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  • How to insert records in master/detail relationship

    - by croceldon
    I have two tables: OutputPackages (master) |PackageID| OutputItems (detail) |ItemID|PackageID| OutputItems has an index called 'idxPackage' set on the PackageID column. ItemID is set to auto increment. Here's the code I'm using to insert masters/details into these tables: //fill packages table for i := 1 to 10 do begin Package := TfPackage(dlgSummary.fcPackageForms.Forms[i]); if Package.PackageLoaded then begin with tblOutputPackages do begin Insert; FieldByName('PackageID').AsInteger := Package.ourNum; FieldByName('Description').AsString := Package.Title; FieldByName('Total').AsCurrency := Package.Total; Post; end; //fill items table for ii := 1 to 10 do begin Item := TfPackagedItemEdit(Package.fc.Forms[ii]); if Item.Activated then begin with tblOutputItems do begin Append; FieldByName('PackageID').AsInteger := Package.ourNum; FieldByName('Description').AsString := Item.Description; FieldByName('Comment').AsString := Item.Comment; FieldByName('Price').AsCurrency := Item.Price; Post; //this causes the primary key exception end; end; end; end; This works fine as long as I don't mess with the MasterSource/MasterFields properties in the IDE. But once I set it, and run this code I get an error that says I've got a duplicate primary key 'ItemID'. I'm not sure what's going on - this is my first foray into master/detail, so something may be setup wrong. I'm using ComponentAce's Absolute Database for this project. How can I get this to insert properly? Update Ok, I removed the primary key restraint in my db, and I see that for some reason, the autoincrement feature of the OutputItems table isn't working like I expected. Here's how the OutputItems table looks after running the above code: ItemID|PackageID| 1 |1 | 1 |1 | 2 |2 | 2 |2 | I still don't see why all the ItemID values aren't unique.... Any ideas?

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  • Simple Prototype.js code to select multiple elements with the same classname

    - by stephemurdoch
    I have one link with an id of "link", and I use the javascript below to open that link up in a modalbox: #In my template I have: <a href="some/path" id="link">link</a> #Then in my application.js file I have: document.observe('dom:loaded', function() { $('login-link').observe('click', function(event) { event.stop(); Modalbox.show(this.href,{title: 'some title', width: 500}); }); }) Since id's must be unique, this javascript only works for one element per page so I use it to observe my login-link and it has served me well. Until now. I want to use the same javascript to observe multiple links which have classnames instead of id's as below: <a href="link/to/some/stuff" class="link">link 1</a> <a href="link/to/some/other/stuff" class="link">link 2</a> When I do this, I can't get any of the links to open in a modalbox. If I change the class to an id for each link, then I can get the first link in the list to open in a modalbox. I've tried to use the '$$' notation to build an array of links in my javascript (shown below) but if I do that, then none of the links open correctly #document.observe method removed for display purposes $$('link').observe('click', function(event) { event.stop(); Modalbox.show(this.href,{title: 'some title', width: 500} ); }); My javascript skills obviously suck. Does anyone know how to fix the problem?

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  • Java: easiest way to package both Java 1.5 and 1.6 code

    - by WizardOfOdds
    I want to package a piece of code that absolutely must run on Java 1.5. There's one part of the code where the program can be "enhanced" if the VM is an 1.6 VM. Basically it's this method: private long[] findDeadlockedThreads() { // JDK 1.5 only supports the findMonitorDeadlockedThreads() // method, so you need to comment out the following three lines if (mbean.isSynchronizerUsageSupported()) return mbean.findDeadlockedThreads(); else return mbean.findMonitorDeadlockedThreads(); } What would be easiest way to have this compile on 1.5 and yet do the 1.6 method calls when on 1.6 ? In the past I've done something similar by compiling a unique 1.6 class that I would package with my app and instantiate using a ClassLoader when on 1.6 (because an 1.6 JVM is perfectly fine mixing 0x32 and 0x31 classes), but I think it's a bit overkill (and a bit painful because during the build process you have to build both 0x31 and 0x32 .class files). How should I go if I wanted to compile the above method on 1.5? Maybe using reflection but then how (I'm not familiar at all with reflection) Note: if you're curious, the above method comes from this article: http://www.javaspecialists.eu/archive/Issue130.html (but I don't want to "comment the three lines" like in the article, I want this to compile and run on both 1.5 and 1.6)

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  • AVAudioPlayer not unloading cached memory after each new allocation

