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  • Can I use the auto-generated Linq-to-SQL entity classes in 'disconnected' mode?

    - by Gary McGill
    Suppose I have an automatically-generated Employee class based on the Employees table in my database. Now suppose that I want to pass employee data to a ShowAges method that will print out name & age for a list of employees. I'll retrieve the data for a given set of employees via a linq query, which will return me a set of Employee instances. I can then pass the Employee instances to the ShowAges method, which can access the Name & Age fields to get the data it needs. However, because my Employees table has relationships with various other tables in my database, my Employee class also has a Department field, a Manager field, etc. that provide access to related records in those other tables. If the ShowAges method were to invoke any of those methods, this would cause lots more data to be fetched from the database, on-demand. I want to be sure that the ShowAges method only uses the data I have already fetched for it, but I really don't want to have to go to the trouble of defining a new class which replicates the Employee class but has fewer methods. (In my real-world scenario, the class would have to be considerably more complex than the Employee class described here; it would have several 'joined' classes that do need to be populated, and others that don't). Is there a way to 'switch off' or 'disconnect' the Employees instances so that an attempt to access any property or related object that's not already populated will raise an exception? If not, then I assume that since this must be a common requirement, there might be an already-established pattern for doing this sort of thing?

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  • How can I use "Dependency Injection" in simple php functions, and should I bother?

    - by Tchalvak
    I hear people talking about dependency injection and the benefit of it all the time, but I don't really understand it. I'm wondering if it's a solution to the "I pass database connections as arguments all the time" problem. I tried reading wikipedia's entry on it, but the example is written in Java so I don't solidly understand the difference it is trying to make clear. ( http://en.wikipedia.org/wiki/Dependency_injection ). I read this dependency-injection-in-php article ( http://www.potstuck.com/2009/01/08/php-dependency-injection/ ), and it seems like the objective is to not pass dependencies to an object directly, but to cordon off the creation of an object along with the creation of it's dependencies. I'm not sure how to apply that in a using php functions context, though. Additionally, is the following Dependency Injection, and should I bother trying to do dependency injection in a functional context? Version 1: (the kind of code that I create, but don't like, every day) function get_data_from_database($database_connection){ $data = $database_connection->query('blah'); return $data; } Version 2: (don't have to pass a database connection, but perhaps not dependency injection?) function get_database_connection(){ static $db_connection; if($db_connection){ return $db_connection; } else { // create db_connection ... } } function get_data_from_database(){ $conn = get_database_connection(); $data = $conn->query('blah'); return $data; } $data = get_data_from_database(); Version 3: (the creation of the "object"/data is separate, and the database code is still, so perhaps this would count as dependency injection?) function factory_of_data_set(){ static $db_connection; $data_set = null; $db_connection = get_database_connection(); $data_set = $db_connection->query('blah'); return $data_set; } $data = factory_of_data_set(); Anyone have a good resource or just insight that makes the method and benefit -crystal- clear?

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  • c# web extracting programming, which libraries, examples samples please

    - by user287745
    I have just started programming and have made a few small applications in C and C#. My understanding is that programming for web and thing related to web is nowadays a very easy task. Please note this is for personnel learning, not for rent a coder or any money making. An application which can run on any Windows platform even Windows 98. The application should start automatically at a scheduled time and do the following. Connect to a site which displays stock prices summary (high low current open). Capture the data (excluding the other things in the site.) And save it to disk (an SQL database) Please note:- Internet connection is assumed to be there always. Do not want to know how to make database schema or database. The stock exchange has no law prohibiting the use of the data provided on its site, but I do not want to mention the name in case I am wrong, but it's for personal private use only. The data of summary of pricing is arranged in a table such that when copied pasted to MS Excel it automatically forms a table. need steps guidance please, examples, lbraries

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  • django powering multiple shops from one code base on a single domain

