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  • If 'Architect' is a dirty word - what's the alternative; when not everyone can actually design a goo

    - by Andras Zoltan
    Now - I'm a developer first and foremost; but whenever I sit down to work on a big project with lots of interlinking components and areas, I will forward-plan my interfaces, base classes etc as best I can - putting on my Architect hat. For a few weeks I've been doing this for a huge project - designing whole swathes of interfaces etc for a business-wide platform that we're developing. The basic structure is a couple of big projects that consists of service and data interfaces, with some basic implementations of all of these. On their own, these assemblies are useless though, as they are simply intended intended as a scaffold on which to build a business-specific implementation (we have a lot of businesses). Therefore, the design of the core platform is absolutely crucial, since consumers of the system are not intended to know which implementation they are actually using. In the past it's not worked so well, but after a few proof-of-concepts and R&D projects this new platform is now growing nicely and is already proving itself. Then somebody else gets involved in the project - he's a TDD man who sees code-level architecture as an irrelevance and is definitely from the camp that 'architect' is a dirty word - I should add that our working relationship is very good despite this :) He's open about the fact that he can't architect in advance and obviously TDD really helps him because it allows him to evolve his systems over time. That I get, and totally understand; but it means that his coding style, basically, doesn't seem to be able to honour the architecture that I've been putting in place. Now don't get me wrong - he's an awesome coder; but the other day he needed to extend one of his components (an implementation of a core interface) to bring in an extra implementation-specific dependency; and in doing so he extended the core interface as well as his implementation (he uses ReSharper), thus breaking the independence of the whole interface. When I pointed out his error to him, he was dismayed. Being test-first, all that mattered to him was that he'd made his tests pass, and just said 'well, I need that dependency, so can't we put it in?'. Of course we could put it in, but I was frustrated that he couldn't see that refactoring the generic interface to incorporate an implementation-specific feature was just wrong! But it is all very Charlie Brown to him (you know the sound the adults make when they're talking to the children) - as far as he's concerned we don't need to worry about it because we can always refactor. The problem is, the culture of test-write-refactor is all very well and good - but not when you're dealing with a platform that is going to be shared out among so many projects that you could never get them all in one place to make the refactorings work. In my opinion, sometimes you actually have to think about what you're doing, and not just let nature take its course. Am I simply fulfilling the role of Architect as a dirty word here? I believe that architecture is important and should be thought about before code gets written; unless it's a particularly small project. But when you're working in a team of people who don't think that way, or even can't think that way how can you actually get this across? Is it a case of simply making the architecture off-limits to changes by other people? I don't want to start having bloody committees just to be able to grow the system; but equally I don't want to be the only one responsible for it all. Do you think the architect role is a waste of time? Is it at odds with TDD and other practises? Can this mix of different practises be made to work, or should I just be a lot less precious (and in so doing allow a generic platform become useless!)? Or do I just lay down the law? Any ideas/experiences/views gratefully received.

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  • Managing lots of callback recursion in Nodejs

    - by Maciek
    In Nodejs, there are virtually no blocking I/O operations. This means that almost all nodejs IO code involves many callbacks. This applies to reading and writing to/from databases, files, processes, etc. A typical example of this is the following: var useFile = function(filename,callback){ posix.stat(filename).addCallback(function (stats) { posix.open(filename, process.O_RDONLY, 0666).addCallback(function (fd) { posix.read(fd, stats.size, 0).addCallback(function(contents){ callback(contents); }); }); }); }; ... useFile("test.data",function(data){ // use data.. }); I am anticipating writing code that will make many IO operations, so I expect to be writing many callbacks. I'm quite comfortable with using callbacks, but I'm worried about all the recursion. Am I in danger of running into too much recursion and blowing through a stack somewhere? If I make thousands of individual writes to my key-value store with thousands of callbacks, will my program eventually crash? Am I misunderstanding or underestimating the impact? If not, is there a way to get around this while still using Nodejs' callback coding style?