    - by Rob
    I am seeing in Instruments that when I play a sound via the standard "AddMusic" example method that Apple provides, it allocates 32kb of memory via the prepareToPlay call (which references the AudioToolBox framework's Cache_DataSource::ReadBytes function) each time a new player is allocated (i.e. each time a different sound is played). However, that cached data never gets released. This obviously poses a huge problem if it doesn't get released and you have a lot of sound files to play, since it tends to keep allocating memory and eventually crashes if you have enough unique sound files (which I unfortunately do). Have any of you run across this or what am I doing wrong in my code? I've had this issue for a while now and it's really bugging me since my code is verbatim of what Apple's is (I think). How I call the function: - (void)playOnce:(NSString *)aSound { // Gets the file system path to the sound to play. NSString *soundFilePath = [[NSBundle mainBundle] pathForResource:aSound ofType:@"caf"]; // Converts the sound's file path to an NSURL object NSURL *soundURL = [[NSURL alloc] initFileURLWithPath: soundFilePath]; self.soundFileURL = soundURL; [soundURL release]; AVAudioPlayer * newAudio=[[AVAudioPlayer alloc] initWithContentsOfURL: soundFileURL error:nil]; self.theAudio = newAudio; // automatically retain audio and dealloc old file if new m4a file is loaded [newAudio release]; // release the audio safely // this is where the prior cached data never gets released [theAudio prepareToPlay]; // set it up and play [theAudio setNumberOfLoops:0]; [theAudio setVolume: volumeLevel]; [theAudio setDelegate: self]; [theAudio play]; } and then theAudio gets released in the dealloc method of course.

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  • Django db encoding

    - by realshadow
    Hey, I have a little problem with encoding. The data in db is ok, when I select the data in php its ok. Problem comes when I get the data and try to print it in the template, I get - Å port instead of Šport, etc. Everything is set to utf-8 - in settings.py, meta tags in template, db table and I even have unicode method specified for the model, but nothing seems to work. I am getting pretty hopeless here... Here is some code: class Category_info(models.Model): objtree_label_id = models.AutoField(primary_key = True) node_id = models.IntegerField(unique = True) language_id = models.IntegerField() label = models.CharField(max_length = 255) type_id = models.IntegerField() class Meta: db_table = 'objtree_labels' def __unicode__(self): return self.label I have even tried with return u"%s" % self.label. Here is the view: def categories_list(request): categories_list = Category.objects.filter(parent_id = 1, status = 1) paginator = Paginator(categories_list, 10) try: page = int(request.GET.get('page', 1)) except ValueError: page = 1 try: categories = paginator.page(page) except (EmptyPage, InvalidPage): categories = paginator.page(paginator.num_pages) return render_to_response('categories_list.html', {'categories': categories}) Maybe I am just blind and/or stupid, but it just doesnt work. So any help is appreciated, thanks in advance. Regards

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  • How can I improve this search usability?

    - by Craig Whitley
    This is the first real programming attempt of mine, and theres some major flaws. It's a learning project, and I'm currently re-writing the entire thing as my php is is really messy. I really want to get an idea on how I can improve the actual usability and accesibility of the site at the same time though - so I know how to implement it correctly. The website is basically a comparison website for gameserver hosting. As I mentioned, its a learning project and I don't actually expect any revenue from it. At the moment theres only test data in it, so in the game input box select either 'Battlefied Bad Company 2' or 'Call of Duty 4: Modern Warfare' and ignore the actual search results. http://www.laglessfrag.com I wasn't really sure how to work the search functionality. Basically when you click a game in the drop down box, it sends an ajax request and finds all the locations available to that specific game in the database. After selecting the country theres another ajax to find all the citys available to the game in that country - which gives me the two unique identifiers I need to create the search results. One major and fundamental flaw is that without javascript enabled, the site ceases to function. I'll overcome that in the next re-write, but without the ajax functionality stopping the user 'going wrong' - how can I implement a search that requires two fields without creating extra steps in new pages after form submissions? I'm also no designer so my whole layout and css is a bit rubbish, but this was mainly a learning project as I'm interested in applications / programming rather than design. It's also slow as its on shared hosting, but if I can get it to work correctly then I'm not impartial to chucking a bit of money at it for faster hosting and maybe a bit of advertising and seeing where it goes (if anywhere!). Any info appreciated.