    - by imanc
    Hey, I am new to django and python and am trying to figure out how to modify an existing app to run multiple shops through a single domain. Django's sites middleware seems inappropriate in this particular case because it manages different domains, not sites run through the same domain, e.g. : domain.com/uk domain.com/us domain.com/es etc. Each site will need translated content - and minor template changes. The solution needs to be flexible enough to allow for easy modification of templates. The forms will also need to vary a bit, e.g minor variances in fields and validation for each country specific shop. I am thinking along the lines of the following as a solution and would love some feedback from experienced django-ers: In short: same codebase, but separate country specific urls files, separate templates and separate database Create a middleware class that does IP localisation, determines the country based on the URL and creates a database connection, e.g. /au/ will point to the au specific database and so on. in root urls.py have routes that point to a separate country specific routing file, e..g (r'^au/',include('urls_au')), (r'^es/',include('urls_es')), use a single template directory but in that directory have a localised directory structure, e.g. /base.html and /uk/base.html and write a custom template loader that looks for local templates first. (or have a separate directory for each shop and set the template directory path in middleware) use the django internationalisation to manage translation strings throughout slight variances in forms and models (e.g. ZA has an ID field, France has 'door code' and 'floor' etc.) I am unsure how to handle these variations but I suspect the tables will contain all fields but allowing nulls and the model will have all fields but allowing nulls. The forms will to be modified slightly for each shop. Anyway, I am keen to get feedback on the best way to go about achieving this multi site solution. It seems like it would work, but feels a bit "hackish" and I wonder if there's a more elegant way of getting this solution to work. Thanks, imanc

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  • Convert C# Silverlight App To AZURE CLOUD Platform?!?!

    - by Goober
    The Scenario I've been following Brad Abrams Silverlight tutorial on his blog.... I have tried following Brads "How to deploy your app to the Cloud" tutorial however i'm struggling with it, even though it is in the same context as the first tutorial.... The Question Is the application structure essentially the same as the original "non-cloud based version"!? If not, which parts are different? (I get that there is a Cloud Service project added to the solution) - but what else?! Connection String Issue In my "Non-Cloud based application", I make use of the ADO.Net Entity Framework to communicate with my database. The connection string in my web.config file looks like: <add name="InmZenEntities" connectionString="metadata=res://*/InmZenModel.csdl|res://*/InmZenModel.ssdl|res://*/InmZenModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=CHASEDIGITALWS3;Initial Catalog=InmarsatZenith;Integrated Security=True;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" /></connectionStrings> However However the connection string that I get from SQL AZURE looks like: Server=tcp:k12ioy1rsi.ctp.database.windows.net;Database=master;User ID=simongilbert;Password=myPassword;Trusted_Connection=False; So how do I go about merging the two when I move the "non-cloud based application" to THE CLOUD?! Any help regarding converting a silverlight application to a cloud service and deploying it would be greatly appreciated

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  • SqlCe odd results why? -- Same SQL, different results in different apps. Issue with

    - by NitroxDM
    When I run this SQl in my mobile app I get zero rows. select * from inventory WHERE [ITEMNUM] LIKE 'PUMP%' AND [LOCATION] = 'GARAGE' When I run the same SQL in Query Analyzer 3.5 using the same database I get my expected one row. Why the difference? Here is the code I'm using in the mobile app: SqlCeCommand cmd = new SqlCeCommand(Query); cmd.Connection = new SqlCeConnection("Data Source="+filePath+";Persist Security Info=False;"); DataTable tmpTable = new DataTable(); cmd.Connection.Open(); SqlCeDataReader tmpRdr = cmd.ExecuteReader(); if (tmpRdr.Read()) tmpTable.Load(tmpRdr); tmpRdr.Close(); cmd.Connection.Close(); return tmpTable; UPDATE: For the sake of trying I used the code found in one of the answers found here and it works as expected. So my code looks like this: SqlCeConnection conn = new SqlCeConnection("Data Source=" + filePath + ";Persist Security Info=False;"); DataTable tmpTable = new DataTable(); SqlCeDataAdapter AD = new SqlCeDataAdapter(Query, conn); AD.Fill(tmpTable); The issue appears to be with the SqlCeDataReader. Hope this helps someone else out!