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  • A business Case for Enterprise Python

    - by Srirangan
    Hi all, This will not be a "programming" question but more technology / platform related question. I'm trying to figure out whether Python can be a suitable Java alternative for enterprise / web applications. Which are the ideal cases where you would prefer to use Python instead of Java? How would a typical Python web application (databases/sessions/concurrency) perform as compared to a typical Java application? How do specific Python frameworks square up against Java based frameworks (Spring, SEAM, Grails etc.)? For businesses, switching from the Java infrastructure to a Python infrastructure .. is it too hard/expensive/resource intensive/not viable? Also shed some light on the business case for providing a Python + Google AppEngine based solution to the end customer. Will it be cost effective in an typical scenario? Sorry if I am asking too wide a question, I would have liked to keep it specific, but I need your help to evaluate Python as a whole from the perspectives of the programmers, service providing company and end business customer. For an SME, a Python/GoogleAppEngine based technology stack is a clear scalable and affordable platform. But what about a large MNC that already has a lot invested in Java. Thank you so much. I am researching this myself and will gladly share my conclusions here! Thank you, Srirangan

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  • How do you deal with denormalization / secondary indexes in database sharding?

    - by Continuation
    Say I have a "message" table with 2 secondary indexes: "recipient_id" "sender_id" I want to shard the "message" table by "recipient_id". That way to retrieve all messages sent to a certain recipient I only need to query one shard. But at the same time, I want to be able to make a query that ask for all messages sent by a certain sender. Now I don't want to send that query to every single shard of the "message" table. One way to do this is to duplicate the data and have a "message_by_sender" table sharded by "sender_id". The problem with that approach is that every time a message has been sent, I need to insert the message into both "message" and "message_by_sender" tables. But what if after inserting into "message" the insertion into "message_by_sender" fail? In that case the message exists in "message" but not in "message_by_sender". How do I make sure that if a message exists in "message" then it also exists in "message_by_sender" without resorting to 2 phase commit? This must be a very common issue for anyone who shards their databases. How do you deal woth it?

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  • sql exception when transferring project from usb to c:\

    - by jello
    I'm working on a C# windows program with Visual Studio 2008. Usually, I work from school, directly on my usb drive. But when I copy the folder on my hard drive at home, an sql exception is unhandled whenever I try to write to the database. it is unhandled at the conn.Open(); line. here's the exception unhandled Database 'L:\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf' already exists. Choose a different database name. Cannot attach the file 'C:\Documents and Settings\Administrator\My Documents\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf' as database 'PatientMonitoringDatabase'. it's weird, because my connection string says |DataDirectory|, so it should work on any drive... here's my connection string: string connStr = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\PatientMonitoringDatabase.mdf; " + "Initial Catalog=PatientMonitoringDatabase; " + "Integrated Security=True"; Someone told me to: Connect to localhost with SQL Server Management Studio Express, and remove/detach the existing PatientMonitoringDatabase database. Whether it's a persistent database or only active within a running application, you can't have 2 databases with the same name at the same time attached to a SQL Server instance. So I did that, and now it gives me: Directory lookup for the file "C:\Documents and Settings\Administrator\My Documents\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf" failed with the operating system error 5(Access is denied.). Cannot attach the file 'C:\Documents and Settings\Administrator\My Documents\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf' as database 'PatientMonitoringDatabase' I checked the files' properties, and I have allow for everyone. Does anyone know what's going on here?

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  • Why use SQL database?

    - by martinthenext
    I'm not quite sure stackoverflow is a place for such a general question, but let's give it a try. Being exposed to the need of storing application data somewhere, I've always used MySQL or sqlite, just because it's always done like that. As it seems like the whole world is using these databases, most of all software products, frameworks, etc. It is rather hard for a beginning developer like me to ask a question - why? Ok, say we have some object-oriented logic in our application, and objects are related to each other somehow. We need to map this logic to the storage logic, so we need relations between database objects too. This leads us to using relational database and I'm ok with that - to put it simple, our database rows sometimes will need to have references to other tables' rows. But why do use SQL language for interaction with such a database? SQL query is a text message. I can understand this is cool for actually understanding what it does, but isn't it silly to use text table and column names for a part of application that no one ever seen after deploynment? If you had to write a data storage from scratch, you would have never used this kind of solution. Personally, I would have used some 'compiled db query' bytecode, that would be assembled once inside a client application and passed to the database. And it surely would name tables and colons by id numbers, not ascii-strings. In the case of changes in table structure those byte queries could be recompiled according to new db schema, stored in XML or something like that. What are the problems of my idea? Is there any reason for me not to write it myself and to use SQL database instead?

