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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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  • Counting total sum of each value in one column w.r.t another in Perl

    - by sfactor
    I have tab delimited data with multiple columns. I have OS names in column 31 and data bytes in columns 6 and 7. What I want to do is count the total volume of each unique OS. So, I did something in Perl like this: #!/usr/bin/perl use warnings; my @hhfilelist = glob "*.txt"; my %count = (); for my $f (@hhfilelist) { open F, $f || die "Cannot open $f: $!"; while (<F>) { chomp; my @line = split /\t/; # counting volumes in col 6 and 7 for 31 $count{$line[30]} = $line[5] + $line[6]; } close (F); } my $w = 0; foreach $w (sort keys %count) { print "$w\t$count{$w}\n"; } So, the result would be something like Windows 100000 Linux 5000 Mac OSX 15000 Android 2000 But there seems to be some error in this code because the resulting values I get aren't as expected. What am I doing wrong?

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  • Zend_Db_Select: regrouping conditions in where clause

    - by pvledoux
    Hi, I would like to do something like this: $select = $myTbl->select() ->from('download_log') ->joinLeft(...... etc........ ->joinLeft(...... etc........ ->joinLeft(...... etc........); //Filter all configured bots (Google, Yahoo, etc.) if(isset($this->_config->statistics->bots)){ $bots = explode(',',$this->_config->statistics->bots); foreach ($bots as $bot){ $select = $select->orWhere("user_agent NOT LIKE '%$bot%'"); } } $select = $select->where("download_log.download_log_ts BETWEEN '".$start_date." 00:00:00' AND '".$end_date." 23:59:59'"); But the outputed query is not correct because of the orWhere clauses are not grouped together in a unique AND clause. I would like to know if it is possible to regrouped those OR clauses in a pair of parentheres. My current alternative is the following: //Filter all configured bots (Google, Yahoo, etc.) if(isset($this->_config->statistics->bots)){ $bots = explode(',',$this->_config->statistics->bots); foreach ($bots as $bot){ $stmt .= "user_agent NOT LIKE '%$bot%' OR "; } $stmt = substr($stmt,0,strlen($stmt)-3); //remove the last OR $select = $select->where("($stmt)"); } Thanks!

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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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  • 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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  • jQuery attribute question

    - by Nick Simone
    I'm trying to select a series of divs one at a time. I'm sure theres a better way to do this, but I gave them all unique rels and I'm using the rels to select them one at a time. I want to move them over the width of the div, then animate it dropping down the screen. What I have is: $(document).ready(function(){ var totalbricks = 7; var index = 2; $(".brick").animate({top:"600px"}); while(index < totalbricks) { var postion = 45*index; $(".brick[rel='+index+']").css('left', postion+'px'); $(".brick[rel='+index+']").animate({top:"600px"}); index++; } }); All the divs are in a container div. Jquery docs say, 'Variables can be used using the following syntax: [name='" +MyVar+ "']' What am I doing wrong? Here is the HTML that is being used by the jQuery <body> <div id="container"> <div id="canvas"> <div class="brick" rel="1"> </div> <div class="brick" rel="2"> </div> <div class="brick" rel="3"> </div> <div class="brick" rel="4"> </div> <div class="brick" rel="5"> </div> <div class="brick" rel="6"> </div> <div class="brick" rel="7"> </div> </div> </div> </body>

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  • User preferences using SQL and JavaScript

    - by Shyam
    Hi, I am using Server Side JavaScript - yes, I am actually using Server Side JavaScript. To complexify things even more, I use Oracle as a backend database (10g). With some crazy XSLT and mutant-like HTML generation, I can build really fancy web forms - yes, I am aware of Rails and other likewise frameworks and I choose the path of horror instead. I have no JQuery or other fancy framework at my disposal, just plain ol' JavaScript that should be supported by the underlying engine called Mozilla Rhino. Yes, it is insane and I love it. So, I have a bunch of tables at my disposal and some of them are filled with associative keys that link to values. As I am a people pleaser, I want to add some nifty user-preference driven solutions. My users have all an unique user_id and this user_id is available during the entire session. My initial idea is to have a user preference table, where I have "three" columns: user_id, feature and pref_string. Using a delimiter, such as : or - (haven't thought about a suitable one yet), I could like store a bunch of preferences as a list and store its elements inside an array using the .split-method (similar like the PHP-explode function). The feature column could be like the table name or some identifier for the "feature" i want to link preferences too. I hate hardcoding objects, especially as I want to be able to back these up and reuse this functionality application-wide. Of course I would love better ideas, just keep in mind I cannot just add a library that easily. These preferences could be like "joined" to the table, so I can query it and use its values. I hope it doesn't sounds too complex, because well.. its basically something really simple I need. Thanks!

