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  • WPF MVVM Cancel Edit

    - by terkri
    How can I implement cancelation of editing an object using MVVM. For example: I have a list of customers. I choose one customer an click the button "Edit", a dialog window(DataContext is binded to CustomerViewModel) opens and I start editing customer's fields. And then I decide to cancel editing, but the fields of the customer have been already changed, so how can I return a customer to its previous state in MVVM?

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  • Any way to allow classes implementing IEntity and downcast to have operator == comparisons?

    - by George Mauer
    Basically here's the issue. All entities in my system are identified by their type and their id. new Customer() { Id = 1} == new Customer() {Id = 1}; new Customer() { Id = 1} != new Customer() {Id = 2}; new Customer() { Id = 1} != new Product() {Id = 1}; Pretty standard scenario. Since all Entities have an Id I define an interface for all entities. public interface IEntity { int Id { get; set;} } And to simplify creation of entities I make public abstract class BaseEntity<T> : where T : IEntity { int Id { get; set;} public static bool operator ==(BaseEntity<T> e1, BaseEntity<T> e2) { if (object.ReferenceEquals(null, e1)) return false; return e1.Equals(e2); } public static bool operator !=(BaseEntity<T> e1, BaseEntity<T> e2) { return !(e1 == e2); } } where Customer and Product are something like public class Customer : BaseEntity<Customer>, IEntity {} public class Product : BaseEntity<Product>, IEntity {} I think this is hunky dory. I think all I have to do is override Equals in each entity (if I'm super clever, I can even override it only once in the BaseEntity) and everything with work. So now I'm expanding my test coverage and find that its not quite so simple! First of all , when downcasting to IEntity and using == the BaseEntity< override is not used. So what's the solution? Is there something else I can do? If not, this is seriously annoying. Upadate It would seem that there is something wrong with my tests - or rather with comparing on generics. Check this out [Test] public void when_created_manually_non_generic() { // PASSES! var e1 = new Terminal() {Id = 1}; var e2 = new Terminal() {Id = 1}; Assert.IsTrue(e1 == e2); } [Test] public void when_created_manually_generic() { // FAILS! GenericCompare(new Terminal() { Id = 1 }, new Terminal() { Id = 1 }); } private void GenericCompare<T>(T e1, T e2) where T : class, IEntity { Assert.IsTrue(e1 == e2); } Whats going on here? This is not as big a problem as I was afraid, but is still quite annoying and a completely unintuitive way for the language to behave. Update Update Ah I get it, the generic implicitly downcasts to IEntity for some reason. I stand by this being unintuitive and potentially problematic for my Domain's consumers as they need to remember that anything happening within a generic method or class needs to be compared with Equals()

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  • Assigining ID vs object - linq to sql

    - by jess
    Say, I have an entity Customer which has relationship with city,order etc.Now,when I am adding a customer object,should I assign customer.cityid, or customer.city? Now,from form I get cityid from dropdown,to assign city object,I will have to make a query using id selected.

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  • Circular database relationships. Good, Bad, Exceptions?

    - by jim
    I have been putting off developing this part of my app for sometime purely because I want to do this in a circular way but get the feeling its a bad idea from what I remember my lecturers telling me back in school. I have a design for an order system, ignoring the everything that doesn't pertain to this example I'm left with: CreditCard Customer Order I want it so that, Customers can have credit cards (0-n) Customers have orders (1-n) Orders have one customer(1-1) Orders have one credit card(1-1) Credit cards can have one customer(1-1) (unique ids so we can ignore uniqueness of cc number, husband/wife may share cc instances ect) Basically the last part is where the issue shows up, sometimes credit cards are declined and they wish to use a different one, this needs to update which their 'current' card is but this can only change the current card used for that order, not the other orders the customer may have on disk. Effectively this creates a circular design between the three tables. Possible solutions: Either Create the circular design, give references: cc ref to order, customer ref to cc customer ref to order or customer ref to cc customer ref to order create new table that references all three table ids and put unique on the order so that only one cc may be current to that order at any time Essentially both model the same design but translate differently, I am liking the latter option best at this point in time because it seems less circular and more central. (If that even makes sense) My questions are, What if any are the pros and cons of each? What is the pitfalls of circular relationships/dependancies? Is this a valid exception to the rule? Is there any reason I should pick the former over the latter? Thanks and let me know if there is anything you need clarified/explained. --Update/Edit-- I have noticed an error in the requirements I stated. Basically dropped the ball when trying to simplify things for SO. There is another table there for Payments which adds another layer. The catch, Orders can have multiple payments, with the possibility of using different credit cards. (if you really want to know even other forms of payment). Stating this here because I think the underlying issue is still the same and this only really adds another layer of complexity.

