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• Get a DB result with a value between two columns values

  - by vitto

  Hi, I have a database situation where I'd like to get a user profile row by a user age range. this is my db: table_users username age email url pippo 15 [email protected] http://example.com pluto 33 [email protected] http://example.com mikey 78 [email protected] http://example.com table_profiles p_name start_age_range stop_age_range young 10 29 adult 30 69 old 70 inf I use MySQL and PHP but I don't know if there is some specific tacnique to do this and of course if it's possible. # so something like: SELECT * FROM table_profiles AS profiles INNER JOIN table_users AS users # can I do something like this? ON users.age IS BETWEEN profiles.start_age_range AND profiles.stop_age_range

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• Eager loading in EF1.0

  - by Dave Swersky

  I have a many-to-many relationship: Application - Applications_Servers - Server This is set up in my Entity Data Model and all is well. My problem is that I'd like to eager-load the whole graph of Applications so that I have an IEnumerable<Applications>, each Application member populated with the Servers collection associated by the many-to-many relationship. Normally this wouldn't be a problem, but according to my research there must be a navigation property between Application and Server. This is not the case for me because my Applications_Servers join table has more in it than just the two keys. Therefore, there is no navigation property directly between Application and Server, and this doesn't work: var apps = (from a in context.Application.Include("Server") select a).ToList(); I get an error saying there is no navigation property on Application called "Server", and that's correct, there is none. How do I write the query to eager-load my Applications with their Servers in this case?

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• How difficult is it for an old-school programmer to pick up an FPGA kit and make something useful wi

  - by JUST MY correct OPINION

  I'm an old, old, old coder. (How old? I've used paper tape in anger.) I've programmed in a lot of languages and under a lot of paradigms (spaghetti, structured, object-oriented, functional and a smattering of logical). I'm getting bored. FPGAs look interesting to me. I have the crazy notion of resurrecting some of the ancient hardware I worked on in the days using FPGAs. I know this can be done because I've seen PDP-10 and PDP-11 implementations in FPGAs. I'd like to do the same for a few machines that are perhaps not as popular as those two, however. While I am an old, old coder, what I am not is an electronics or computer systems engineer. I'll be learning from scratch if I go down this path. My question, therefore, is two-fold: How difficult will it be for this old dinosaur to pick up and learn FPGAs to the point that interesting (not necessarily practical -- more from a hobbyist perspective) projects can be made? What should I start with learning-wise to go down this path? I know where to get FPGA kits, but I haven't found anything like "FPGAs for Complete Dinosaurs" yet anywhere out there.

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• Do I need to include all fields in my entity framework model

  - by Jim B

  Quick question for everyone: Do I need to include all the database table fields on my EF model? For example; I've created a sub-model that only deals with tblPayment and associated tables. Now, I need to write a LINQ query to get some information about items. I would typically get this by joining tblPayment to tblInvoice to tblInvoiceItem to finally tblOrderItem. I'm wondering if when I add in those other tables, do I need to include all the fields for tblInvoice and tblInvoiceItem? Ideally; I'd just like to keep the fields I'd need to join on, as that would limit the possibility of my sub-model breaking if other fields on those tables are modified/deleted. Can I do this?

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• In a process using lots of memory, how can I spawn a shell without a memory-hungry fork()?

  - by kdt

  On an embedded platform (with no swap partition), I have an application whose main process occupies most of the available physical memory. The problem is that I want to launch an external shell script from my application, but using fork() requires that there be enough memory for 2x my original process before the child process (which will ultimately execl itself to something much smaller) can be created. So is there any way to invoke a shell script from a C program without incurring the memory overhead of a fork()? I've considered workarounds such as having a secondary smaller process which is responsible for creating shells, or having a "watcher" script which I signal by touching a file or somesuch, but I'd much rather have something simpler.