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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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  • 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 to pass a Dictionary variable to another procedure

    - by salvationishere
    I am developing a C# VS2008/SQL Server website application. I've never used the Dictionary class before, but I am trying to replace my Hashtable with a Dictionary variable. Here is a portion of my aspx.cs code: ... Dictionary<string, string> openWith = new Dictionary<string, string>(); for (int col = 0; col < headers.Length; col++) { @temp = (col + 1); @tempS = @temp.ToString(); @tempT = "@col" + @temp.ToString(); ... openWith.Add(@tempT, headers[col]); } ... for (int r = 0; r < myInputFile.Rows.Count; r++) { resultLabel.Text = ADONET_methods.AppendDataCT(myInputFile, openWith); } But this is giving me a compiler error on this last line: Argument '2': cannot convert from 'System.Collections.Generic.Dictionary' to 'string' How do I pass the entire openWith variable to AppendDataCT? AppendDataCT is the method that calls my SQL stored proc. I want to pass in the whole row where each row has a unique set of values that I want to add to my database table. For example, if each row requires values for cells A, B, and C, then I want to pass these 3 values to AppendDataCT, where all of these values are strings. How do I do this with Dictionary?

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  • Count problem in SQL when I want results from diffrent tabels

    - by Nicklas
    ALTER PROCEDURE GetProducts @CategoryID INT AS SELECT COUNT(tblReview.GroupID) AS ReviewCount, COUNT(tblComment.GroupID) AS CommentCount, Product.GroupID, MAX(Product.ProductID) AS ProductID, AVG(Product.Price) AS Price, MAX (Product.Year) AS Year, MAX (Product.Name) AS Name, AVG(tblReview.Grade) AS Grade FROM tblReview, tblComment, Product WHERE (Product.CategoryID = @CategoryID) GROUP BY Product.GroupID HAVING COUNT(distinct Product.GroupID) = 1 This is what the tabels look like: **Product** |**tblReview** | **tblComment** ProductID | ReviewID | CommentID Name | Description | Description Year | GroupID | GroupID Price | Grade | GroupID GroupID is name_year of a Product, ex Nike_2010. One product can have diffrent sizes for exampel: ProductID | Name | Year | Price | Size | GroupID 1 | Nike | 2010 | 50 | 8 | Nike_2010 2 | Nike | 2010 | 50 | 9 | Nike_2010 3 | Nike | 2010 | 50 | 10 | Nike_2010 4 | Adidas| 2009 | 45 | 8 | Adidas_2009 5 | Adidas| 2009 | 45 | 9 | Adidas_2009 6 | Adidas| 2009 | 45 | 10 | Adidas_2009 I dont get the right count in my tblReview and tblComment. If I add a review to Nike size 8 and I add one review to Nike size 10 I want 2 count results when I list the products with diffrent GroupID. Now I get the same count on Reviews and Comment and both are wrong. I use a datalist to show all the products with diffrent/unique GroupID, I want it to be like this: ______________ | | | Name: Nike | | Year: 2010 | | (All Sizes) | | x Reviews | | x Comments | | x AVG Grade | |______________| All Reviewcounts, Commentcounts and the Average of all products with the same GroupID, the Average works great.

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  • OO vs Simplicity when it comes to user interaction

    - by Oetzi
    Firstly, sorry if this question is rather vague but it's something I'd really like an answer to. As a project over summer while I have some downtime from Uni I am going to build a monopoly game. This question is more about the general idea of the problem however, rather than the specific task I'm trying to carry out. I decided to build this with a bottom up approach, creating just movement around a forty space board and then moving on to interaction with spaces. I realised that I was quite unsure of the best way of proceeding with this and I am torn between two design ideas: Giving every space its own object, all sub-classes of a Space object so the interaction can be defined by the space object itself. I could do this by implementing different land() methods for each type of space. Only giving the Properties and Utilities (as each property has unique features) objects and creating methods for dealing with the buying/renting etc in the main class of the program (or Board as I'm calling it). Spaces like go and super tax could be implemented by a small set of conditionals checking to see if player is on a special space. Option 1 is obviously the OO (and I feel the correct) way of doing things but I'd like to only have to handle user interaction from the programs main class. In other words, I don't want the space objects to be interacting with the player. Why? Errr. A lot of the coding I've done thus far has had this simplicity but I'm not sure if this is a pipe dream or not for larger projects. Should I really be handling user interaction in an entirely separate class? As you can see I am quite confused about this situation. Is there some way round this? And, does anyone have any advice on practical OO design that could help in general?