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  • Using Linq2Sql to insert data into multiple tables using an auto incremented primary key

    - by Thomas
    I have a Customer table with a Primary key (int auto increment) and an Address table with a foreign key to the Customer table. I am trying to insert both rows into the database in one nice transaction. using (DatabaseDataContext db = new DatabaseDataContext()) { Customer newCustomer = new Customer() { Email = customer.Email }; Address b = new Address() { CustomerID = newCustomer.CustomerID, Address1 = billingAddress.Address1 }; db.Customers.InsertOnSubmit(newCustomer); db.Addresses.InsertOnSubmit(b); db.SubmitChanges(); } When I run this I was hoping that the Customer and Address table automatically had the correct keys in the database since the context knows this is an auto incremented key and will do two inserts with the right key in both tables. The only way I can get this to work would be to do SubmitChanges() on the Customer object first then create the address and do SubmitChanges() on that as well. This would create two roundtrips to the database and I would like to see if I can do this in one transaction. Is it possible? Thanks

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  • SQL Server Index cost

    - by yellowstar
    I have read that one of the tradeoffs for adding table indexes in SQL Server is the increased cost of insert/update/delete queries to benefit the performance of select queries. I can conceptually understand what happens in the case of an insert because SQL Server has to write entries into each index matching the new rows, but update and delete are a little more murky to me because I can't quite wrap my head around what the database engine has to do. Let's take DELETE as an example and assume I have the following schema (pardon the pseudo-SQL) TABLE Foo col1 int ,col2 int ,col3 int ,col4 int PRIMARY KEY (col1,col2) INDEX IX_1 col3 INCLUDE col4 Now, if I issue the statement DELETE FROM Foo WHERE col1=12 AND col2 > 34 I understand what the engine must do to update the table (or clustered index if you prefer). The index is set up to make it easy to find the range of rows to be removed and do so. However, at this point it also needs to update IX_1 and the query that I gave it gives no obvious efficient way for the database engine to find the rows to update. Is it forced to do a full index scan at this point? Does the engine read the rows from the clustered index first and generate a smarter internal delete against the index? It might help me to wrap my head around this if I understood better what is going on under the hood, but I guess my real question is this. I have a database that is spending a significant amount of time in delete and I'm trying to figure out what I can do about it. When I display the execution plan for the deletion, it just shows an entry for "Clustered Index Delete" on table Foo which lists in the details section the other indices that need to be updated but I don't get any indication of the relative cost of these other indices. Are they all equal in this case? Is there some way that I can estimate the impact of removing one or more of these indices without having to actually try it?

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  • Error // Usage: rails new APP_PATH [options] // when running 'rails server'

    - by madphill
    Background info: I'm using GIT to get a repository of a project with Ruby files in it. The project lives in my SITES folder under home directory on my Mac. I have Ruby: 1.8.7 I have just upgraded Rails to: 3.0.3 All I am trying to accomplish is to be able to render localhost.com:3000 in my browser of the GIT project i've already downloaded so I can work on it locally. I ran the command 'rails server' and was returned the message below:: Usage: rails new APP_PATH [options] Options: [--skip-gemfile] # Don't create a Gemfile -m, [--template=TEMPLATE] # Path to an application template (can be a filesystem path or URL) -d, [--database=DATABASE] # Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite3/frontbase/ibm_db) # Default: sqlite3 -O, [--skip-active-record] # Skip Active Record files -J, [--skip-prototype] # Skip Prototype files -T, [--skip-test-unit] # Skip Test::Unit files [--dev] # Setup the application with Gemfile pointing to your Rails checkout -r, [--ruby=PATH] # Path to the Ruby binary of your choice # Default: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -G, [--skip-git] # Skip Git ignores and keeps -b, [--builder=BUILDER] # Path to an application builder (can be a filesystem path or URL) [--edge] # Setup the application with Gemfile pointing to Rails repository Runtime options: -f, [--force] # Overwrite files that already exist -s, [--skip] # Skip files that already exist -p, [--pretend] # Run but do not make any changes -q, [--quiet] # Supress status output Rails options: -h, [--help] # Show this help message and quit -v, [--version] # Show Rails version number and quit Description: The 'rails new' command creates a new Rails application with a default directory structure and configuration at the path you specify. Example: rails new ~/Code/Ruby/weblog This generates a skeletal Rails installation in ~/Code/Ruby/weblog. See the README in the newly created application to get going.