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  • MySQL - optimising selection across two linked tables

    - by user293594
    I have two MySQL tables, states and trans: states (200,000 entries) looks like: id (INT) - also the primary key energy (DOUBLE) [other stuff] trans (14,000,000 entries) looks like: i (INT) - a foreign key referencing states.id j (INT) - a foreign key referencing states.id A (DOUBLE) I'd like to search for all entries in trans with trans.A 30. (say), and then return the energy entries from the (unique) states referenced by each matching entry. So I do it with two intermediate tables: CREATE TABLE ij SELECT i,j FROM trans WHERE A30.; CREATE TABLE temp SELECT DISTINCT i FROM ij UNION SELECT DISTINCT j FROM ij; SELECT energy from states,temp WHERE id=temp.i; This seems to work, but is there any way to do it without the intermediate tables? When I tried to create the temp table with a single command straight from trans: CREATE TABLE temp SELECT DISTINCT i FROM trans WHERE A30. UNION SELECT DISTINCT j FROM trans WHERE A30.; it took a longer (presumably because it had to search the large trans table twice. I'm new to MySQL and I can't seem to find an equivalent problem and answer out there on the interwebs. Many thanks, Christian

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  • ASP.NET DropDownList posting ""

    - by Daniel
    I am using ASP.NET forms version 3.5 in VB I have a dropdownlist that is filled with data from a DB with a list of countries The code for the dropdown list is <label class="ob_label"> <asp:DropDownList ID="lstCountry" runat="server" CssClass="ob_forminput"> </asp:DropDownList> Country*</label> And the code that the list is Dim selectSQL As String = "exec dbo.*******************" ' Define the ADO.NET objects. Dim con As New SqlConnection(connectionString) Dim cmd As New SqlCommand(selectSQL, con) Dim reader As SqlDataReader ' Try to open database and read information. Try con.Open() reader = cmd.ExecuteReader() ' For each item, add the author name to the displayed ' list box text, and store the unique ID in the Value property. Do While reader.Read() Dim newItem As New ListItem() newItem.Text = reader("AllSites_Countries_Name") newItem.Value = reader("AllSites_Countries_Id") CType(LoginViewCart.FindControl("lstCountry"), DropDownList).Items.Add(newItem) Loop reader.Close() CType(LoginViewCart.FindControl("lstCountry"), DropDownList).SelectedValue = 182 Catch Err As Exception Response.Redirect("~/error-on-page/") MailSender.SendMailMessage("*********************", "", "", OrangeBoxSiteId.SiteName & " Error Catcher", "<p>Error in sub FillCountry</p><p>Error on page:" & HttpContext.Current.Request.Url.AbsoluteUri & "</p><p>Error details: " & Err.Message & "</p>") Response.Redirect("~/error-on-page/") Finally con.Close() End Try When the form is submitted an error occurs which says that the string "" cannot be converted to the datatype integer. For some reason the dropdownlist is posting "" rather than the value for the selected country.

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  • How to name multiple versioned ServiceContracts in the same WCF service?

    - by Tor Hovland
    When you have to introduce a breaking change in a ServiceContract, a best practice is to keep the old one and create a new one, and use some version identifier in the namespace. If I understand this correctly, I should be able to do the following: [ServiceContract(Namespace = "http://foo.com/2010/01/14")] public interface IVersionedService { [OperationContract] string WriteGreeting(Person person); } [ServiceContract(Name = "IVersionedService", Namespace = "http://foo.com/2010/02/21")] public interface IVersionedService2 { [OperationContract(Name = "WriteGreeting")] Greeting WriteGreeting2(Person2 person); } With this I can create a service that supports both versions. This actually works, and it looks fine when testing from soapUI. However, when I create a client in Visual Studio using "Add Service Reference", VS disregards the namespaces and simply sees two interfaces with the same name. In order to differentiate them, VS adds "1" to the name of one of them. I end up with proxies called ServiceReference.VersionedServiceClient and ServiceReference.VersionedService1Client Now it's not easy for anybody to see which is the newer version. Should I give the interfaces different names? E.g IVersionedService1 IVersionedService2 or IVersionedService/2010/01/14 IVersionedService/2010/02/21 Doesn't this defeat the purpose of the namespace? Should I put them in different service classes and get a unique URL for each version?

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  • Addresses stored in SQL server have many small variations(errors)

    - by MAW74656
    I have a table in my database which stores packing slips and their information. I'm trying to query that table and get each unique address. I've come close, but I still have many near misses and I'm looking for a way to exclude these near duplicates from my select. Sample Data CompanyCode CompanyName Addr1 City State Zip 10033 UNITED DIE CUTTING & FINISHIN 3610 HAMILTON AVE CLEVELAND Ohio 44114 10033 UNITED DIE CUTTING & FINISHING 3610 HAMILTON AVE CLEVELAND Ohio 44114 10033 UNITED DIE CUTTING & FINISHING 3610 HAMILTON AVE. CLEVELAND Ohio 44114 10033 UNITED DIE CUTTING & FINISHING 3610 HAMILTON AVENUE CLEVELAND Ohio 44114 10033 UNITED DIECUTTING & FINISHING 3610 HAMILTON AVE CLEVELAND Ohio 44144 10033 UNITED FINISHING 3610 HAMILTON AVE CLEVLAND Ohio 44114 10033 UNITED FINISHING & DIE CUTTING 3610 HAMILTON AVE CLEVELAND Ohio 44114 And all I want is 1 record. Is there some way I can get the "Average" record? Meaning, if most of the records say CLEVELAND instead of CLEVLAND, I want my 1 record to say CLEVELAND. Is there any way to par this data down to what I'm looking for? Desired Output CompanyCode CompanyName Addr1 City State Zip 10033 UNITED DIE CUTTING & FINISHING 3610 HAMILTON AVE CLEVELAND Ohio 44114

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  • How do I make the following interaction with mySQL more efficient?

