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  • Several Small, Specific, MySQL Query Cache Questions

    - by Robbie
    I've look all over the web and in the questions asked here about MySQL caching and most of them seem very non-specific about a couple of questions that I have about performance and MySQL query caching. Specifically I want answers to these questions, assume for all questions that I have the query cache enabled and it is of type 2, or "DEMAND": Is the query cache per table, per database, or per server? Meaning if I have the cache size set to X and have T tables and D databases will I be caching TX, DX, or X amount of data? If I have table T1 which I regularly use the SQL_CACHE hint on for SELECT queries and table T2 which I never do, when I query T2 with a SELECT query will it check through the cache first before performing the query? *Note: I don't want to use the SQL_NO_CACHE for all T2 queries.* Assume the same situation as in question 2. If I alter (INSERT, DELETE) table T2 will any processing be done on the cache? For answers to 2 and 3, is this processing time negligible if T2 is constantly being altered and is the target of a majority of my SELECT queries?

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  • What type of webapp is the sweet spot for Scala's Lift framework?

    - by ajay
    What kind of applications are the sweet spot for Scala's lift web framework. My requirements: Ease of development and maintainability Ready for production purposes. i.e. good active online community, regular patches and updates for security and performance fixes etc. Framework should survive a few years. I don't want to write a app in a framework for which no updates/patches are available after 1 year. Has good UI templating engines Interoperation with Java (Scala satisfies this arleady. Just mentioning here for completeness sake) Good component oriented development. Time required to develop should be proportion to the complexity of web application. Should not be totally configuration based. I hate it when code gets automatically generated for me and does all sorts of magic under the hood. That is a debugging nightmare. Amount of Lift knowledge required to develop a webapp should be proportional to the complexity of the web application. i.e I should't have to spend 10+ hours learning Lift just to develop a simple TODO application. (I have knowledge of Databases, Scala) Does Lift satisfy these requirements?

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  • Linq to SQL Problem System.Data.Linq.IdentityManager.StandardIdentityManager.MultiKeyManager

    - by luckyluke
    I have a really tricky thing going up here. My project has around 100 tables and they are all mapped by LINQ. Everything works fine in a dev and test environment. These enviroments are MS Win 2008 r2 servers with SQL 2008 sp1 databases. IIS and SQL are on a different machines. Now on production enviroment which is MS Win 2003 x64 web farm + geoclustered SQL 2008 IT DOES not work. All I get is the exception System.IndexOutOfRangeException: Index was outside the bounds of the array. at System.Data.Linq.IdentityManager.StandardIdentityManager.MultiKeyManager3.TryCreateKeyFr>om Values(Object[] values, MultiKey& k) at System.Data.Linq.IdentityManager.StandardIdentityManager.IdentityCache2.Find(Object[] keyValues) at System.Data.Linq.ChangeProcessor.GetOtherItem(MetaAssociation assoc, Object instance) at System.Data.Linq.ChangeProcessor.BuildEdgeMaps() at System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at ERS.IIMP.Services.ExposuresSrv.Update(Int32 ExpID, Int32 AssID) Services\ExposuresSrv.cs` My question is What the hell. They have precisely the same DBML, the DB has exactly THE SAME structure (when I get the DB from prod to TEST and mount it eveything works just great), the binaries on the WEB Server are the same. I seriously do not know what to do.... Did anyone found that Linq works on one env and does not on the second?? I mam really lost here. I really hope You can help me:)

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  • The "first past the post election" query problem

    - by MPelletier
    This problem may seem like school work, but it isn't. At best it is self-imposed school work. I encourage any teachers to take is as an example if they wish. "First past the post" elections are single-round, meaning that whoever gets the most votes win, no second rounds. Suppose a table for an election. CREATE TABLE ElectionResults ( DistrictHnd INTEGER NOT NULL, PartyHnd INTEGER NOT NULL, CandidateName VARCHAR2(100) NOT NULL, TotalVotes INTEGER NOT NULL, PRIMARY KEY DistrictHnd, PartyHnd); The table has two foreign keys: DistrictHnd points to a District table (lists all the different electoral districts) and PartyHnd points to a Party table (lists all the different political parties). I won't bother with other tables here, joining them is trivial. This is just a wee bit of context. The question: What SQL query will return a table listing the DistrictHnd, PartyHnd, CandidateName and TotalVotes of the winners (max votes) in each District? This does not suppose any particular database system. If you wish to stick to a particular implementation of SQL, go the way of SQLite and MySQL. If you can devise a better schema (or an easier one), that is acceptable too. Criteria: simplicity, portability to other databases.