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  • Creating Lotus Notes documents with specific created/modified/last accessed dates for testing

    - by Xolstice
    I'm currently writing an application that moves Notes documents between databases based on the amount of days that have elapsed from the creation/modified/last accessed dates. I would just like to get ideas on a simple and convenient way to create documents with specific dates, without having to change the time on the Domino server, so that I could test out my application. The best way I found so far was to create a local replica and change the system clock to the date I want. Unfortunately there are problems associated with this method. It does not work on the modified date - I'm not sure how it is getting the modified date information when the location is set to Island (Disconnected) - and it also changes the modified and last accessed dates when the documents are replicated to the server replica. Someone suggested trying to create a DXL of the document, modify the date time in the DXL file, then import it back into the database as a Notes document; but that does not work. It just takes on the date-time that it was created. Can anyone offer any other suggestions?

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  • Execute SQL on CSV files via JDBC

    - by Markos Fragkakis
    Dear all, I need to apply an SQL query to CSV files (comma-separated text files). My SQL is predefined from another tool, and is not eligible to change. It may contain embedded selects and table aliases in the FROM part. For my task I have found two open-source (this is a project requirement) libraries that provide JDBC drivers: CsvJdbc XlSQL JBoss Teiid Create an Apache Derby DB, load all CSVs as tables and execute the query. These are the problems I encountered: it does not accept the syntax of the SQL (it uses internal selects and table aliases). Furthermore, it has not been maintained since 2004. I could not get it to work, as it has as dependency a SAX Parser that causes exception when parsing other documents. Similarly, no change since 2004. Have not checked if it supports the syntax, but seems like an overhead. It needs several entities defines (Virtual Databases, Bindings). From the mailing list they told me that last release supports runtime creation of required objects. Has anyone used it for such simple task (normally it can connect to several types of data, like CSV, XML or other DBS and create a virtual, unified one)? Can this even be done easily? From the 4 things I considered/tried, only 3 and 4 seem to me viable. Any advice on these, or any other way in which I can query my CSV files? Cheers

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  • What's the largest (most complex) PHP algorithm ever implemented in a single monolithic PHP script?

    - by Alex R
    I'm working on a tool which converts PHP code to Scala. As one of the finishing touches, I'm in need of a really good (er, somewhat biased) benchmark. By dumb luck my first benchmark attempt was with some code which uses bcmath extensively, which unfortunately is 1000x slower in Java, making the Scala code 22x slower overall than the original PHP. So I'm looking for some meaningful PHP benchmark with the following characteristics: The source needs to be in a single file. I need it to be simple to setup - no databases, hard-to-find input files, etc. Simple text input and output preferred. It should not use features that are slow in Java (BigInteger, trigonometric functions, etc). It should not use exoteric or dynamic PHP functions (e.g. no "eval" or "variable vars"). It should not over-rely on built-in libraries, e.g. MD5, crypt, etc. It should not be I/O bound. A CPU-bound memory-hungry algorithm is preferred. Basically, intensive OO operations, integer and string manipulation, recursion, etc would be great. Thanks

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  • How to avoid chaotic ASP.NET web application deployment?

    - by emzero
    Ok, so here's the thing. I'm developing an existing (it started being an ASP classic app, so you can imagine :P) web application under ASP.NET 4.0 and SQLServer 2005. We are 4 developers using local instances of SQL Server 2005 Express, having the source-code and the Visual Studio database project This webapp has several "universes" (that's how we call it). Every universe has its own database (currently on the same server) but they all share the same schema (tables, sprocs, etc) and the same source/site code. So manually deploying is really annoying, because I have to deploy the source code and then run the sql scripts manually on each database. I know that manual deploying can cause problems, so I'm looking for a way of automating it. We've recently created a Visual Studio Database Project to manage the schema and generate the diff-schema scripts with different targets. I don't have idea how to put the pieces together I would like to: Have a way to make a "sync" deploy to a target server (thanksfully I have full RDC access to the servers so I can install things if required). With "sync" deploy I mean that I don't want to fully deploy the whole application, because it has lots of files and I just want to deploy those new or changed. Generate diff-sql update scripts for every database target and combine it to just 1 script. For this I should have some list of the databases names somewhere. Copy the site files and executing the generated sql script in an easy and automated way. I've read about MSBuild, MS WebDeploy, NAnt, etc. But I don't really know where to start and I really want to get rid of this manual deploy. If there is a better and easier way of doing it than what I enumerated, I'll be pleased to read your option. I know this is not a very specific question but I've googled a lot about it and it seems I cannot figure out how to do it. I've never used any automation tool to deploy. Any help will be really appreciated, Thank you all, Regards