    - by Travis
    I've got an array that contains combinations of unique MySql IDs: For example: [ [1,10,11], [2,10], [3,10,12], [3,12,13,20], [4,12] ] In total there are a couple hundred different combinations of IDs. Some of these combinations are "valid" and some are not. For example, [1,10,11] may be a valid combination, whereas [3,10,12] may be invalid. Combinations are valid or invalid depending on how the data is arranged in the database. Currently I am using a SELECT statement to determine whether or not a specific combination of IDs is valid. It looks something like this: SELECT id1 FROM table WHERE id2 IN ($combination) GROUP BY id1 HAVING COUNT(distinct id2) = $number ...where $combination is one possible combination of IDs (eg 1,10,11) and $number is the number of IDs in that combination (in this case, 3). An invalid combination will return 0 rows. A valid combination will return 1 or more rows. However, to solve the entire set of possible combinations means looping a couple hundred SELECT statements, which I would rather not be doing. I am wondering: Are there any tricks for making this more efficient? Is it possible to submit the entire dataset to mySQL in one go, and have mySQL iterate through it? Any suggestions would be much appreciated. Thanks in advance!

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  • SQLAlchemy: select over multiple tables

    - by ahojnnes
    Hi, I wanted to optimize my database query: link_list = select( columns=[link_table.c.rating, link_table.c.url, link_table.c.donations_in], whereclause=and_( not_(link_table.c.id.in_( select( columns=[request_table.c.recipient], whereclause=request_table.c.donator==donator.id ).as_scalar() )), link_table.c.id!=donator.id, ), limit=20, ).execute().fetchall() and tried to merge those two selects in one query: link_list = select( columns=[link_table.c.rating, link_table.c.url, link_table.c.donations_in], whereclause=and_( link_table.c.active==True, link_table.c.id!=donator.id, request_table.c.donator==donator.id, link_table.c.id!=request_table.c.recipient, ), limit=20, order_by=[link_table.c.rating.desc()] ).execute().fetchall() the database-schema looks like: link_table = Table('links', metadata, Column('id', Integer, primary_key=True, autoincrement=True), Column('url', Unicode(250), index=True, unique=True), Column('registration_date', DateTime), Column('donations_in', Integer), Column('active', Boolean), ) request_table = Table('requests', metadata, Column('id', Integer, primary_key=True, autoincrement=True), Column('recipient', Integer, ForeignKey('links.id')), Column('donator', Integer, ForeignKey('links.id')), Column('date', DateTime), ) There are several links (donator) in request_table pointing to one link in the link_table. I want to have links from link_table, which are not yet "requested". But this does not work. Is it actually possible, what I'm trying to do? If so, how would you do that? Thank you very much in advance!

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  • Toggling between instances of NiftyPlayer on a page - won't stop playing when hidden on IE

    - by Ashley
    Hi, i've got a page with links to MP3s, when the link is clicked I use javascript to show a small Flash player (NiftyPlayer) under the link. When a different link is clicked, the old player is hidden and the new player is revealed. The player auto-starts when the element is shown, and auto-stops when hidden - in Firefox. In IE it will only auto-start and NOT auto-stop. This is what I would like to solve. This is an example HTML with link and player <a href="Beat The Radar - Misunderstood What You Said.mp3" onclick="toggle_visibility('player662431');return false;" class="mp3caption">Misunderstood What You Said</a> <div id="player662431" class="playerhide"><embed src="http://www.xxx.com/shop/flash/player.swf?file=/mp3/Beat The Radar - Misunderstood What You Said.mp3&as=1" quality="high" bgcolor="#000000" width="161" height="13" name="niftyPlayer662431" align="" type="application/x-shockwave-flash" swLiveConnect="true" pluginspage="http://www.macromedia.com/go/getflashplayer"></embed> Here is the javascript (i've got jquery installed to let me hide all the open players on this page apart from the new one) function toggle_visibility(id) { $('.playerhide').hide(); var e = document.getElementById(id); e.style.display = 'block'; } I think what I need to do is start the player manually with javascript (rather than using the autostart as=1 function in the URL string) There is some javascript that comes with NiftyPlayer to allow this EG niftyplayer('niftyPlayer1').play() there is also a stop method. I need some help with javascript - how do I add this call to play into my toggle_visibility function (it has the same unique ID number added to the name of the player as the ID of the div that's being shown, but I don't know how to pull this ID number out of one thing and put it in another) I also would like to be able to do niftyplayer('niftyPlayer1').stop() to stop the audio of the previously running player. Is it possible to store the current ID number somewhere and call it back when needed? Thanks for the help, i'm a PHP programmer who needs some support with Javascript - I know what I want to achieve, just don't know the commands to do it! Thanks