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• build SQL query string using user input

  - by user175084

  i have to make a string by using the values which the user selects on the webpage suppose i need to display files for multiple machines with differnt search criteria.. i currently use this code: DataTable dt = new DataTable(); SqlConnection connection = new SqlConnection(); connection.ConnectionString = ConfigurationManager.ConnectionStrings["DBConnectionString"].ConnectionString; connection.Open(); SqlCommand sqlCmd = new SqlCommand("SELECT FileID FROM Files WHERE MachineID=@machineID and date= @date", connection); SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCmd); sqlCmd.Parameters.AddWithValue("@machineID", machineID); sqlCmd.Parameters.AddWithValue("@date", date); sqlDa.Fill(dt); now this is fixed query where the user just has one machine and just selects one date... i want to make a query in which the user has multiple search options like type or size if he wants depending on what he selects also if he can select multiple machines.. SELECT FileID FROM Files WHERE (MachineID=@machineID1 or MachineID = @machineID2...) and (date= @date and size=@size and type=@type... ) all of this happens in runtime... other wise i have to create a for loop to put multiple machines one by one... and have multiple queries depending on the case the user selected... this is quiet interesting and i could use some help... thanks

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• Howto check if a object is connected to another in hibernate

  - by codevourer

  Imagine two domain object classes, A and B. A has a bidirectional one-to-many relationship to B. A is related to thousands of B. The relations must be unique, it's not possible to have a duplicate. To check if an instance of B is already connected to a given instance of A, we could perform an easy INNER JOIN but this will only ensure the already persisted relations. What about the current transient relations? class A { @OneToMany private List<B> listOfB; } If we access the listOfB and perform a check of contains() this will fetch all the connected instances of B lazy from the datasource. I only want to validate them by their primary-key. Is there an easy solution where I can do things like "Does this instance of A is connected with this instance of B?" Without loading all these data into memory and perform a based on collections?

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• DBCC CHECKDB WITH DATA_PURITY gives out of range error

  - by Mark Allison

  Hi there, I have restore a SQL Server 2000 database onto SQL Server 2005 and then run DBCC CHECKDB WITH DATA_PURITY and I get this error: Msg 2570, Level 16, State 3, Line 2 Page (1:19558), slot 13 in object ID 181575685, index ID 1, partition ID 293374720802816, alloc unit ID 11899744092160 (type "In-row data"). Column "NumberOfShares" value is out of range for data type "numeric". Update column to a legal value. The column NumberOfShares is a numeric (19,6) data type. If I run the following select max (NumberOfShares) from AUDIT_Table select min (NumberOfShares) from AUDIT_Table I get: 22678647.839110 -1845953000.000000 These values are inside the bounds of a numeric (19,6) so I'm not sure why the DBCC check fails. Any ideas to find out why it fails? Do I need to use DBCC PAGE? How would you troubleshoot this? Thanks, Mark.

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• How to handle large table in MySQL ?

  - by Frantz Miccoli

  I've a database used to store items and properties about these items. The number of properties is extensible, thus there is a join table to store each property associated to an item value. CREATE TABLE `item_property` ( `property_id` int(11) NOT NULL, `item_id` int(11) NOT NULL, `value` double NOT NULL, PRIMARY KEY (`property_id`,`item_id`), KEY `item_id` (`item_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; This database has two goals : storing (which has first priority and has to be very quick, I would like to perform many inserts (hundreds) in few seconds), retrieving data (selects using item_id and property_id) (this is a second priority, it can be slower but not too much because this would ruin my usage of the DB). Currently this table hosts 1.6 billions entries and a simple count can take up to 2 minutes... Inserting isn't fast enough to be usable. I'm using Zend_Db to access my data and would really be happy if you don't suggest me to develop any php side part. Thanks for your advices !

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• What are good resources for computer graphics basics?

  - by Hanno Fietz

  During Flex programming, I recently ran into several questions (about box models, ways to join lines and misaligning pixels [on doctype]) regarding computer graphics and layout, where I felt that I lacked some basic background on things like concepts like the box model approaches mapping real numbers to a pixel raster (like font anti-aliasing) conventions found across drawing engines, like do you count y coordinates from top or bottom, and why I feel that reading some basic Wikipedia articles, books or tutorials on these subjects might help in phrasing my questions more specifically and debugging my code more systematically. I have repeatedly found myself writing tiny test apps in Flex, just to find out how the APIs do very basic stuff. My assumption would be that if I knew the right vocabulary and some general concepts, I could solve these questions much faster.

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• How do I do multiple has_and_belongs_to_many associations between the same two classes?

  - by Ermin

  I have the following setup: class Publication < ActiveRecord::Base has_and_belongs_to_many :authors, :class_name=>'Person', :join_table => 'authors_publications' has_and_belongs_to_many :editors, :class_name=>'Person', :join_table => 'editors_publications' end class Person < ActiveRecord::Base has_and_belongs_to_many :publications end With this setup I can do stuff like Publication.first.authors. But if I want to list all publications in which a person is involved Person.first.publications, an error about a missing join table people_publications it thrown. How could I fix that? Should I maybe switch to separate models for authors and editors? It would however introduce some redundancy to the database, since a person can be an author of one publication and an editor of another.