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  • Which PHP library I should choose to work with CouchDB?

    - by Guss
    I want to try playing with CouchDB for a new project I'm writing (as a hobby, not part of my job). I'm well versed in PHP, but I haven't programmed with CouchDB at all, and also I have little experience with non-SQL databases. From looking at CouchDB's "Getting Started with PHP" document they recommend using a third-party library or writing your own client using their RESTful HTTP API. I think I'd rather not mess with writing protocol implementations myself at this point, but what is your experience with writing PHP to work with CouchDB? I haven't tested any of the alternatives yet, but I looked at: PHPillow : I'm interested in the way they implement ORM. I wasn't planning to do ORM, but my problem domain probably map well to that method. PHP Object Freezer: seems like a poor man's ORM - I can use it to implement an actual ORM, or just as an easy store/retrieve document API but it seems too primitive. PHP-on-Couch : Also a bit simple, but they have an interesting API for views and from the documentation it looks usable enough. PHP CouchDB Extension : From the listed options this looks like it has the best chance of making it into the PHP mainline itself, and also has the most complete API. Any opinion one wish to share on each library is welcome.

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  • Pros/Cons of MySQL vs Postgresql for production Ruby on Rails environment?

    - by cakeforcerberus
    I will soon be switching from sqlite3 to either postgres or mysql. What should I consider when making this decision? Is mysql more suited for Rails than postgres in some areas and/or vice versa? Or, as I somewhat suspect, does it not really matter either way? Another factor that might play into my decision is the availability of tools to data pump my test data from the sqlite3 db to my new one. Is there anything that ActiveRecord provides natively to do this or any decent plugins/gems to help with this task? BONUS: How do I pronounce "Postgresql" and sound like I know what I'm talking about? :) Thanks Greg Smith for providing the following link that shows the most common pronunciations: http://www.postgresql.org/community/survey.33 UPDATE: Reference this question for more: http://stackoverflow.com/questions/110927/do-you-recommend-postgresql-over-mysql FYI: I ended up using MySQL. There is a neat plugin called yamldb that really saved me some time with the data transfer from my sqlite db to my new mysql one. Instructions on how to install and use it can be found here: http://accidentaltechnologist.com/ruby/change-databases-in-rails-with-yamldb/ Thanks Tom

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  • iPhone and Core Data: how to retain user-entered data between updates?

    - by Shaggy Frog
    Consider an iPhone application that is a catalogue of animals. The application should allow the user to add custom information for each animal -- let's say a rating (on a scale of 1 to 5), as well as some notes they can enter in about the animal. However, the user won't be able to modify the animal data itself. Assume that when the application gets updated, it should be easy for the (static) catalogue part to change, but we'd like the (dynamic) custom user information part to be retained between updates, so the user doesn't lose any of their custom information. We'd probably want to use Core Data to build this app. Let's also say that we have a previous process already in place to read in animal data to pre-populate the backing (SQLite) store that Core Data uses. We can embed this database file into the application bundle itself, since it doesn't get modified. When a user downloads an update to the application, the new version will include the latest (static) animal catalogue database, so we don't ever have to worry about it being out of date. But, now the tricky part: how do we store the (dynamic) user custom data in a sound manner? My first thought is that the (dynamic) database should be stored in the Documents directory for the app, so application updates don't clobber the existing data. Am I correct? My second thought is that since the (dynamic) user custom data database is not in the same store as the (static) animal catalogue, we can't naively make a relationship between the Rating and the Notes entities (in one database) and the Animal entity (in the other database). In this case, I would imagine one solution would be to have an "animalName" string property in the Rating/Notes entity, and match it up at runtime. Is this the best way to do it, or is there a way to "sync" two different databases in Core Data?