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  • Please help optimizing a long running query (left outer join, with 2 subqueries)

    - by 46and2
    Hi all. The query I need help with is: SELECT d.bn, d.4700, d.4500, ... , p.`Activity Description` FROM ( SELECT temp.bn, temp.4700, temp.4500, .... FROM `tdata` temp GROUP BY temp.bn HAVING (COUNT(temp.bn) = 1) ) d LEFT OUTER JOIN ( SELECT temp2.bn, max(temp2.FPE) AS max_fpe, temp2.`Activity Description` FROM `pdata` temp2 GROUP BY temp2.bn ) p ON p.bn = d.bn; The ... represents other fields that aren't really important to solving this problem. The issue is on the the second subquery - it is not using the index I have created and I am not sure why, it seems to be because of the way TEXT fields are handled. The first subquery uses the index I have created and runs quite snappy, however an explain on the second shows a 'Using temporary; Using filesort'. Please see the indexes I have created in the below table create statements. Can anyone help me optimize this? By way of quick explanation the first subquery is meant to only select records that have unique bn's, the second, while it looks a bit wacky (with the max function there which is not being used in the result set) is making sure that only one record from the right part of the join is included in the result set. My table create statements are CREATE TABLE `tdata` ( `BN` varchar(15) DEFAULT NULL, `4000` varchar(3) DEFAULT NULL, `5800` varchar(3) DEFAULT NULL, .... KEY `BN` (`BN`), KEY `idx_t3010`(`BN`,`4700`,`4500`,`4510`,`4520`,`4530`,`4570`,`4950`,`5000`,`5010`,`5020`,`5050`,`5060`,`5070`,`5100`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 CREATE TABLE `pdata` ( `BN` varchar(15) DEFAULT NULL, `FPE` datetime DEFAULT NULL, `Activity Description` text, .... KEY `BN` (`BN`), KEY `idx_programs_2009` (`BN`,`FPE`,`Activity Description`(100)) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 Thanks!

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  • Best way to get a single value from a DataTable?

    - by PiersMyers
    I have a number of static classes that contain tables like this: using System; using System.Data; using System.Globalization; public static class TableFoo { private static readonly DataTable ItemTable; static TableFoo() { ItemTable = new DataTable("TableFoo") { Locale = CultureInfo.InvariantCulture }; ItemTable.Columns.Add("Id", typeof(int)); ItemTable.Columns["Id"].Unique = true; ItemTable.Columns.Add("Description", typeof(string)); ItemTable.Columns.Add("Data1", typeof(int)); ItemTable.Columns.Add("Data2", typeof(double)); ItemTable.Rows.Add(0, "Item 1", 1, 1.0); ItemTable.Rows.Add(1, "Item 2", 1, 1.0); ItemTable.Rows.Add(2, "Item 3", 2, 0.75); ItemTable.Rows.Add(3, "Item 4", 4, 0.25); ItemTable.Rows.Add(4, "Item 5", 1, 1.0); } public static DataTable GetItemTable() { return ItemTable; } public static int Data1(int id) { DataRow[] dr = ItemTable.Select("Id = " + id); if (dr.Length == 0) { throw new ArgumentOutOfRangeException("id", "Out of range."); } return (int)dr[0]["Data1"]; } public static double Data2(int id) { DataRow[] dr = ItemTable.Select("Id = " + id); if (dr.Length == 0) { throw new ArgumentOutOfRangeException("id", "Out of range."); } return (double)dr[0]["Data2"]; } } Is there a better way of writing the Data1 or Data2 methods that return a single value from a single row that matches the given id?

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  • JavaScript snippet to read and output XML file on page load?