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  • Login for webapp, needs to be availible for supportstaff

    - by Christian W
    I know the title is a little off, but it's hard to explain the problem in a short sentence. I am the administrator of a legacy webapp that lets users create surveys and distribute them to a group of people. We have two kinds of "users". 1. Authorized licenseholders which does all setup themselves. 2. Clients who just want to have a survey run, but still need a user (because the webapp has "User" as the top entity in a surveyenvironment.) Sometimes users in #1 want's us to do the setup for them (which we offer to do). This means that we have to login as them. This is also how we do support, we login as them and then follow them along, guiding them. Which brings me to my dilemma. Currently our security is below par. But this makes it simple for us to do support. We do want to increase our security, and one thing I have been considering is just doing the normal hashing to DB, however, we need to be able to login as a customer, and if they change their password without telling us, and the password is hashed in the db, we have no way of knowing it. So I was thinking of some kind of twoway encryption for the passwords. Either that or some kind of master password. Any suggestions? (The platform is classic ASP... I said it was legacy...)

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  • Can I output/flush data to screen while processing ajax page?

    - by Bee
    I need to display on my page a list of records pulled from a table. Ajax works fine (I query the database and put all the data inside a on the main page) but if I have lots of records (say 500+) it will hang until data is fully loaded, THEN it will be sent back to the page and correctly displayed. I would like to be able to display the records on the page while getting them, instead of being forced to wait until completion. I am trying with flush(); inside the remote (ajax) page but it still waits until full data is loaded. This is what I currently have inside the ajax page: At the very beginning: @apache_setenv('no-gzip', 1); @ini_set('zlib.output_compression', 0); @ini_set('implicit_flush', 1); for ($i = 0; $i < ob_get_level(); $i++) { ob_end_flush(); } ob_implicit_flush(1); Then whenever I have a echo call: ob_flush(); Now if I load the ajax page alone... it will list the records while reading them from the database. But if I call the same page via Ajax, it will hang and send all the data at once. Any idea? This is the function I use to get the ajax content ('id' is the target , 'url' refers to the ajax page that runs the database query to list the records): function ajax(id,url) { xmlhttp=new XMLHttpRequest(); xmlhttp.open("GET",url,false); xmlhttp.send(null); document.getElementById(id).innerHTML = parseScript(xmlhttp.responseText); }

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  • PHP Parse Error Help Needed

    - by adcmarti
    I am receiving this PHP parse error on the last line of this php file. What am I missing? Here is the last 15 lines or so. <div id="footer"> <br /> <p><b>Member Total:</b><?php echo $database->getNumMembers(); ?> <br>There are <?php echo $database->num_active_users; ?> registered members and <?php $database->num_active_guests; ?> guests viewing the site.<br><br> <?php include("include/view_active.php"); ?> </p> </div><!-- #footer --> <? } ?> </div><!-- #main --> <?php include("_footer.html"); ?> Any help would be appreciated. Thank you!

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  • Web Hosting URL Length Limit?

    - by Isaac Waller
    Hello, I am designing a web application which is a tie in to my iPhone application. It sends massively large URLs to the web server (15000 about.) I was using NearlyFreeSpeech.net, but they only support URLS up to 2000 characters. I was wondering if anybody knows of web hosting that will support really large URLs? Thanks, Isaac Edit: My program needs to open a picture in Safari. I could do this 2 ways: send it base64 encoded in the URL and just echo the query parameters. first POST it to the server in my application, then the server would send back a unique ID after storing the photo in a database, which I would append to a URL which I would open in Safari which retrieved the photo from the database and delete it from the database. You see, I am lazy, and I know Mobile Safari can support URI's up to 80 000 characters, so I think this is a OK way to do it. If there is something really wrong with this, please tell me. Edit: I ended up doing it the proper POST way. Thanks.