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  • Is there a PHP benchmark that meets these specific criteria? [closed]

    - by Alex R
    I'm working on a tool which converts PHP code to Scala. As one of the finishing touches, I'm in need of a really good (er, somewhat biased) benchmark. By dumb luck my first benchmark attempt was with some code which uses bcmath extensively, which unfortunately is 1000x slower in Java, making the Scala code 22x slower overall than the original PHP. So I'm looking for some meaningful PHP benchmark with the following characteristics: The PHP source needs to be in a single file. It should solve a real-world problem. No silly looping over empty methods etc. I need it to be simple to setup - no databases, hard-to-find input files, etc. Simple text input and output preferred. It should not use features that are slow in Java (BigInteger, trigonometric functions, etc). It should not use exoteric or dynamic PHP functions (e.g. no "eval" or "variable vars"). It should not over-rely on built-in libraries, e.g. MD5, crypt, etc. It should not be I/O bound. A CPU-bound memory-hungry algorithm is preferred. Basically, intensive OO operations, integer and string manipulation, recursion, etc would be great. Thanks

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  • Running SQLite 3 in MicroApache

    - by Alien426
    I'm running MicroApache (http://microapache.amadis.sytes.net) on Windows XP and would like to use SQLite 3 databases. The PHP version is 5.2.9-2. My MicroApache version has SQLite 2 support through 2 lines in the php.ini: extension=php_pdo.dll extension=php_sqlite.dll I test whether the extension works in 3 ways: 1. phpinfo() 2. extension_loaded() and get_loaded_extensions() 3. using sample code that var_dump()s the constant SQLITE3_NUM (should be the integer 2) and tries to create a database (error: class 'SQLite3' does not exist) Things I have tried (if I can remember them all): 1. copied php_sqlite3.dll from a full installation of PHP and added "extension=php_sqlite3.dll" to php.ini - error "Procedure entry point gc_remove_zval_from_buffer was not found in php5ts.dll" 2. compressed the DLL with UPX (like the other DLLs of MicroApache seem to be) - does not display an error on start, nor in the log file, but does not work 3. tried various things with php.ini - created a section "[sqlite3]" - prefixed "sqlite3." to "extension_dir=." and "extension=php_sqlite3.dll" - ... 4. tried to use PDO, it says it 'could not find driver' Who can help me get SQLite 3 to work?

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  • Getting content from PHP: Trouble with POST and query.

    - by vgm64
    Apologies for my longest question on SO ever. I'm trying to interface with a php frontend for a mysql database in ROOT (a CERN framework in C++ for high energy physics analysis). To start off with, I tried to get this php interface to play nice with wget and curl first because I'm more familiar with them. The following command works: wget --post-data "hostname=localhost:3306&un=joeuser&pw=psswd&myquery=show_spazio_databases;" http://some.host.edu/log/log_query_matlab.php The results are: database1 database2 That's good. If I leave out the --post-data then I get the result: Warning: mysql_connect() [function.mysql-connect]: Access denied for user 'admin'@'localhost' (using password: NO) in /log/log_query_matlab.php on line 6 i'm dead! Access denied for user 'admin'@'localhost' (using password: NO) Warning: mysql_query() [function.mysql-query]: Access denied for user 'admin'@'localhost' (using password: NO) in /log/log_query_matlab.php on line 29 Warning: mysql_query() [function.mysql-query]: A link to the server could not be established in /log/log_query_matlab.php on line 29 I have access to the php script (read only), but the error itself isn't too important. What matters it that using ROOT, I use a function called as socket.SendRaw(message, message.Length()) (socket is a TSocket) and this gives me the same "error" as wget without the post data switch if my "message" is "POST http://some.host.edu/log/log_query_matlab.php?hostname=localhost:3306&un=joeuser&pw=psswd&myquery=show_spazio_databases" This may be in vain, but does someone knows a way I should format the "message" that includes something that is equivalent to the --post-data switch. Or, is there a standard way to format POST requests in a single line (I've seen multi-line stuff. Is that right?) Sorry I'm clueless! PS. The mysql query is show databases but the space has been replaced with _spazio_, Italian for space. The author of the db and php interface requires it (and various replacements for symbols), but has anyone seen this before? Trying to troubleshoot that was terrible!