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  • Rails only returns blank page

    - by user2793027
    I am new to Ruby on Rails and am trying to find all the orders for a given customer and then search through their order and total it all up. However when I try and test the page I only get a blank page, can anyone tell me why that might be? Also I am running Rails v. 2.3.14 <% # custdisplay.html.erb.rb %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head profile="http://gmpg.org/xfn/11"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> </head> <body> <% # get the customer data from the customer table @custdata = Customer.find(@data) @orderinfo = Order.find(:all, :conditions => ["customer_id = ?",@custdata.id]) for i in [email protected] @total[i] = 0 @orderparts = Orderline.find(:all, :conditions => ["id = ?", @orderinfo[i].id]) for j in [email protected] @total[j] += @orderparts[i].quantity * @orderparts[i].price end end #for each quanity need to add up the part if @ordertotals.length > 0 %> <h1>customer data for customer: <%=@data %></h1> <table border=1> <tr> <td>Order Number</td> <td>Order Date</td> <td>Cost of Order</td> </tr> <% # for each customer who has this sales rep # display each customer in a row for @orderinfo in @ordertotals %> <tr> <td><%[email protected]%></td> <td><%[email protected]_date%></td> <td><%[email protected]%></td> </tr> <% end %> </table> <% else # no customers with this sales rep %> <h1>NO CUSTOMERS FOR SALES REP <%=@salesrepcust%></h1> <% end %>

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  • SQL: HAVING clause

    - by Craig Johnston
    See the following SQL statement: SELECT datediff("d", MAX(invoice.date), Now) As Date_Diff, MAX(invoice.date) AS max_invoice_date, customer.number AS customer_number FROM invoice INNER JOIN customer ON invoice.customer_number = customer.number GROUP BY customer.number If the the following was added: HAVING datediff("d", MAX(invoice.date), Now) > 365 would this simply exclude rows with Date_Diff <= 365? What should be the effect of the HAVING clause here?

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  • How to make the firewall popup a warning to my http server?

    - by user497032
    I integrated a small http server in my software distribution, so when my customer installs my software, a http server is also installed on his computer, he can visit the http server from his LAN (local network). The problem is that my customer has to manually add my software into the firewall's trusted applications list, I want the firewall to AUTOMATICALLY popup warning to let my customer choose yes/no to add my software into trusted applications list when my customer visit the small http server from LAN at first time. Any suggestions?

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  • Rails find through association

    - by yogi
    class Customer < ActiveRecord::Base has_one :address, :foreign_key => "customerid" end class Address < ActiveRecord::Base belongs_to :customer, :foreign_key => "customerid" end How do I find records in customer that do not have customerid in address table? in SQL i'd do select * from customer a, address b where a.customerid <> b.customerid

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  • SQL Alter: add multiple FKs?

    - by acidzombie24
    From here ALTER TABLE ORDERS ADD FOREIGN KEY (customer_sid) REFERENCES CUSTOMER(SID); How do i add several keys with SQL Server? is it something like the below? (I cant test ATM and unfortunately i have no way to test queries unless i run it through code) ALTER TABLE ORDERS ADD FOREIGN KEY (customer_sid) REFERENCES CUSTOMER(SID), ADD FOREIGN KEY (customer_sid2) REFERENCES CUSTOMER(SID2); or is it like ALTER TABLE ORDERS ADD FOREIGN KEY (customer_sid, customer_sid2) REFERENCES CUSTOMER(SID, SID2)

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  • Customer site is out of IP addresses, they want to go from /24 to /12 netmask... Bad idea?

