method A in Class B. This works great Class B wants to send a response back to Class A from another method that is called from Method A. If you #import Class A from Class B, it is in effect an infinite loop and the whole thing crashes. Is there a way to do this properly, like a parent type thing? BTW, I'm developing for iPhone.

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  • UITableViewCell outlets not set during bundle load (possibly very elementary question)

    - by Jan Zich
    What are the most common reasons for an outlet (a class property) not being set during a bundle load? I'm sorry; most likely I'm not using the correct terms. It's my first steps with iPhone OS development and Objective-C, so please bear with me. Here is more details. Basically, I'm trying to create a table view based form with a fixed number of static rows. I followed this example: http://developer.apple.com/iphone/library/documentation/userexperience/conceptual/TableView_iPhone/TableViewCells/TableViewCells.html Scroll down to The Technique for Static Row Content please. I have one nib file with one table view, three table cells and all connections set as in the example. The problem is that the corresponding cell properties in my controller are never initialised. I get an exception in cellForRowAtIndexPath complaining that the returned cell is nil: UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath. Here are the relevant parts from the implementation of the controller: @synthesize cellA; @synthesize cellB; @synthesize cellC; - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 3; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { switch (indexPath.row) { case 0: return cellA; break; case 1: return cellB; break; case 2: return cellC; break; default: return nil; } } And here is the interface part: @interface AssociatePhoneViewController : UITableViewController { UITableViewCell *cellA; UITableViewCell *cellB; UITableViewCell *cellB; } @property (nonatomic, retain) IBOutlet UITableViewCell *cellA; @property (nonatomic, retain) IBOutlet UITableViewCell *cellB; @property (nonatomic, retain) IBOutlet UITableViewCell *cellC; @end This must be possibly one of the the most embarrassing questions on StackOverflow. It looks like the most basic example code. Is is possible that the cells are not instantiated with the nib file? I have them on the same level before the tabula view in the nib file. I tried to move them after the table view, but it did not make any difference. Are table cells in some way special? Do I need to set some flag or some property on them in the nib file? I was under the impression that all classes (views, windows, controllers …) listed in a nib file are simply instantiated (and linked using the provided connections). Could it possibly be some memory issue? The cell properties in my controller are not defined in any special way.

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