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  • Splitting MS Access Database - Front End Part Location

    - by kristof
    One of the best practices as specified by Microsoft for Access Development is splitting Access application into 2 parts; Front End that hold all the object except tables and the Back End that holds the tables. The msdn page links there to the article Splitting Microsoft Access Databases to Improve Performance and Simplify Maintainability that describes the process in details. It is recommended that in multi user environment the Back End is stored on the server/shared folder while the Front End is distributed to each user. That implies that each time there are any changes made to the front end they need to be deployed to every user machine. My question is: Assuming that the users themselves do not have rights to modify the Front End part of the application what would be the drawbacks/dangers of leaving this on the server as well next to the Back End copy? I can see the performance issues here, but are there any dangers here like possible corruptions etc? Thank you EDIT Just to clarify, the scenario specified in question assumes one Front End stored on the server and shared by users. I understand that the recommendation is to have FE deployed to each user machine, but my question is more about what are the dangers if that is not done. E.g. when you are given an existing solution that uses the approach of both FE and BE on the server. Assuming the the performance is acceptable and the customer is reluctant to change the approach would you still push the change? And why exactly? For example the danger of possible data corruption would definitely be the strong enough argument, but is that the case? It is a part of follow up of my previous question From SQL Server to MS Access 2007

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  • Regressing panel data in SAS.

    - by John
    Hey Guys, thanks to your help I succesfully managed all my databases! I am now looking at a panel data set on which I have to regress. Since I only started my Phd this semester together with the econometrics courses I am still new to many statistic applications and regression methods. I want to do a simple regression as in Y = x1 x2 x3 etc, now I already browsed through some literature and found that for panel data it's common to do a fixed effects regression. Also, my Y variable only has positive values so I was thinking in the direction of a Tobit model? I'm doing some research concerning the coverage of analysts in the financial business. My independent variable is the coverage of analysts on a certain firm, so per observation i have 1 analyst and 1 firm, together with different characteristics(market cap and betas etc) of the firm. All this data is monthly. As coverage cannot become negative (only 0) I was thinking of a Tobit model? Do you guys have any ideas what would be a good regression method? Or have some good sources (e books, written books, through university I have access to almost anything concerning my field of work) of information (cause I do have to learn these things for future research)? Thanks!

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  • Combining data sets without losing observations in SAS

    - by John
    Hye guys, I know, another post another problem :D :(. I took a screenshot to easily explain my problem. http://i39.tinypic.com/rhms0h.jpg As you can see I want to merge two tables (again), the Base & Analyst table. What I want to achieve is displayed in the right bottom corner table. I’m calculating the number of total analysts and female analysts for each month in the analyst table. In the base table I have different observations for one company (here company Alcoa with ticker AA). When I use the following command: data want; merge base analyst; by month ; run; I get the right up corner problem. My observations in the main table are being narrowed down to only 4 observations (for each different year one observation, 2001, 2002, 2005, 2006). What I want is that the observations are not reduced but that for every year the same data is being placed as shown in the right bottom corner. What am I missing in my merge command? In both tables I have month as a time count variable ( the observations in my base table are monthly) on which I need to merge. For clarity I added 2 screenshots of my real databases in SAS. The base table: http://i42.tinypic.com/dr5jky.jpg The analyst table: http://i40.tinypic.com/eqpmqq.jpg Here is what my merged table looks like: http://i43.tinypic.com/116i62s.jpg You can clearly see that the merged table only has four observations left for AA (one for each unique year) instead of the original 8. Anyone an idea to solve this?