    - by ewwhite
    One of my client sites called to ask me to change the subnet masks of the Linux servers I manage there while they re-IP/change the netmask of their network based on a 10.0.0.x scheme. "Can you change the server netmasks from 255.255.255.0 to 255.240.0.0?" You mean, 255.255.240.0? "No, 255.240.0.0." Are you sure you need that many IP addresses? "Yeah, we never want to run out of IP addresses." A quick check against the Subnet Cheat Sheet shows: a 255.255.255.0 netmask, a /24 provides 256 hosts. It's clear to see that an organization can exhaust that number of IP addresses. a 255.240.0.0 netmask, a /12 provides 1,048,576 hosts. This is a small < 200-user site. I doubt that they'd allocate more than 400 IP addresses. I suggested something that provides fewer hosts, like a /22 or /21 (1024 and 2048 hosts, respectively), but was unable to give a specific reason against using the /12 subnet. Is there anything this customer should be concerned about? Are there any specific reasons they shouldn't use such an incredibly large mask in their environment?

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  • Who Makes a Good Product Owner

    - by Robert May
    In general, the best product owners are those that care passionately about the customer of the product.  Note that I didn’t say about the product itself.  Actually, people that only care about the product, generally do not make good product owners.  Products only matter in relationship to their customers.  If a product doesn’t provide value to the customer, then the product has no value, no matter what a person might think of the product, and no matter what cool technologies exist inside of the product. A good product owner is also a good negotiator.  They recognize that many different priorities exist inside of a corporation, but that there can be only one list that developers work from.  A good product owner recognizes that its their job to help others around them prioritize (perhaps with a Product Council), but also understand that they alone have the final say about priorities and are willing to make the tough decisions required.  Deciding the priority between two perfectly valid stories is very difficult, especially when the stories are from two different departments! A good product owner is deeply interested in helping the team be successful.  They don’t seek to control the team, but instead seek to understand what the team can do and then work with the team to get the best product possible for the Customer.  A good product owner is never denigrating to team members, ever.  They recognize that such behavior would damage the trust that needs to be present between team members and product owners and will avoid it at all costs. In general, technical people (i.e. former or current developers) make poor product owners.  In their minds, they can’t separate implementation details from user functionality, so their stories end up sounding like implementation details.  For example, “The user enters their username on the password screen” is something that a technical product owner would write.  The proper wording for that story is “A user supplies the system with their credentials.”  Because technical people think different from the rest of the population, they are generally not a good fit. A good product owner is also a good writer.  Writing good stories demands good writing.  The art of persuasion, descriptiveness and just general good grammar are all required.  A good Product Owner must also be well spoken, since most of what will be conveyed will be conveyed with the spoken word, not just written word. A good product owner is a “People Person.”  They like talking to people and are very patient.  They don’t mind having questions repeated or fielding many questions, because they want to make sure that the ideas they’re conveying are properly understood so the customer gets the best product possible.  They are happy to answer any questions a team member may have and invite feedback and criticism of designs and stories, since they want a good product.  They really have little ego that gets in the way of building a great product. All of these qualities can be hard to find, but if you look close enough, you’ll find the right person in your organization.  Product owners can be found anywhere, not just in upper management.  Some of the best product owners are those that are very close to the customer.  In fact, check your customer support staff.  I’d bet that several great product owners are lurking there. Final note about what makes a good product owner.  You’re probably NOT going to find a good product owner in a manager, especially if they consider themselves a “Manager.”  Product owners don’t manage anything but the backlog, so be especially careful if the person you’re selecting for Product Owner is a manager. Up Next, “Messing with the Team.” Technorati Tags: Scrum,Product Owner

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  • Impressions of Pivotal Tracker