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  • h2 (embedded mode ) database files problem

    - by aeter
    There is a h2-database file in my src directory (Java, Eclipse): h2test.db The problem: starting the h2.jar from the command line (and thus the h2 browser interface on port 8082), I have created 2 tables, 'test1' and 'test2' in h2test.db and I have put some data in them; when trying to access them from java code (JDBC), it throws me "table not found exception". A "show tables" from the java code shows a resultset with 0 rows. Also, when creating a new table ('newtest') from the java code (CREATE TABLE ... etc), I cannot see it when starting the h2.jar browser interface afterwards; just the other two tables ('test1' and 'test2') are shown (but then the newly created table 'newtest' is accessible from the java code). I'm inexperienced with embedded databases; I believe I'm doing something fundamentally wrong here. My assumption is, that I'm accessing the same file - once from the java app, and once from the h2 console-browser interface. I cannot seem to understand it, what am I doing wrong here?

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  • Parsing a blackberry .ipd file

    - by galaxywatcher
    I recently lost my Blackberry. When I discovered it was gone very shortly afterwards and called it, the sim card had already been removed. I ain't seeing that Blackberry again. Ok. I am out $300, but at least my data is backed up. I had an older working Blackberry fortunately and I got a new sim card and proceeded to restore my data using Blackberry Desktop Manager. 7000+ emails, hundreds of autotext entries, sms messages, calendar events, all backing up. Looking good. Lo and behold! My Address Book contacts refuse to back up? I try advanced, and it is greyed out as an option to restore. Far more frustrating than losing my bberry in the first place is wrangling with software that defies human logic. Ok, now I guess I will have to enter all 327 names by hand. That is, if I can read the .ipd file. I have tried the free version of ABC Amber Blackberry editor, but when I open the .ipd file, the contacts just do not show up. I am beginning to feel like the gods are conspiring against me. Then I found this: http://jabide.com/2009/03/parse-blackberry-ipd-files/ He posted a perl script that claims to extract the files. I copied and pasted the code and it did list all the different databases in my .ipd file, I was elated that a cool solution like this was published. I followed the instructions and garbled data with some discernible ascii was sent to standard output unlike a .csv file like he said it would. This is enough to make a grown man cry. Does anyone out there have a solution to extract my address book contacts from an .ipd file?

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  • SQL Server 2008 alternative for SQL-DMO

    - by alexdelpiero
    Hi! I previously was using SQL-DMO to automatically generate scripts from the database. Now I upgraded to SQL Server 2008 and I don’t want to use this feature anymore since Microsoft will be dropping this feature off. Is there any other alternative I can use to connect to a server and generate scripts automatically from a database? Any answer is welcome. Thanks in advance. This is the procedure i was previously using: CREATE PROC GenerateSP ( @server varchar(30) = null, @uname varchar(30) = null, @pwd varchar(30) = null, @dbname varchar(30) = null, @filename varchar(200) = 'c:\script.sql' ) AS DECLARE @object int DECLARE @hr int DECLARE @return varchar(200) DECLARE @exec_str varchar(2000) DECLARE @spname sysname SET NOCOUNT ON -- Sets the server to the local server IF @server is NULL SELECT @server = @@servername -- Sets the database to the current database IF @dbname is NULL SELECT @dbname = db_name() -- Sets the username to the current user name IF @uname is NULL SELECT @uname = SYSTEM_USER -- Create an object that points to the SQL Server EXEC @hr = sp_OACreate 'SQLDMO.SQLServer', @object OUT IF @hr <> 0 BEGIN PRINT 'error create SQLOLE.SQLServer' RETURN END -- Connect to the SQL Server IF @pwd is NULL BEGIN EXEC @hr = sp_OAMethod @object, 'Connect', NULL, @server, @uname IF @hr <> 0 BEGIN PRINT 'error Connect' RETURN END END ELSE BEGIN EXEC @hr = sp_OAMethod @object, 'Connect', NULL, @server, @uname, @pwd IF @hr <> 0 BEGIN PRINT 'error Connect' RETURN END END --Verify the connection EXEC @hr = sp_OAMethod @object, 'VerifyConnection', @return OUT IF @hr <> 0 BEGIN PRINT 'error VerifyConnection' RETURN END SET @exec_str = 'DECLARE script_cursor CURSOR FOR SELECT name FROM ' + @dbname + '..sysobjects WHERE type = ''P'' ORDER BY Name' EXEC (@exec_str) OPEN script_cursor FETCH NEXT FROM script_cursor INTO @spname WHILE (@@fetch_status <> -1) BEGIN SET @exec_str = 'Databases("'+ @dbname +'").StoredProcedures("'+RTRIM(UPPER(@spname))+'").Script(74077,"'+ @filename +'")' EXEC @hr = sp_OAMethod @object, @exec_str, @return OUT IF @hr <> 0 BEGIN PRINT 'error Script' RETURN END FETCH NEXT FROM script_cursor INTO @spname END CLOSE script_cursor DEALLOCATE script_cursor -- Destroy the object EXEC @hr = sp_OADestroy @object IF @hr <> 0 BEGIN PRINT 'error destroy object' RETURN END GO