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  • Trying to find a PHP5 API-based embeddable CMS

    - by StrangeElement
    I've been making the rounds for a CMS that I can use as an API, in a sort of "embedded" mode. I mean by this that I don't want the CMS to do any logic or presentation. I want it to be used as an API, which I can then use within an existing site. I don't want to be tied to the architecture of the CMS. A good example of this is NC-CMS (http://www.nconsulting.ca/nc-cms/). All it needs is an include at the top, then wherever editable content is desired it's only a function call with a unique label. It's also perfect in the sense that it allows to differentiate between small strings (like titles, labels) and texts (which require a rich-text editor). It's the only CMS I found that fits this description, but it is a little too light as it does not handle site structure. I need to be able to allow my client to add pages, choosing an existing template for the layout. A minimal back-end is required. Wordpress also fits some requirements in that it handles only content editing and allows freedom for the themes by letting them call the content where and how they want it. But it is article-based and backwards, in that it embeds sites (as themes) within its structure, rather than being embeddable in sites like NC. It's funny how checking out all the CMS out there, almost all of them claim that most CMS are not self-sufficient, that they do not handle application logic, while (almost) every single on I found with only one exception do so. Many are mostly article-based blog engines, which does not fit my need. I would appreciate any CMS that fits the general description.

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  • [F#] Parallelize code in nested loops

    - by Juliet
    You always hear that functional code is inherently easier to parallelize than non-functional code, so I decided to write a function which does the following: Given a input of strings, total up the number of unique characters for each string. So, given the input [ "aaaaa"; "bbb"; "ccccccc"; "abbbc" ], our method will returns a: 6; b: 6; c: 8. Here's what I've written: (* seq<#seq<char>> -> Map<char,int> *) let wordFrequency input = input |> Seq.fold (fun acc text -> (* This inner loop can be processed on its own thread *) text |> Seq.choose (fun char -> if Char.IsLetter char then Some(char) else None) |> Seq.fold (fun (acc : Map<_,_>) item -> match acc.TryFind(item) with | Some(count) -> acc.Add(item, count + 1) | None -> acc.Add(item, 1)) acc ) Map.empty This code is ideally parallelizable, because each string in input can be processed on its own thread. Its not as straightforward as it looks since the innerloop adds items to a Map shared between all of the inputs. I'd like the inner loop factored out into its own thread, and I don't want to use any mutable state. How would I re-write this function using an Async workflow?

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  • Why this code generates different numbers?

    - by frbry
    Hello, I have this function that creates a unique number for hard-disk and CPU combination. DWORD hw_hash() { char drv[4]; char szNameBuffer[256]; DWORD dwHddUnique; DWORD dwProcessorUnique; DWORD dwUniqueKey; char *sysDrive = getenv ("SystemDrive"); strcpy(drv, sysDrive); drv[2] = '\\'; drv[3] = 0; GetVolumeInformation(drv, szNameBuffer, 256, &dwHddUnique, NULL, NULL, NULL, NULL); SYSTEM_INFO si; GetSystemInfo(&si); dwProcessorUnique = si.dwProcessorType + si.wProcessorArchitecture + si.wProcessorRevision; dwUniqueKey = dwProcessorUnique + dwHddUnique; return dwUniqueKey; } It returns different numbers if I format my hard-disk and install a new Windows. Any ideas, why? Thank you. Edit: OK, Got it: This function returns the volume serial number that the operating system assigns when a hard disk is formatted. To programmatically obtain the hard disk's serial number that the manufacturer assigns, use the Windows Management Instrumentation (WMI) Win32_PhysicalMedia property SerialNumber. I should do more research before posting my problems online. Sorry to bother you, let's keep this here in case anybody else can need it.