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  • Converting FoxPro Date type to SQL Server 2005 DateTime using SSIS

    - by Avrom
    Hi, When using SSIS in SQL Server 2005 to convert a FoxPro database to a SQL Server database, if the given FoxPro database has a date type, SSIS assumes it is an integer type. The only way to convert it to a dateTime type is to manually select this type. However, that is not practical to do for over 100 tables. Thus, I have been using a workaround in which I use DTS on SQL Server 2000 which converts it to a smallDateTime, then make a backup, then a restore into SQL Server 2005. This workaround is starting to be a little annoying. So, my question is: Is there anyway to setup SSIS so that whenever it encounters a date type to automatically assume it should be converted to a dateTime in SQL Server and apply that rule across the board? Update To be specific, if I use the import/export wizard in SSIS, I get the following error: Column information for the source and the destination data could not be retrieved, or the data types of source columns were not mapped correctly to those available on the destination provider. Followed by a list of a given table's date columns. If I manually set each one to a dateTime, it imports fine. But I do not wish to do this for a hundred tables.

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  • PHP syntax for referencing self with late static binding

    - by Chris
    When I learned PHP it was pretty much in procedural form, more recently I've been trying to adapt to the OOP way of doing things. Hoever the tutorials I've been following were produced before PHP 5.3 when late static binding was introduced. What I want to know is how do I reference self when calling a function from a parent class. For example these two methods were written for a User class which is a child of DatabaseObject. Right now they're sitting inside the User class, but, as they're used in other child classes of DatabaseObject I'd like to promote them to be included inside DatabaseObject. public static function find_all() { global $database; $result_set = self::find_by_sql("select * from ".self::$table_name); return $result_set; } and: protected function cleaned_attributes() { global $database; $clean_attributes = array(); foreach($this->attributes() as $key => $value) { $clean_attributes[$key] = $database->escape_value($value); } return $clean_attributes; } So I have three questions: 1) How do I change the self:: reference when I move it to the parent. Is it static:: or something similar? 2) When calling the function from my code do I call it in the same way, as a function of the child class eg User::find_all() or is there a change there also? 3) Is there anything else I need to know before I start chopping bits up?

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  • NPE with logging while launching webstart on jre7 update 40

    - by atulsm
    My application was running fine until I upgraded my jre to 7u40. When my application is initializing, it's doing Logger.getLogger("ClassName"), and I'm getting the following exception. java.lang.ExceptionInInitializerError at java.util.logging.Logger.demandLogger(Unknown Source) at java.util.logging.Logger.getLogger(Unknown Source) at com.company.Application.Applet.<clinit>(Unknown Source) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.sun.javaws.Launcher.executeApplication(Unknown Source) at com.sun.javaws.Launcher.executeMainClass(Unknown Source) at com.sun.javaws.Launcher.doLaunchApp(Unknown Source) at com.sun.javaws.Launcher.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.NullPointerException at java.util.logging.Logger.setParent(Unknown Source) at java.util.logging.LogManager$6.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.util.logging.LogManager.doSetParent(Unknown Source) at java.util.logging.LogManager.access$1100(Unknown Source) at java.util.logging.LogManager$LogNode.walkAndSetParent(Unknown Source) at java.util.logging.LogManager$LoggerContext.addLocalLogger(Unknown Source) at java.util.logging.LogManager$LoggerContext.addLocalLogger(Unknown Source) at java.util.logging.LogManager.addLogger(Unknown Source) at java.util.logging.LogManager$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.util.logging.LogManager.<clinit>(Unknown Source) The exception is coming from this line: private static Logger logger = Logger.getLogger(Applet.class.getName()); Could it be because of any sideeffects with fix http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8017174 ? A workaround is to open the java control center and enable logging. This is a concern since by default "Enable Logging" is unchecked. If I select "Enable Logging", the application starts fine.