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  • exec problem in sql 2005

    - by IordanTanev
    Hi, i have the situation where i have two databases whith same structure. The first have some data in its datatables. I need to create a script that will transfer the data from the first database to the second. I have created this script. DECLARE @table_name nvarchar(MAX), @query nvarchar(MAX) DECLARE @table_cursor CURSOR SET @table_cursor = CURSOR FAST_FORWARD FOR Select TABLE_NAME FROM INFORMATION_SCHEMA.TABLES OPEN @table_cursor FETCH NEXT FROM @table_cursor INTO @table_name WHILE @@FETCH_STATUS = 0 BEGIN SET @query = 'INSERT INTO ' + @table_name + ' SELECT * FROM MyDataBase.dbo.' + @table_name print @query exec @query FETCH NEXT FROM @table_cursor INTO @table_name END CLOSE @table_cursor DEALLOCATE @table_cursor The problem is that when i run th script the "print @query" statement prints statement like this INSERT INTO table SELECT * FROM MyDataBase.dbo.table When i copy this and run it from Management studio it works fine. But when the script trys to run it with exec i get this error Msg 911, Level 16, State 1, Line 21 Could not locate entry in sysdatabases for database 'INSERT INTO table SELECT * FROM MPDEV090314'. No entry found with that name. Make sure that the name is entered correctly. Hope someone can tell me whot is wront with this. Best Regards, Iordan Tanev

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  • Is it just me? I find LINQ to XML to be sort of cumbersome, compared to XPath.

    - by Cheeso
    I am a C# programmer, so I don't get to take advantage of the cool XML syntax in VB. Dim itemList1 = From item In rss.<rss>.<channel>.<item> _ Where item.<description>.Value.Contains("LINQ") Or _ item.<title>.Value.Contains("LINQ") Using C#, I find XPath to be easier to think about, easier to code, easier to understand, than performing a multi-nested select using LINQ to XML. Look at this syntax, it looks like Greek swearing: var waypoints = from waypoint in gpxDoc.Descendants(gpx + "wpt") select new { Latitude = waypoint.Attribute("lat").Value, Longitude = waypoint.Attribute("lon").Value, Elevation = waypoint.Element(gpx + "ele") != null ? waypoint.Element(gpx + "ele").Value : null, Name = waypoint.Element(gpx + "name") != null ? waypoint.Element(gpx + "name").Value : null, Dt = waypoint.Element(gpx + "cmt") != null ? waypoint.Element(gpx + "cmt").Value : null }; All the casting, the heavy syntax, the possibility for NullPointerExceptions. None of this happens with XPath. I like LINQ in general, and I use it on object collections and databases, but my first go-round with querying XML led me right back to XPath. Is it just me? Am I missing something? EDIT: someone voted to close this as "not a real question". But it is a real question, stated clearly. The question is: Am I misunderstanding something with LINQ to XML?

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  • Rails: constraint violation on create but not on update

    - by justinbach
    Note: This is a "railsier" (and more succinct) version of this question, which was getting a little long. I'm getting Rails behavior on a production server that I can't replicate on the development server. The codebases are identical save for credentials and caching settings, and both are powered by Oracle 10g databases with identical schema (but different data). My Rails application contains a user model, which has_one registration; registration in turn has_and_belongs_to_many company_ownerships through a registration_ownerships table. Upon registering, users fill out data pertinent to all three models, including a series of checkboxes indicating what registration_ownerships might apply to their account. On the dev server, the registration process is seamless, no matter what data is entered. On production, however, if users check off any of the company ownership fields before submitting their registration, Oracle complains about a constraint violation on the primary key of the company_ownerships table (which is a two-field key based on company_ownership_id and registration_id) and users get the standard Rails 500 error screen. In every case, I've verified that no conflicting record on these two fields exists in the production database, so I don't know why the constraint is getting violated. To further confuse things, if a user registers without listing any ownerships and later goes back and modifies their account to reflect ownership data (which is done through the same interface), the application happily complies with their request and Oracle is well-behaved (this is both on production and dev). I've spent the past couple days trying to figure out what might be causing this problem and am reaching the end of my wits. Any advice would be greatly appreciated!