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  • MySQL DDL error creating tables

    - by Alexandstein
    I am attempting to create tables for a MySQL database, but I am having some syntactical issues. It would seem that syntax checking is behaving differently between tables for some reason. While I've gotten all the other tables to go through, the table, 'stock' doesn't seem to be working, despite seeming to use the same syntax patterns. CREATE TABLE users ( user_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, username VARCHAR(30) NOT NULL, password CHAR(41) NOT NULL, date_joined DATETIME NOT NULL, funds DOUBLE UNSIGNED NOT NULL, PRIMARY KEY(user_id), UNIQUE KEY(username) ); CREATE TABLE owned_stocks ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, user_id SMALLINT UNSIGNED NOT NULL, paid_price DOUBLE UNSIGNED NOT NULL, quantity MEDIUMINT UNSIGNED NOT NULL, purchase_date DATETIME NOT NULL, PRIMARY KEY(id) ); CREATE TABLE tracking_stocks ( ticker VARCHAR(5) NOT NULL, user_id SMALLINT UNSIGNED NOT NULL, PRIMARY KEY(ticker) ); CREATE TABLE stocks ( ticker VARCHAR(5) NOT NULL, last DOUBLE UNSIGNED NOT NULL, high DOUBLE UNSIGNED NOT NULL, low DOUBLE UNSIGNED NOT NULL, company_name VARCHAR(30) NOT NULL, last_updated INT UNSIGNED NOT NULL, change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, PRIMARY KEY(ticker) ); Am I just missing a really obvious syntactical issue? ERROR: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, last DOUBLE' at line 4

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  • Substrings, timer and LED lights, as3

    - by VideoDnd
    How would I sync my timer with my LED lights? I don't understand how to to set up the strings and conditions, so that they are unique to each number space. Need a condition and values for each blinker var condition:Number = 5; if(condition==5){ blink.visible = !blink.visible; //blink_.visible = !box.visible; //blink__.visible = !box.visible; } } Complete code //MY TIMER var timer:Timer = new Timer(100); //INTEGER VALUES var count:int = 0; var fcount:int = 0; var oldcount:int = 0; //FORMATTING STRING function formatCount(i:int):String { var fraction:int = i % 100; var whole:int = i / 100; return ("00" + whole).substr(-2, 2) + "." + (fraction < 10 ? "0" + fraction : fraction); } //START TIMER timer.start(); timer.addEventListener(TimerEvent.TIMER, condition); //ANIMATION function condition(event:TimerEvent):void{ count++; fcount=int(count) var toText:String = formatCount(fcount); dec.text = toText.substr(4, 1); decimal.text = toText.substr(3, 1); ones.text = toText.substr(1, 1); //LED LIGHTS var condition:Number = 5; if(condition==5){ blink.visible = !blink.visible; //blink_.visible = !box.visible; //blink__.visible = !box.visible; } }

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  • Understanding MongoDB (and NoSQL in general) and how to make the best use of it

    - by Earlz
    Hello, I am beginning to think that my next project I am wanting to do would work better with a NoSQL solution. The project would either involve a ton of 2-column tables or a ton of dynamic queries with dynamically generated columns in a traditional SQL database. So I feel a NoSQL database would be much cleaner. I'm looking at MongoDB and it looks pretty promising. Anyway, I'm attempting to make sense of it all. Also, I will be using MongoMapper in Ruby. Anyway though, I'm confused as to how to layout things in such a freeform database. I've read http://stackoverflow.com/questions/2170152/nosql-best-practices and the answer there says that normalization is usually bad in a NoSQL DB. So how would be the best way of laying out say a simple blog with users, posts, and comments? My natural thought was to have three collections for each and then link them by a unique ID. But this apparently is wrong? So, what are some of the ways to lay out such a thing? My concern with the answer given in the other question is, what if the author's name changed? You'd have to go through updating a ton of posts and comments. But is this an okay thing to do with NoSQL?

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  • ASP.NET MVC Newbie: why isn't my model available when creating a strongly-typed view?

    - by Rax Olgud
    I'm starting with ASP.NET MVC, and working with NerdDinner as reference. I did the following: Created a new project Added a couple of tables Created LINQ to SQL for them Created a new controller My Models directory now contains MyModel.dbml, under which I have MyModel.designer.cs, that contains classes for models relating to both of my tables (let's call them Categories and Products). Now, under my new controller, I would like to create a strongly typed view. So for example I have the following code in my controller (for my application I must work by name, and the "Name" field is unique): public ActionResult Details(string name) { MyModelDataContext db = new MyModelDataContext(); Product user = db.Products.Single(t => t.Name == name); return View(user); } I would like to create a strongly-typed view. So I right-click the line "return View(user)", and choose "Add View...". I click "Create a strongly-typed view". When I click the dropdown of "View data class", I don't see my models, but only: MyProject.Controllers.AccountMembershipService MyProject.Controllers.FormsAuthenticationService What am I missing?