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  • Oracle syntax - should we have to choose between the old and the new?

    - by Martin Milan
    Hi, I work on a code base in the region of about 1'000'000 lines of source, in a team of around eight developers. Our code is basically an application using an Oracle database, but the code has evolved over time (we have plenty of source code from the mid nineties in there!). A dispute has arisen amongst the team over the syntax that we are using for querying the Oracle database. At the moment, the overwhelming majority of our queries use the "old" Oracle Syntax for joins, meaning we have code that looks like this... Example of Inner Join select customers.*, orders.date, orders.value from customers, orders where customers.custid = orders.custid Example of Outer Join select customers.custid, contacts.ContactName, contacts.ContactTelNo from customers, contacts where customers.custid = contacts.custid(+) As new developers have joined the team, we have noticed that some of them seem to prefer using SQL-92 queries, like this: Example of Inner Join select customers.*, orders.date, orders.value from customers inner join orders on (customers.custid = orders.custid) Example of Outer Join select customers.custid, contacts.ContactName, contacts.ContactTelNo from customers left join contacts on (customers.custid = contacts.custid) Group A say that everyone should be using the the "old" syntax - we have lots of code in this format, and we ought to value consistency. We don't have time to go all the way through the code now rewriting database queries, and it wouldn't pay us if we had. They also point out that "this is the way we've always done it, and we're comfortable with it..." Group B however say that they agree that we don't have the time to go back and change existing queries, we really ought to be adopting the "new" syntax on code that we write from here on in. They say that developers only really look at a single query at a time, and that so long as developers know both syntax there is nothing to be gained from rigidly sticking to the old syntax, which might be deprecated at some point in the future. Without declaring with which group my loyalties lie, I am interested in hearing the opinions of impartial observers - so let the games commence! Martin. Ps. I've made this a community wiki so as not to be seen as just blatantly chasing after question points...

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  • Verizon SongID - How is it programmed?

    - by CheeseConQueso
    For anyone not familiar with Verizon's SongID program, it is a free application downloadable through Verizon's VCast network. It listens to a song for 10 seconds at any point during the song and then sends this data to some all-knowing algorithmic beast that chews it up and sends you back all the ID3 tags (artist, album, song, etc...) The first two parts and last part are straightforward, but what goes on during the processing after the recorded sound is sent? I figure it must take the sound file (what format?), parse it (how? with what?) for some key identifiers (what are these? regular attributes of wave functions? phase/shift/amplitude/etc), and check it against a database. Everything I find online about how this works is something generic like what I typed above. From audiotag.info This service is based on a sophisticated audio recognition algorithm combining advanced audio fingerprinting technology and a large songs' database. When you upload an audio file, it is being analyzed by an audio engine. During the analysis its audio “fingerprint” is extracted and identified by comparing it to the music database. At the completion of this recognition process, information about songs with their matching probabilities are displayed on screen.

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  • How do I exclude data from local table schema_migrations from being pushed to Heroku DB?

    - by Thierry Lam
    I was able to push my Ruby on Rails app with MySQL(local dev) to the Heroku server along with migrating my model with the command heroku rake db:migrate. I have also read the documentation on Database Import/Export. Is that doc referring to pushing actual data from my local dev DB to whichever Heroku's DB? Do I need to modify anything in the file database.yml to make it happen? I ran the following command: heroku db:push and I am getting the error: Sending data 2 tables, 3 records !!! Caught Server Exception | ETA: --:--:-- Taps Server Error: PGError ERROR: duplicate key value violates unique constraint "unique_schema_migrations" I have 2 tables, one I create for my app and the other schema_migrations. The total number of entries among the 2 tables is 3. I'm also printing the number of entries I have in the table I have created and it's showing 0. Any ideas what I might be missing or what I am doing wrong? EDIT: I figured out the above, Heroku's DB already have schema_migrations the moment I ran migrate. New question: Does anyone know how I can exclude data from a specific table from being pushed to Heroku DB. The table to exclude in this case will be schema_migrations. Not so good solution: I googled around and someone else was having the same issue. He suggested naming the schema_migrations table to zschema_migrations. In this way data from the other tables will be pushed properly until it fails on the last table. It's a pretty bad solution but will do for the time being. A better solution will be to use an existing Rails command which can reset a specific table from a database. I don't think Rake can do that.