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• concatenate multi values in one record without duplication

  - by mikehjun

  I have a dbf table like below which is the result of one to many join from two tables. I want to have unique zone values from one Taxlot id field. table name: input table tid ----- zone 1 ------ A 1 ------ A 1 ------ B 1 ------ C 2 ------ D 2 ------ E 3 ------ C Desirable output table table name: input table tid ----- zone 1 ------ A, B, C 2 ------ D, E 3 ------ C I got some help but couldn't make it to work. inputTbl = r"C:\temp\input.dbf" taxIdZoningDict = {} searchRows = gp.searchcursor(inputTbl) searchRow = searchRows.next() while searchRow: if searchRow.TID in taxIdZoningDict: taxIdZoningDict[searchRow.TID].add(searchRow.ZONE) else: taxIdZoningDict[searchRow.TID] = set() #a set prevents dulpicates! taxIdZoningDict[searchRow.TID].add(searchRow.ZONE) searchRow = searchRows.next() outputTbl = r"C:\temp\output.dbf" gp.CreateTable_management(r"C:\temp", "output.dbf") gp.AddField_management(outputTbl, "TID", "LONG") gp.AddField_management(outputTbl, "ZONES", "TEXT", "", "", "20") tidList = taxIdZoningDict.keys() tidList.sort() #sorts in ascending order insertRows = gp.insertcursor(outputTbl) for tid in tidList: concatString = "" for zone in taxIdZoningDict[tid] concatString = concatString + zone + "," insertRow = insertRows.newrow() insertRow.TID = tid insertRow.ZONES = concatString[:-1] insertRows.insertrow(insertRow) del insertRow del insertRows

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• Help needed in AdventureWorks in a sql query.

  - by vaibhav

  I was just playing with adventureworks database in sqlserver. I got stuck in a query. I wanted to Select all titles from HumanResources.Employee which are either 'Male' or 'Female' but not both. i.e if title Accountant is Male and Female both I want to leave that title. I need only those titles where Gender is either Male or Female. I have done this till yet. select distinct(title) from humanresources.employee where gender='M' select distinct(title) from humanresources.employee where gender='F' Probably a join between these two queries, would work. But If you have any other solution, please let me know. It is not a homework. :) Thanks in advance.

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• mongoDB many to many with one query?

  - by PowderKeg

  in mysql i use JOIN and one query is no problem. what about mongo? imagine categories and products. products may have more categories. categories may have more product. (many to many structure) and administrator may edit categories in administration (categories must be separated) its possible write product with categories names in one query? i used this structure categories { name:"categoryName", product_id:["4b5783300334000000000aa9","5783300334000000000aa943","6c6793300334001000000006"] } products { name:"productName", category_id:["4b5783300334000000000bb9","5783300334000000000bb943","6c6793300334001000000116"] } now i can simply get all product categories, and product in some category and categories alone for editation. but if i want write product with categories names i need two queries - one to get product categories id and second to get categories names from categories by that ids. is this the right way? or this structure is unsuitable? i would like to have only one query but i dont know if its possible.

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• Call .NET Webservice with Android

  - by Lasse P

  Hi, I know this question has been asked here before, but I don't think those answers were adequate for my needs. We have a SOAP webservice that is used for an iPhone application, but it is possible that we need an Android specific version or a proxy of the service, so we have the option to go with either SOAP or JSON. I have a few concerns about both methods: SOAP solution: Is it possible to generate java source code from a WSDL file, if so, will it include some kind of proxy class to invoke the webservice and will it work in the Android environment at all? Google has not provided any SOAP library in Android, so i need to use 3rd party, any suggestion? What about the performance/overhead with parsing and transmitting SOAP xml over the wire versus the JSON solution? JSON solution: There is a few classes in the Android sdk that will let me parse JSON, but does it support generic parsing, like if I want the result to be parsed as a complex type? Or would I need to implement that myself? I have read about 2 libraries before here on Stackoverflow, GSON an Jackson. What is the difference performance and usability (from a developers perspective) wise? Do you guys have any experince with either of those libraries? So i guess the big question is, what method to go with? I hope you can help me out. Thanks in advance :-)

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• Is my TFS2010 backup/restore hosed?