    - by Banderdash
    Hey guys, hoping I might get some help. Have XML file here of a list of books each with unique id and numeral value for whether they are checked out or not. I need a JavaScript snippet that requests the XML file after the page loads and displays the content of the XML file. XML file looks like this: <?xml version="1.0" encoding="UTF-8" ?> <response> <library name="My Library"> <book id="1" checked-out="1"> <authors> <author>John Resig</author> </authors> <title>Pro JavaScript Techniques (Pro)</title> <isbn-10>1590597273</isbn-10> </book> <book id="2" checked-out="0"> <authors> <author>Erich Gamma</author> <author>Richard Helm</author> <author>Ralph Johnson</author> <author>John M. Vlissides</author> </authors> <title>Design Patterns: Elements of Reusable Object-Oriented Software</title> <isbn-10>0201633612</isbn-10> </book> ... </library> </response> Would LOVE any and all help!

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  • What is the best database structure for this scenario?

    - by Ricketts
    I have a database that is holding real estate MLS (Multiple Listing Service) data. Currently, I have a single table that holds all the listing attributes (price, address, sqft, etc.). There are several different property types (residential, commercial, rental, income, land, etc.) and each property type share a majority of the attributes, but there are a few that are unique to that property type. My question is the shared attributes are in excess of 250 fields and this seems like too many fields to have in a single table. My thought is I could break them out into an EAV (Entity-Attribute-Value) format, but I've read many bad things about that and it would make running queries a real pain as any of the 250 fields could be searched on. If I were to go that route, I'd literally have to pull all the data out of the EAV table, grouped by listing id, merge it on the application side, then run my query against the in memory object collection. This also does not seem very efficient. I am looking for some ideas or recommendations on which way to proceed. Perhaps the 250+ field table is the only way to proceed. Just as a note, I'm using SQL Server 2012, .NET 4.5 w/ Entity Framework 5, C# and data is passed to asp.net web application via WCF service. Thanks in advance.

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  • Architecture for data layer that uses both localStorage and a REST remote server

    - by Zack
    Anybody has any ideas or references on how to implement a data persistence layer that uses both a localStorage and a REST remote storage: The data of a certain client is stored with localStorage (using an ember-data indexedDB adapter). The locally stored data is synced with the remote server (using ember-data RESTadapter). The server gathers all data from clients. Using mathematical sets notation: Server = Client1 ? Client2 ? ... ? ClientN where, in general, a record may not be unique to a certain client. Here are some scenarios: A client creates a record. The id of the record can not set on the client, since it may conflict with a record stored on the server. Therefore a newly created record needs to be committed to the server - receive the id - create the record in localStorage. A record is updated on the server, and as a consequence the data in localStorage and in the server go out of sync. Only the server knows that, so the architecture needs to implement a push architecture (?) Would you use 2 stores (one for localStorage, one for REST) and sync between them, or use a hybrid indexedDB/REST adapter and write the sync code within the adapter? Can you see any way to avoid implementing push (Web Sockets, ...)?

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  • What is a faster way of merging the values of this Python structure into a single dictionary?

    - by jcoon
    I've refactored how the merged-dictionary (all_classes) below is created, but I'm wondering if it can be more efficient. I have a dictionary of dictionaries, like this: groups_and_classes = {'group_1': {'class_A': [1, 2, 3], 'class_B': [1, 3, 5, 7], 'class_c': [1, 2], # ...many more items like this }, 'group_2': {'class_A': [11, 12, 13], 'class_C': [5, 6, 7, 8, 9] }, # ...and many more items like this } A function creates a new object from groups_and_classes like this (the function to create this is called often): all_classes = {'class_A': [1, 2, 3, 11, 12, 13], 'class_B': [1, 3, 5, 7, 9], 'class_C': [1, 2, 5, 6, 7, 8, 9] } Right now, there is a loop that does this: all_classes = {} for group in groups_and_classes.values(): for c, vals in group.iteritems(): for v in vals: if all_classes.has_key(c): if v not in all_classes[c]: all_classes[c].append(v) else: all_classes[c] = [v] So far, I changed the code to use a set instead of a list since the order of the list doesn't matter and the values need to be unique: all_classes = {} for group in groups_and_classes.values(): for c, vals in group.iteritems(): try: all_classes[c].update(set(vals)) except KeyError: all_classes[c] = set(vals) This is a little nicer, and I didn't have to convert the sets to lists because of how all_classes is used in the code. Question: Is there a more efficient way of creating all_classes (aside from building it at the same time groups_and_classes is built, and changing everywhere this function is called)?