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  • C# reference collection for storing reference types

    - by ivo s
    I like to implement a collection (something like List<T>) which would hold all my objects that I have created in the entire life span of my application as if its an array of pointers in C++. The idea is that when my process starts I can use a central factory to create all objects and then periodically validate/invalidate their state. Basically I want to make sure that my process only deals with valid instances and I don't re-fetch information I already fetched from the database. So all my objects will basically be in one place - my collection. A cool thing I can do with this is avoid database calls to get data from the database if I already got it (even if I updated it after retrieval its still up-to-date if of course some other process didn't update it but that a different concern). I don't want to be calling new Customer("James Thomas"); again if I initted James Thomas already sometime in the past. Currently I will end up with multiple copies of the same object across the appdomain - some out of sync other in sync and even though I deal with this using timestamp field on the MSSQL server I'd like to keep only one copy per customer in my appdomain (if possible process would be better). I can't use regular collections like List or ArrayList for example because I cannot pass parameters by their real local reference to the their existing Add() methods where I'm creating them using ref so that's not to good I think. So how can this be implemented/can it be implemented at all ? A 'linked list' type of class with all methods working with ref & out params is what I'm thinking now but it may get ugly pretty quickly. Is there another way to implement such collection like RefList<T>.Add(ref T obj)? So bottom line is: I don't want re-create an object if I've already created it before during the entire application life unless I decide to re-create it explicitly (maybe its out-of-date or something so I have to fetch it again from the db). Is there alternatives maybe ?

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  • Editing a .class file directly, playing around with opcodes

    - by echox
    Hi, today I just tried to play a little bit around with the opcodes in compiled java class file. After inserting iinc 1,1 the java virtual machine responds with: Exception in thread "main" java.lang.ClassFormatError: Truncated class file at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) at java.lang.ClassLoader.defineClass(ClassLoader.java:616) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) at java.net.URLClassLoader.access$000(URLClassLoader.java:58) at java.net.URLClassLoader$1.run(URLClassLoader.java:197) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) Could not find the main class: Test. Program will exit. This is my example source code: public class Test { public static void main(String[] args) { int i = 5; i++; i++; i++; System.out.println("Number: " + i + "\n"); } } The opcode for an increment is 0x84 + 2 bytes for operands. There's only one section in the resulting class file, which contains 0x84: [..] 8401 0184 0101 8401 01[..] So I would translate this as: iinc 1,1 iinc 1,1 iinc 1,1 corresponding to my i++; i++; i++; I then tried to append just 840101 to increment the variable once more, but that didn't work and resulted in the ClassFormatError. Is there anything like a checksum for the class file? I looked up the format of a classfile in http://java.sun.com/docs/books/jvms/second_edition/html/ClassFile.doc.html but could not find anything which points out to some kind of bytes_of_classfile or something. I also don't understand why the error is "Truncated Class File", because I did append something :-) I know its not a good idea to edit class files directly, but I'm just interested on the VM internals here.

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  • Merging datasets with 2 different time variables in SAS