    Pivotal Tracker is a free, online agile project management system. Ive been using it recently to better communicate to customers about the current state of our project. In Pivotal Tracker, the unit of work is a story and stories are arranged into iterations or delivery cycles. Stories can be any level of granularity you want, but the idea is to use stories to communicate clearly to customers, so you dont want to write a novel. You especially dont want to write a list of detailed programming tasks. A good story for a point of sale system might be: Allow managers to override the price of an item while ringing up a customer. A less useful story: Script out the process of adding a manager flag to the user table and stage that script into the deploy directory. Stories are estimated using a point scale, by default 1, 2 or 3. Iterations are then automatically laid out by combining enough tasks to fill the point total for that period of time. You have to start with a guess on how many points your team can do in an iteration, then adjust with real data as you complete iterations. This is basic agile methodology, but where Pivotal Tracker adds value is that it automatically and graphically lays out iterations for you on your project site. This makes communication and planning easy. Compiling release notes is no longer painful as it has been clear from the outset what work is going on. While I much prefer Pivotal Trackers customer facing interface over what we used previously (TFS), I see a couple of gaps. First, I have not able to make much headway with the reporting tools. Despite my complaints about TFS, it can produce some nice reports. Second, its not clear where if at all, Id keep track of purely internal tasks. Im talking about server maintenance, cleaning up source control, checking back on some code which you never quite felt right about. Theres no purpose in cluttering up an iteration backlog with these items, but if you dont track them, you lose them. Im not sure what a good answer for that is. One gap I thought Id see, which I dont, is more granular dev tasks. If Im implementing a story, Ill write out the steps and track my progress, but really, those steps arent useful to anybody but me. The only time Ive found that level of detail really useful is when my tasks are defined at too high a level anyway or when Im working with someone who needs more coaching and might not be able to finish a story in time without some scaffolding to get them going. You can learn more about Pivotal Tracker at: http://www.pivotaltracker.com/learnmore.   --- Relevant Links --- A good intro to stories: http://www.agilemodeling.com/artifacts/userStory.htmDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Book Review (Book 12) - 20 Master Plots

    - by BuckWoody
    This is a continuation of the books I challenged myself to read to help my career - one a month, for a year. You can read my first book review here, and the entire list is here. The book I chose for May 2012 was:20 Master Plots by Ronald B. Tobias. This is my final book review - at least for this year. I'll explain what I've learned in this book in particular, and in the last twelve months in general. Why I chose this book: Stories and themes are part of software, presenting, and working in teams. This book claims there are only 20 plots, ever. I wanted to find out. What I learned: Probably my most favorite read of the year. Deceptively small, amazingly insightful. The premise is that there are only a few "base" themes, and that once you learn them you can put together an interesting set of stories on most any topic. Yes, the author admits that this number has been different throughout history - some have said 50, others 14, and still others claim only one or two basic plots. This doesn't change the fact that you can build very complex stories from a simple set of circumstances and characters. Be warned - if you read this book it takes away much of the wonder from almost every movie or book you'll read from here on! I loved it. My favorite part is that the author gives you exercises to build stories, right from the start. I've actually used these as the start of a meeting to foster creativity. Amazing stuff. One of my favorite sections of the book deals with plot and story. Plot: The king died, and the queen died. Story: The king died, and the queen died of heartbreak. Add one or two words, and you have the essence of storytelling. A highly recommended read, for all folks of all ages. You'll like it, your spouse will like it, and your kids will like it. I learned to be a better storyteller, and it helped me understand that plots and stories are not just things in books - they are a direct reflection of human nature. That makes me a better manager of myself and others.   And this is the last of the reviews - at least for this year. I probably won't post many more book reviews here, but I will keep up the practice. As a reminder, the goal was to select 12 books that will help you reach your career goals. They don't have to be technical, or even apply directly to your job - but they do need to be books that you mindfully select as getting you closer to what you want to be. Each month, jot down what you learned from the work. And see if it doesn't in fact get you closer to your goals. These readings helped me - I got a promotion this year, and I attribute at least some of that to the things I learned.

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  • Book Review (Book 12) - 20 Master Plots

    - by BuckWoody
    This is a continuation of the books I challenged myself to read to help my career - one a month, for a year. You can read my first book review here, and the entire list is here. The book I chose for May 2012 was:20 Master Plots by Ronald B. Tobias. This is my final book review - at least for this year. I'll explain what I've learned in this book in particular, and in the last twelve months in general. Why I chose this book: Stories and themes are part of software, presenting, and working in teams. This book claims there are only 20 plots, ever. I wanted to find out. What I learned: Probably my most favorite read of the year. Deceptively small, amazingly insightful. The premise is that there are only a few "base" themes, and that once you learn them you can put together an interesting set of stories on most any topic. Yes, the author admits that this number has been different throughout history - some have said 50, others 14, and still others claim only one or two basic plots. This doesn't change the fact that you can build very complex stories from a simple set of circumstances and characters. Be warned - if you read this book it takes away much of the wonder from almost every movie or book you'll read from here on! I loved it. My favorite part is that the author gives you exercises to build stories, right from the start. I've actually used these as the start of a meeting to foster creativity. Amazing stuff. One of my favorite sections of the book deals with plot and story. Plot: The king died, and the queen died. Story: The king died, and the queen died of heartbreak. Add one or two words, and you have the essence of storytelling. A highly recommended read, for all folks of all ages. You'll like it, your spouse will like it, and your kids will like it. I learned to be a better storyteller, and it helped me understand that plots and stories are not just things in books - they are a direct reflection of human nature. That makes me a better manager of myself and others.   And this is the last of the reviews - at least for this year. I probably won't post many more book reviews here, but I will keep up the practice. As a reminder, the goal was to select 12 books that will help you reach your career goals. They don't have to be technical, or even apply directly to your job - but they do need to be books that you mindfully select as getting you closer to what you want to be. Each month, jot down what you learned from the work. And see if it doesn't in fact get you closer to your goals. These readings helped me - I got a promotion this year, and I attribute at least some of that to the things I learned.