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  • Data synchronization using XMPP

    - by Jason
    Hi: I'm looking for some insight/advice on synchronizing data over XMPP. I've never developed anything for XMPP before so excuse me if some of my questions seem ridiculous. Basically, what I have is a decentralized social network. Each person has it's own Web site (or server) with a unique URI (one domain could host many servers). Each of these servers can have many clients. E.g., a desktop application, mobile application, etc. What I would like to accomplish is near real-time synchronization/communication between client and server, e.g., I update something on my desktop application, I see it change on my Web site. My server and client code is Python. So, I would like to make use of SleekXMPP if possible (it's license seems to have changed to MIT). I was thinking, and here is where I need advice, that each server would register an account at a dedicated XMPP server, e.g., [email protected]. and then I could use different resources for clients [email protected]/client1, [email protected]/client2, etc. If anyone can register any username, then maybe I also need some intermediate service (since it's decentralized, i'm not sure how to control registrations). Another option, I guess, is that each server runs it's own xmpp server. Assuming, that was all worked out, if I want to broadcast messages to all my resources (except the sending one), how do I do that? Do I have to subscribe to myself? This also seems like a good candidate for publish-subscribe, let me know if you think that could work and what the design/flow of that process would be. thanks :)

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  • Writing good tests for Django applications

    - by Ludwik Trammer
    I've never written any tests in my life, but I'd like to start writing tests for my Django projects. I've read some articles about tests and decided to try to write some tests for an extremely simple Django app or a start. The app has two views (a list view, and a detail view) and a model with four fields: class News(models.Model): title = models.CharField(max_length=250) content = models.TextField() pub_date = models.DateTimeField(default=datetime.datetime.now) slug = models.SlugField(unique=True) I would like to show you my tests.py file and ask: Does it make sense? Am I even testing for the right things? Are there best practices I'm not following, and you could point me to? my tests.py (it contains 11 tests): # -*- coding: utf-8 -*- from django.test import TestCase from django.test.client import Client from django.core.urlresolvers import reverse import datetime from someproject.myapp.models import News class viewTest(TestCase): def setUp(self): self.test_title = u'Test title: bareksc' self.test_content = u'This is a content 156' self.test_slug = u'test-title-bareksc' self.test_pub_date = datetime.datetime.today() self.test_item = News.objects.create( title=self.test_title, content=self.test_content, slug=self.test_slug, pub_date=self.test_pub_date, ) client = Client() self.response_detail = client.get(self.test_item.get_absolute_url()) self.response_index = client.get(reverse('the-list-view')) def test_detail_status_code(self): """ HTTP status code for the detail view """ self.failUnlessEqual(self.response_detail.status_code, 200) def test_list_status_code(self): """ HTTP status code for the list view """ self.failUnlessEqual(self.response_index.status_code, 200) def test_list_numer_of_items(self): self.failUnlessEqual(len(self.response_index.context['object_list']), 1) def test_detail_title(self): self.failUnlessEqual(self.response_detail.context['object'].title, self.test_title) def test_list_title(self): self.failUnlessEqual(self.response_index.context['object_list'][0].title, self.test_title) def test_detail_content(self): self.failUnlessEqual(self.response_detail.context['object'].content, self.test_content) def test_list_content(self): self.failUnlessEqual(self.response_index.context['object_list'][0].content, self.test_content) def test_detail_slug(self): self.failUnlessEqual(self.response_detail.context['object'].slug, self.test_slug) def test_list_slug(self): self.failUnlessEqual(self.response_index.context['object_list'][0].slug, self.test_slug) def test_detail_template(self): self.assertContains(self.response_detail, self.test_title) self.assertContains(self.response_detail, self.test_content) def test_list_template(self): self.assertContains(self.response_index, self.test_title)

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  • how do simple SQLAlchemy relationships work?

    - by Carson Myers
    I'm no database expert -- I just know the basics, really. I've picked up SQLAlchemy for a small project, and I'm using the declarative base configuration rather than the "normal" way. This way seems a lot simpler. However, while setting up my database schema, I realized I don't understand some database relationship concepts. If I had a many-to-one relationship before, for example, articles by authors (where each article could be written by only a single author), I would put an author_id field in my articles column. But SQLAlchemy has this ForeignKey object, and a relationship function with a backref kwarg, and I have no idea what any of it MEANS. I'm scared to find out what a many-to-many relationship with an intermediate table looks like (when I need additional data about each relationship). Can someone demystify this for me? Right now I'm setting up to allow openID auth for my application. So I've got this: from __init__ import Base from sqlalchemy.schema import Column from sqlalchemy.types import Integer, String class Users(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) username = Column(String, unique=True) email = Column(String) password = Column(String) salt = Column(String) class OpenID(Base): __tablename__ = 'openid' url = Column(String, primary_key=True) user_id = #? I think the ? should be replaced by Column(Integer, ForeignKey('users.id')), but I'm not sure -- and do I need to put openids = relationship("OpenID", backref="users") in the Users class? Why? What does it do? What is a backref?

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  • How can I visualise a "broken" hierarchical dataset?