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  • Handling dependencies with IoC that change within a single function call

    - by Jess
    We are trying to figure out how to setup Dependency Injection for situations where service classes can have different dependencies based on how they are used. In our specific case, we have a web app where 95% of the time the connection string is the same for the entire Request (this is a web application), but sometimes it can change. For example, we might have 2 classes with the following dependencies (simplified version - service actually has 4 dependencies): public LoginService (IUserRepository userRep) { } public UserRepository (IContext dbContext) { } In our IoC container, most of our dependencies are auto-wired except the Context for which I have something like this (not actual code, it's from memory ... this is StructureMap): x.ForRequestedType().Use() .WithCtorArg("connectionString").EqualTo(Session["ConnString"]); For 95% of our web application, this works perfectly. However, we have some admin-type functions that must operate across thousands of databases (one per client). Basically, we'd want to do this: public CreateUserList(IList<string> connStrings) { foreach (connString in connStrings) { //first create dependency graph using new connection string ???? //then call service method on new database _loginService.GetReportDataForAllUsers(); } } My question is: How do we create that new dependency graph for each time through the loop, while maintaining something that can easily be tested?

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  • Setting up a multi-site CMS, collecting thoughts about the DB schema

    - by Ben Fransen
    Hello all, I'm collecting some thoughts about creating a multisite CMS. In my opinion there are two major approaches. All data is stored into 1 database, giving me the advantage of single point of updates; Seperated databases, so each client has its own database. Giving me the advantage to measure bandwith. Option 1 gives me the disadvantage of measuring bandwith while option is giving me the disadvantage of a single point of update structure. Are there any generic approaches for creating a sort of update system? So my clients can download a small package (maybe a zip with a conf file to tell the updatescript where to put all the files and how to extend the database??) Do you guys have some thougths about the best solution for a situation like this? I have my own webserver, full access to all resources and I'm developing in PHP with MySQL as DBMS. I hope to hear from you and I surely appreciate any effort you make to help me further! Greets from Holland, Ben Fransen

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  • Beginner SQL question: querying gold and silver tag badges in Stack Exchange Data Explorer

    - by polygenelubricants
    I'm using the Stack Exchange Data Explorer to learn SQL, but I think the fundamentals of the question is applicable to other databases. I'm trying to query the Badges table, which according to Stexdex (that's what I'm going to call it from now on) has the following schema: Badges Id UserId Name Date This works well for badges like [Epic] and [Legendary] which have unique names, but the silver and gold tag-specific badges seems to be mixed in together by having the same exact name. Here's an example query I wrote for [mysql] tag: SELECT UserId as [User Link], Date FROM Badges Where Name = 'mysql' Order By Date ASC The (slightly annotated) output is: as seen on stexdex: User Link Date --------------- ------------------- // all for silver except where noted Bill Karwin 2009-02-20 11:00:25 Quassnoi 2009-06-01 10:00:16 Greg 2009-10-22 10:00:25 Quassnoi 2009-10-31 10:00:24 // for gold Bill Karwin 2009-11-23 11:00:30 // for gold cletus 2010-01-01 11:00:23 OMG Ponies 2010-01-03 11:00:48 Pascal MARTIN 2010-02-17 11:00:29 Mark Byers 2010-04-07 10:00:35 Daniel Vassallo 2010-05-14 10:00:38 This is consistent with the current list of silver and gold earners at the moment of this writing, but to speak in more timeless terms, as of the end of May 2010 only 2 users have earned the gold [mysql] tag: Quassnoi and Bill Karwin, as evidenced in the above result by their names being the only ones that appear twice. So this is the way I understand it: The first time an Id appears (in chronological order) is for the silver badge The second time is for the gold Now, the above result mixes the silver and gold entries together. My questions are: Is this a typical design, or are there much friendlier schema/normalization/whatever you call it? In the current design, how would you query the silver and gold badges separately? GROUP BY Id and picking the min/max or first/second by the Date somehow? How can you write a query that lists all the silver badges first then all the gold badges next? Imagine also that the "real" query may be more complicated, i.e. not just listing by date. How would you write it so that it doesn't have too many repetition between the silver and gold subqueries? Is it perhaps more typical to do two totally separate queries instead? What is this idiom called? A row "partitioning" query to put them into "buckets" or something?

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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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  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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