  - by bwerks

  Hi all, I recently set up a sandbox TFS to test TFS-specific features without interfering with the production TFS. I was happy I did this sooner than I thought--I hadn't been backing up the encryption key from SSRS and upon restoring the reporting databases, they remained inactive, requiring initialization that could only come from applying the encryption key. Said encryption key was lost when I nuked the partition after backing up the TFS databases. The only option I seemed to have is to delete the encrypted data. I'm fine with this, since there wasn't much in there to begin with, however once they're deleted I'm not quite sure how to configure TFS to recognize a new installation of these services while using the restored versions of everything else. Unfortunately, the TFS help file doesn't seem to account for this state though. Is there a way to essentially rebuild the reporting and analysis databases? Or are they gone forever?

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• Partioning the Table into .net - Creating columner database.

  - by Omky

  Hello Geeks, I am developing some tool for BI. There are terms like Fact, Dimensions and Measures. My application will connect to the normal database and read the data from that table. Now, I want to convert all this data into columnar database. That is all the columns from this table will be transfer into 3 tables each. Consider below table:- ID Product 1 XYZ 2 ABC 3 ABC Now, I want to convert the Product column i.e. dimension into 3 tables. dim_product_table:- ID Product 1 XYZ 2 ABC dim_product_fmk(fact map by key):- Where we will store key-value pair of Key Row 1 1 1 2 2 3 dim_product_fmr(fact map by row):- The above table will be reversed. Row Key 1 1 2 1 3 2 The another requirement is all above table should be generated dynamically and I should be able to JOIN all those. Can anybody help me? Thanks in advance.

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• Including associations optimization in Rails

  - by Vitaly

  Hey, I'm looking for help with Ruby optimization regarding loading of associations on demand. This is simplified example. I have 3 models: Post, Comment, User. References are: Post has many comments and Comment has reference to User (:author). Now when I go to the post page, I expect to see post body + all comments (and their respective authors names). This requires following 2 queries: select * from Post -- to get post data (1 row) select * from Comment inner join User -- to get comment + usernames (N rows) In the code I have: Post.find(params[:id], :include => { :comments => [:author] } But it doesn't work as expected: as I see in the back end, there're still N+1 hits (some of them are cached though). How can I optimize that?

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• How to split movie and play parts to look as a whole?

  - by luksow

  I'm writing software which is demonstraiting video on demand service. One of the feature is something similiar to IIS Smooth Streaming - I want to adjust quality to the bandwith of the client. My idea is, to split single movie into many, let's say - 2 seconds parts, in different qualities and then send it to the client and play them. The point is that for example first part can be in very high quality, and second in really poor (if the bandwith seems to be poor). The question is - do you know any software that allows me to cut movies precisly? For example ffmpeg splits movies in a way that join is visible and really annoying (seconds are the measure of precision). I use qt + phonon as a player if it matters. Or maybe you know any better way to provide such feature, without splitting movie into parts?

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• PHP modifying and combining array

  - by Industrial

  Hi everyone, I have a bit of an array headache going on. The function does what I want, but since I am not yet to well acquainted with PHP:s array/looping functions, so thereby my question is if there's any part of this function that could be improved from a performance-wise perspective? I tried to be as complete as possible in my descriptions in each stage of the functions which shortly described prefixes all keys in an array, fill up eventual empty/non-valid keys with '' and removes the prefixes before returning the array: $var = myFunction ( array('key1', 'key2', 'key3', '111') ); function myFunction ($keys) { $prefix = 'prefix_'; $keyCount = count($keys); // Prefix each key and remove old keys for($i=0;$i<$keyCount; $i++){ $keys[] = $prefix.$keys[$i]; unset($keys[$i]); } // output: array('prefix_key1', 'prefix_key2', 'prefix_key3', '111) // Get all keys from memcached. Only returns valid keys $items = $this->memcache->get($keys); // output: array('prefix_key1' => 'value1', 'prefix_key2' => 'value2', 'prefix_key3'=>'value3) // note: key 111 was not found in memcache. // Fill upp eventual keys that are not valid/empty from memcache $return = $items + array_fill_keys($keys, ''); // output: array('prefix_key1' => 'value1', 'prefix_key2' => 'value2', 'prefix_key3'=>'value3, 'prefix_111' => '') // Remove the prefixes for each result before returning array to application foreach ($return as $k => $v) { $expl = explode($prefix, $k); $return[$expl[1]] = $v; unset($return[$k]); } // output: array('key1' => 'value1', 'key2' => 'value2', 'key3'=>'value3, '111' => '') return $return; } Thanks a lot!