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  • Advice on designing and building distributed application to track vehicles

    - by dario-g
    I'm working on application for tracking vehicles. There will be about 10k or more vehicles. Each will be sending ~250bytes in each minute. Data contains gps location and everything from CAN Bus (every data that we can read from vehicle computer and dashboard). Data are sent by GSM/GPRS (using UDP protocol). Estimated rows with this data per day is ~2000k. I see there 3 main blocks. 1. Multithreaded Socket Server (MSS) - I have it. MSS stores received data to the queue (using NServiceBus). 2. Rule Processor Server (RPS) - this is core of this system. This block is responsible for parsing received data, storing in the database, processing rules, sending messages to Notifier Server (this will be sending e-mails/sms texts). Rule example. As I said between received bytes there will be information about current speed. When speed will be above 120 then: show alert in web application for specified users, send e-mail, send sms text. (There can be more than one instance of RPS). 3. Web application - allows reporting and defining rules by users, monitoring alerts, etc. I'm looking for advice how to design communication between RPS and Web application. Some questions: - Should Web application and RPS have separated databases or one central database will be enough? I have one domain model in web application. If there will be one central database then can I use the same model (objects) on RPS? So, how to send changed rules to RPS? I try to decouple this blocks as much as possible. I'm planning to create different instance of application for each client (each client will have separated database). One client will be have 10k vehicles, others only 100 vehicles.

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  • Updating nullability of columns in SQL 2008

    - by Shaul
    I have a very wide table, containing lots and lots of bit fields. These bit fields were originally set up as nullable. Now we've just made a decision that it doesn't make sense to have them nullable; the value is either Yes or No, default No. In other words, the schema should change from: create table MyTable( ID bigint not null, Name varchar(100) not null, BitField1 bit null, BitField2 bit null, ... BitFieldN bit null ) to create table MyTable( ID bigint not null, Name varchar(100) not null, BitField1 bit not null, BitField2 bit not null, ... BitFieldN bit not null ) alter table MyTable add constraint DF_BitField1 default 0 for BitField1 alter table MyTable add constraint DF_BitField2 default 0 for BitField2 alter table MyTable add constraint DF_BitField3 default 0 for BitField3 So I've just gone in through the SQL Management Studio, updating all these fields to non-nullable, default value 0. And guess what - when I try to update it, SQL Mgmt studio internally recreates the table and then tries to reinsert all the data into the new table... including the null values! Which of course generates an error, because it's explicitly trying to insert a null value into a non-nullable column. Aaargh! Obviously I could run N update statements of the form: update MyTable set BitField1 = 0 where BitField1 is null update MyTable set BitField2 = 0 where BitField2 is null but as I said before, there are n fields out there, and what's more, this change has to propagate out to several identical databases. Very painful to implement manually. Is there any way to make the table modification just ignore the null values and allow the default rule to kick in when you attempt to insert a null value?

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  • Ruby script/console and Ruby script/server using two different DBs?

    - by aronchick
    Has anyone seen where script/console and script/server load two different databases (though both report using the same)? Here's the first output $ script/server => Booting WEBrick => Rails 2.3.5 application starting on http://0.0.0.0:3000 => Call with -d to detach => Ctrl-C to shutdown server [2010-03-21 15:54:05] INFO WEBrick 1.3.1 [2010-03-21 15:54:05] INFO ruby 1.8.7 (2010-01-10) [i386-mingw32] [2010-03-21 15:54:05] INFO WEBrick::HTTPServer#start: pid=7148 port=3000 No errors. I then run my standard code for entering a form - no problems. Checking the Dev Database (.yml at bottom): mysql> select * from books; [...] | 712 | Book | Book Name | 2010-03-21 22:29:22 | 2010-03-21 22:29:22 | [...] 712 rows in set (0.00 sec) The code CLEARLY saved it seconds ago And now here's the output of script/console: $ script/console Loading development environment (Rails 2.3.5) >> Books.all => [] Nothing. Further, upon further inspection, it's using the production database, but I can't figure out why. Any thoughts here? All consoles have been closed and reopened. UPDATE: Requested .yml file (can't see how it'd be helpful (user name and password are all the same for each)) - development: adapter: mysql database: BooksDBdev username: <user name> password: <long string> timeout: 5000 # Warning: The database defined as "test" will be erased and # re-generated from your development database when you run "rake". # Do not set this db to the same as development or production. test: adapter: mysql database: BooksDBtest username: <user name> password: <long string> timeout: 5000 production: adapter: mysql database: BooksDB username: <user name> password: <long string> timeout: 5000

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