    I have a reasonably large datatable structured something like this: StaffNo Grade Direct Boss2 Boss3 Boss4 Boss5 Boss6 ------- ----- ----- ----- ----- ----- ----- ----- 10001 1 10002 10002 10057 10094 10043 10099 10002 2 10057 NULL 10057 10094 10043 10099 10003 1 10004 10004 10057 10094 10043 10099 10004 2 10057 NULL 10057 10094 10043 10099 10057 3 10094 NULL NULL 10094 10043 10099 etc.... i.e. a unique id , their level (grade) in the hierarchy, a record of their bosses ID and the IDs of the supervisors above. (The 2,3,4, etc refers to the boss at that particular grade). The system relies on a strict hierarchy - if you are my boss (/parent) then your boss must be my grandparent. Unfortunately this rule is not enforced within the data model and the data ultimately comes from other systems which don't even know about the rule, let alone observe it. So you and I may share the same boss, but our bosses boss won't be the same. note: I cannot change the data model I cannot fix the data at source. So (for the moment) I have to fix the data once it's in place. Once a fortnight someone will do something which breaks the model and I'll need to modify the procs slightly to resolve. Not ideal, but I'm stuck with this for the next six months. Anyway, specific queries are easy to produce but I find it hard to keep track of the bigger picutre. The application which sits on this runs without complaint regardless but navigating around the system becoming extraordinarily confusing. So my question is: Can anyone recommend a tool (or technique) for generating some kind of "broken tree" diagram in this sort of circumstances? I don't want something that will fix things for me, or attempt statistical analysis but at least something that will give a visual indication of how broken it is at any one time. Note : At the moment this is in a SQL Server database but I'm open to ideas utilising C#, Perl or Python.

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  • SQL Distinct keyword in assignment statement

    - by Brandi
    I have a query that works: DECLARE @ProductID int SET @ProductID = '1234' SELECT DISTINCT TOP 12 a.ProductID FROM A a WHERE a.CategoryID IN (SELECT b.CategoryID FROM B b WHERE b.ProductID = @ProductID) AND a.ProductID != @ProductID It returns a list of 12 product numbers, all unique. I need to store these results in a variable, comma separated, because that's what 3rd party stored procedure needs. So I have this: DECLARE @ProductID int DECLARE @relatedprods varchar(8000) SET @ProductID = '1234' SET @relatedprods = '' SELECT TOP 12 @relatedprods = @relatedprods + CONVERT(VARCHAR(20), a.ProductID) + ', ' FROM A a WHERE a.CategoryID IN (SELECT b.CategoryID FROM B b WHERE B.ProductID = @ProductID) AND a.ProductID != @ProductID SELECT @relatedprods Now, none of these are distinct, but it is returning 12 rows. Now I add the 'distinct' back in, like in the first query: DECLARE @ProductID int DECLARE @relatedprods varchar(8000) SET @ProductID = '1234' SET @relatedprods = '' SELECT DISTINCT TOP 12 @relatedprods = @relatedprods + CONVERT(VARCHAR(20), a.ProductID) + ', ' FROM A a WHERE a.CategoryID IN (SELECT b.CategoryID FROM B b WHERE B.ProductID = @ProductID) AND a.ProductID != @ProductID SELECT @relatedprods Only one product is returned in the comma separated list! Does 'distinct' not work in assignment statements? What did I do wrong? Or is there a way to get around this? Thanks in advance!

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  • Database nesting layout confusion

    - by arzon
    I'm no expert in databases and a beginner in Rails, so here goes something which kinda confuses me... Assuming I have three classes as a sample (note that no effort has been made to address any possible Rails reserved words issue in the sample). class File < ActiveRecord::Base has_many :records, :dependent => :destroy accepts_nested_attributes_for :records, :allow_destroy => true end class Record < ActiveRecord::Base belongs_to :file has_many :users, :dependent => :destroy accepts_nested_attributes_for :users, :allow_destroy => true end class User < ActiveRecord::Base belongs_to :record end Upon entering records, the database contents will appear as such. My issue is that if there are a lot of Files for the same Record, there will be duplicate record names. This will also be true if there will be multiple Records for the same user in the the Users table. I was wondering if there is a better way than this so as to have one or more files point to a single Record entry and one or more Records will point to a single User. BTW, the File names are unique. Files table: id name 1 name1 2 name2 3 name3 4 name4 Records table: id file_id record_name record_type 1 1 ForDaisy1 ... 2 2 ForDonald1 ... 3 3 ForDonald2 ... 4 4 ForDaisy1 ... Users table: id record_id username 1 1 Daisy 2 2 Donald 3 3 Donald 4 4 Daisy Is there any way to optimize the database to prevent duplication of entries, or this should really the correct and proper behavior. I spread out the database into different tables to be able to easily add new columns in the future.

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