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  • JDO, GAE: Load object group by child's key

    - by tiex
    I have owned one-to-many relationship between two objects: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class AccessInfo { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private com.google.appengine.api.datastore.Key keyInternal; ... @Persistent private PollInfo currentState; public AccessInfo(){} public AccessInfo(String key, String voter, PollInfo currentState) { this.voter = voter; this.currentState = currentState; setKey(key); // this key is unique in whole systme } public void setKey(String key) { this.keyInternal = KeyFactory.createKey( AccessInfo.class.getSimpleName(), key); } public String getKey() { return this.keyInternal.getName(); } and @PersistenceCapable(identityType = IdentityType.APPLICATION) public class PollInfo { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key key; @Persistent(mappedBy = "currentState") private List<AccessInfo> accesses; ... I created an instance of class PollInfo and make it persistence. It is ok. But then I want to load this group by AccessInfo key, and I am getting exception NucleusObjectNotFoundException. Is it possible to load a group by child's key?

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  • How do I join three tables with SQLalchemy and keeping all of the columns in one of the tables?

    - by jimka
    So, I have three tables: The class defenitions: engine = create_engine('sqlite://test.db', echo=False) SQLSession = sessionmaker(bind=engine) Base = declarative_base() class Channel(Base): __tablename__ = 'channel' id = Column(Integer, primary_key = True) title = Column(String) description = Column(String) link = Column(String) pubDate = Column(DateTime) class User(Base): __tablename__ = 'user' id = Column(Integer, primary_key = True) username = Column(String) password = Column(String) sessionId = Column(String) class Subscription(Base): __tablename__ = 'subscription' userId = Column(Integer, ForeignKey('user.id'), primary_key=True) channelId = Column(Integer, ForeignKey('channel.id'), primary_key=True) And the SQL commands that are executed to create them: CREATE TABLE subscription ( "userId" INTEGER NOT NULL, "channelId" INTEGER NOT NULL, PRIMARY KEY ("userId", "channelId"), FOREIGN KEY("userId") REFERENCES user (id), FOREIGN KEY("channelId") REFERENCES channel (id) ); CREATE TABLE user ( id INTEGER NOT NULL, username VARCHAR, password VARCHAR, "sessionId" VARCHAR, PRIMARY KEY (id) ); CREATE TABLE channel ( id INTEGER NOT NULL, title VARCHAR, description VARCHAR, link VARCHAR, "pubDate" TIMESTAMP, PRIMARY KEY (id) ); NOTE: I know user.username should be unique, need to fix that, and I'm not sure why SQLalchemy creates some row names with the double-quotes. And I'm trying to come up with a way to retrieve all of the channels, as well as an indication on what channels one particular user (identified by user.sessionId together with user.id) has a subscription on. For example, say we have four channels: channel1, channel2, channel3, channel4; a user: user1; who has a subscription on channel1 and channel4. The query for user1 would return something like: channel.id | channel.title | subscribed --------------------------------------- 1 channel1 True 2 channel2 False 3 channel3 False 4 channel4 True This is a best-case result, but since I have absolutely no clue as how to accomplish the subscribed column, I've been instead trying to get the particular users id in the rows where the user has a subscription and where a subscription is missing, just leave it blank. The database engine that I'm using together with SQLalchemy atm. is sqlite3 I've been scratching my head over this for two days now, I've no problem joining together all three by way of the subscription table but then all of the channels where the user does not have a subscription gets omitted. I hope I've managed to describe my problem sufficiently, thanks in advance.

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  • Understanding MongoDB(and NoSQL in general) and How to make the best use of it

    - by Earlz
    Hello, I am beginning to think that my next project I am wanting to do would work better with a NoSQL solution. The project would either involve a ton of 2-column tables or a ton of dynamic queries with dynamically generated columns in a traditional SQL database. So I feel a NoSQL database would be much cleaner. I'm looking at MongoDB and it looks pretty promising. Anyway, I'm attempting to make sense of it all. Also, I will be using MongoMapper in Ruby. Anyway though, I'm confused as to how to layout things in such a freeform database. I've read http://stackoverflow.com/questions/2170152/nosql-best-practices and the answer there says that normalization is usually bad in a NoSQL DB. So how would be the best way of laying out say a simple blog with users, posts, and comments? My natural thought was to have 3 collections for each and then link them by a unique ID. But this apparently is wrong? So, what are some of the ways to lay out such a thing? My concern with the answer given in the other question is what if the author's name changed. You'd have to go through updating a ton of posts and comments. But is this an ok thing to do with NoSQL?

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  • What's the most efficient query?