    - by John
    Hye Guys, for those regularly browsing this site sorry for already another question (however I did solve my last question myself!) I have another problem with merging datasets, it seems that accounting for time in datasets is a real pain in the ass. I succesfully managed to merge on months in my previous datasets, however it seems I have a final dataset which only has quarter as a time count variable. So where all my normal databases have month 1- xxx as an indicator of time, this database had quarter as an indicator of time. I still want to add the variables of this last database, let's call it TVOL, into my WORK database. Quick summary QUARTER: Quarter 0 = JAN1996-MAR1996 Month: Month 0 = JAN1996 Example: TVOL TVOL _ Ticker ____ Quarter 1500 _ AA ________ -1 52546 _ BB ________ 15 Example: WORK BETA _ Ticker ____ Month 1.52 _ AA ________ 2 1.54__ BB _______ 3 Example: Merged: BETA ______ TVOL __ Ticker ____ Month 1.52 _______ 500 ___ AA _______ 2 I now want to merge this 2 tables using following relationship if the month is in quarter 1, the data of quarter 0 has to be used, so if i have an observation i nWORK with date 2FEB1996 the TVOL of quarter -1 has to be put behind this observation. Something like IF month = quarter i use data quarter i-1. Also, as TVOL is measured quarterly and I have to put in monthly I have to take the average, so (TVOL/3) should be added as a variable. Thanks!

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  • LINQ to XML contents of child records.

    - by Fossaw
    I have this LINQ to XML enquiry... var Records = from Item in XDoc.Root.Elements("Item") where (string)Item.Element("ItemNumber") == item.ID.ToString select Item; ... where ItemNumber is a reference number used in the XML, (originally written by this program but manually edited by "others"), and item.ID is the database version of the same thing. The query executes, and I can test for the number of entries in the result fine... if (Records.Count() < 1) ... you get the idea. I have established that there is only one record. Each Item has several child fields. I want to test the values of the child fields are reasonable before passing them on to the database update sub-system. The XML is produced by the program, but edited by users, so I need to really check what is coming back. So I tried... if (DB_English.ToString() != Records.Elements("English").ToString()) ... DB_English is from the database, but the XML in Records, does not contain the contents of that field, it contains... System.Xml.Linq.Extensions+<GetElements>d__29`1[System.Xml.Linq.XElement] ... so, how do I get the value of this element in the XML file? I need to check the field in the XML has not been altered, (the manual editors of this data file are not potentially 100% reliable).

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  • Storing Arbitrary Contact Information in Ruby on Rails

    - by Anthony Chivetta
    Hi, I am currently working on a Ruby on Rails app which will function in some ways like a site-specific social networking site. As part of this, each user on the site will have a profile where they can fill in their contact information (phone numbers, addresses, email addresses, employer, etc.). A simple solution to modeling this would be to have a database column per piece of information I allow users to enter. However, this seems arbitrary and limited. Further, to support allowing users to enter as many phone numbers as they would like requires the addition of another database table and joins. It seems to me that a better solution would be to serialize all the contact information entered by a user into a single field in their row. Since I will never be conditioning a SQL query on this information, such a solution wouldn't be any less efficient. Ideally, I would like to use a vCard as my serialization format. vCards are the standard solution to storing contact information across the web, and reusing tested solutions is a Good Thing. Alternative serialization formats would include simply marshaling a ruby hash, or YAML. Regardless of serialization format, supporting the reading and updating of this information in a rails-like way seems to be a major implementation challenge. So, here's the question: Has anyone seen this approach used in a rails application? Are there any rails plugins or gems that make such a system easy to implement? Ideally what I would like is an acts_as_vcard to add to my model object that would handle editing the vcard for me and saving it back to the database.

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  • struts datagrid problem - can't solve this problem

    - by shien-angel
    i am creating datagrid using the struts-layout. and i encountered this problem javax.servlet.ServletException: DispatchMapping[/monitor/datagridBL]???????????????????? at org.apache.struts.actions.DispatchAction.getParameter(DispatchAction.java:325) at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170) at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236) at jp.terasoluna.fw.web.struts.action.RequestProcessorEx.process(RequestProcessorEx.java:149) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414) at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at jp.co.anicom.fw.web.common.controller.RequestEncodeFilter.doFilter(RequestEncodeFilter.java:42) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at jp.co.anicom.fw.web.common.controller.SessionExpirationFilter.doFilter(SessionExpirationFilter.java:89) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3588) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2200) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2106) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1428) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) i have been looking for ways on how to solve this. would somebody help me please...

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