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• running Hadoop software on office computers (when they are idle)

  - by Shahbaz

  Is there a project which helps setup a Hadoop cluster on office desktops, when they are idle? I'd like to experiment with Hadoop/MR/hbase but don't have acces to 5-10 computers. The computers at work are idle after hours and are connected to each other through a very high speed connection. What's more, data on these computers stays within our network so there is no privacy issue. In order for this to work I need a fairly light weight monitor running on each machine. When the computer has been idle for X hours, it will join the cluster. If the user logs on, it has to drop out of the cluster and return all CPU/memory back. Does something like this exist?

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• Problem with SQLite executemany

  - by Strider1066

  I can't find my error in the following code. When it is run a type error is given for line: cur.executemany(sql % itr.next()) = 'function takes exactly 2 arguments (1 given), import sqlite3 con = sqlite3.connect('test.sqlite') cur = con.cursor() cur.execute("create table IF NOT EXISTS fred (dat)") def newSave(className, fields, objData): sets = [] itr = iter(objData) if len(fields) == 1: sets.append( ':' + fields[0]) else: for name in fields: sets.append( ':' + name) if len(sets)== 1: colNames = sets[0] else: colNames = ', '.join(sets) sql = " '''insert into %s (%s) values(%%s)'''," % (className, colNames) print itr.next() cur.executemany(sql % itr.next()) con.commit() if __name__=='__main__': newSave('fred', ['dat'], [{'dat':1}, {'dat':2}, { 'dat':3}, {'dat':4}]) I would appreciate your thoughts.

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• How refresh a DrawingArea in PyGTK ?

  - by Lialon

  I have an interface created with Glade. It contains a DrawingArea and buttons. I tried to create a Thread to refresh every X time my Canva. After a few seconds, I get error messages like: "X Window Server 0.0", "Fatal Error IO 11" Here is my code : import pygtk pygtk.require("2.0") import gtk import Canvas import threading as T import time import Map gtk.gdk.threads_init() class Interface(object): class ThreadCanvas(T.Thread): """Thread to display the map""" def __init__(self, interface): T.Thread.__init__(self) self.interface = interface self.started = True self.start() def run(self): while self.started: time.sleep(2) self.interface.on_canvas_expose_event() def stop(self): self.started = False def __init__(self): self.interface = gtk.Builder() self.interface.add_from_file("interface.glade") #Map self.map = Map.Map(2,2) #Canva self.canvas = Canvas.MyCanvas(self.interface.get_object("canvas"),self.game) self.interface.connect_signals(self) #Thread Canvas self.render = self.ThreadCanvas(self) def on_btnChange_clicked(self, widget): #Change map self.map.change() def on_interface_destroy(self, widget): self.render.stop() self.render.join() self.render._Thread__stop() gtk.main_quit() def on_canvas_expose_event(self): st = time.time() self.canvas.update(self.map) et = time.time() print "Canvas refresh in : %f times" %(et-st) def main(self): gtk.main() How can i fix these errors ?

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• How to save the world from your computer?

  - by Francisco Garcia

  Sometimes I miss the "help other people" factor within computer related careers. Sure that out there I could find many great projects improving society, but that is not common. However there are little things that we all can do to make this a better place beyond trying to erradicate annoynig stuff such as Visual Basic. You could join a cloud computing network such as World Community Grid to fight cancer. Write a charityware application such as Vim, improve an office IT infrastructure to support telecommuting and reduce CO2 emissions, use an ebook reader for saving paper... what else would you? which projects do you think can have an impact?

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• MySQL : delete from table that is used in the where clause

  - by Eric

  I am writing a small script to synchronize 2 MySQL tables ( t1 to be 'mirrored' to t2 ) In a step I would like to delete rows inside t2 that has been delete in t1 with the same id. I tried this query : delete from t2 where t2.id in ( select t2.id left join t1 on (t1.id=t2.id) where t1.id is null ) But Mysql forbid me to use t2 in the same time in the delete and in the select (sound logical by the way) Of course, I can split the query into 2 queries : first select IDs, then delete rows with these IDs. My question : do you have a cleaner way to delete row from t2 that does not exist anymore in t1 ? with one query only ?

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