    - by Aaron Carlino
    I have a table named Projects that has the following relationships: has many Contributions has many Payments In my result set, I need the following aggregate values: Number of unique contributors (DonorID on the Contribution table) Total contributed (SUM of Amount on Contribution table) Total paid (SUM of PaymentAmount on Payment table) Because there are so many aggregate functions and multiple joins, it gets messy do use standard aggregate functions the the GROUP BY clause. I also need the ability to sort and filter these fields. So I've come up with two options: Using subqueries: SELECT Project.ID AS PROJECT_ID, (SELECT SUM(PaymentAmount) FROM Payment WHERE ProjectID = PROJECT_ID) AS TotalPaidBack, (SELECT COUNT(DISTINCT DonorID) FROM Contribution WHERE RecipientID = PROJECT_ID) AS ContributorCount, (SELECT SUM(Amount) FROM Contribution WHERE RecipientID = PROJECT_ID) AS TotalReceived FROM Project; Using a temporary table: DROP TABLE IF EXISTS Project_Temp; CREATE TEMPORARY TABLE Project_Temp (project_id INT NOT NULL, total_payments INT, total_donors INT, total_received INT, PRIMARY KEY(project_id)) ENGINE=MEMORY; INSERT INTO Project_Temp (project_id,total_payments) SELECT `Project`.ID, IFNULL(SUM(PaymentAmount),0) FROM `Project` LEFT JOIN `Payment` ON ProjectID = `Project`.ID GROUP BY 1; INSERT INTO Project_Temp (project_id,total_donors,total_received) SELECT `Project`.ID, IFNULL(COUNT(DISTINCT DonorID),0), IFNULL(SUM(Amount),0) FROM `Project` LEFT JOIN `Contribution` ON RecipientID = `Project`.ID GROUP BY 1 ON DUPLICATE KEY UPDATE total_donors = VALUES(total_donors), total_received = VALUES(total_received); SELECT * FROM Project_Temp; Tests for both are pretty comparable, in the 0.7 - 0.8 seconds range with 1,000 rows. But I'm really concerned about scalability, and I don't want to have to re-engineer everything as my tables grow. What's the best approach?

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  • iPad width in viewport settings overflowing past device width

    - by user1327771
    I am at my wit's end here, and I beseech the fine folks here at stackoverflow for help. I am working on a design for a blog for a friend of mine, and I'm working in HTML5. I am trying to get the width of the page to span the width of an iPad. So, in my document head, I have the following: <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0"> Now, if you go to the index page, on an iPad, it looks just fine. The width of the page spans the width of the iPad in portrait mode, as I expect it to: http://www.alanreuterart.com/femmegamers/index.html It also looks fine on any individual blog posts as well. However, on the "about" and "join" pages, the width does not do this. It's actually overflowing past the length of the iPad to the right. View the following page on an iPad to see what I mean: http://www.alanreuterart.com/femmegamers/about.html I've tried everything. I cannot, for the life of me, figure out how to get it those two pages to correctly span the device width of the iPad. One important note, though: before anyone tells me to set my viewport width to 960, I cannot do that because the pages have media queries in them to convert to a mobile layout for the iPhone and other mobile phones. (I am not making a special unique layout for the iPad.) Can ANYONE help out here? Thanks in advance! —Me.

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  • volatile keyword seems to be useless?

    - by Finbarr
    import java.util.concurrent.CountDownLatch; import java.util.concurrent.atomic.AtomicInteger; public class Main implements Runnable { private final CountDownLatch cdl1 = new CountDownLatch(NUM_THREADS); private volatile int bar = 0; private AtomicInteger count = new AtomicInteger(0); private static final int NUM_THREADS = 25; public static void main(String[] args) { Main main = new Main(); for(int i = 0; i < NUM_THREADS; i++) new Thread(main).start(); } public void run() { int i = count.incrementAndGet(); cdl1.countDown(); try { cdl1.await(); } catch (InterruptedException e1) { e1.printStackTrace(); } bar = i; if(bar != i) System.out.println("Bar not equal to i"); else System.out.println("Bar equal to i"); } } Each Thread enters the run method and acquires a unique, thread confined, int variable i by getting a value from the AtomicInteger called count. Each Thread then awaits the CountDownLatch called cdl1 (when the last Thread reaches the latch, all Threads are released). When the latch is released each thread attempts to assign their confined i value to the shared, volatile, int called bar. I would expect every Thread except one to print out "Bar not equal to i", but every Thread prints "Bar equal to i". Eh, wtf does volatile actually do if not this?

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