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  • Django manager for _set in model

    - by Daniel Johansson
    Hello, I'm in the progress of learning Django at the moment but I can't figure out how to solve this problem on my own. I'm reading the book Developers Library - Python Web Development With Django and in one chapter you build a simple CMS system with two models (Story and Category), some generic and custom views together with templates for the views. The book only contains code for listing stories, story details and search. I wanted to expand on that and build a page with nested lists for categories and stories. - Category1 -- Story1 -- Story2 - Category2 - Story3 etc. I managed to figure out how to add my own generic object_list view for the category listing. My problem is that the Story model have STATUS_CHOICES if the Story is public or not and a custom manager that'll only fetch the public Stories per default. I can't figure out how to tell my generic Category list view to also use a custom manager and only fetch the public Stories. Everything works except that small problem. I'm able to create a list for all categories with a sub list for all stories in that category on a single page, the only problem is that the list contains non public Stories. I don't know if I'm on the right track here. My urls.py contains a generic view that fetches all Category objects and in my template I'm using the *category.story_set.all* to get all Story objects for that category, wich I then loop over. I think it would be possible to add a if statement in the template and use the VIEWABLE_STATUS from my model file to check if it should be listed or not. The problem with that solution is that it's not very DRY compatible. Is it possible to add some kind of manager for the Category model too that only will fetch in public Story objects when using the story_set on a category? Or is this the wrong way to attack my problem? Related code urls.py (only category list view): urlpatterns += patterns('django.views.generic.list_detail', url(r'^categories/$', 'object_list', {'queryset': Category.objects.all(), 'template_object_name': 'category' }, name='cms-categories'), models.py: from markdown import markdown import datetime from django.db import models from django.db.models import permalink from django.contrib.auth.models import User VIEWABLE_STATUS = [3, 4] class ViewableManager(models.Manager): def get_query_set(self): default_queryset = super(ViewableManager, self).get_query_set() return default_queryset.filter(status__in=VIEWABLE_STATUS) class Category(models.Model): """A content category""" label = models.CharField(blank=True, max_length=50) slug = models.SlugField() class Meta: verbose_name_plural = "categories" def __unicode__(self): return self.label @permalink def get_absolute_url(self): return ('cms-category', (), {'slug': self.slug}) class Story(models.Model): """A hunk of content for our site, generally corresponding to a page""" STATUS_CHOICES = ( (1, "Needs Edit"), (2, "Needs Approval"), (3, "Published"), (4, "Archived"), ) title = models.CharField(max_length=100) slug = models.SlugField() category = models.ForeignKey(Category) markdown_content = models.TextField() html_content = models.TextField(editable=False) owner = models.ForeignKey(User) status = models.IntegerField(choices=STATUS_CHOICES, default=1) created = models.DateTimeField(default=datetime.datetime.now) modified = models.DateTimeField(default=datetime.datetime.now) class Meta: ordering = ['modified'] verbose_name_plural = "stories" def __unicode__(self): return self.title @permalink def get_absolute_url(self): return ("cms-story", (), {'slug': self.slug}) def save(self): self.html_content = markdown(self.markdown_content) self.modified = datetime.datetime.now() super(Story, self).save() admin_objects = models.Manager() objects = ViewableManager() category_list.html (related template): {% extends "cms/base.html" %} {% block content %} <h1>Categories</h1> {% if category_list %} <ul id="category-list"> {% for category in category_list %} <li><a href="{{ category.get_absolute_url }}">{{ category.label }}</a></li> {% if category.story_set %} <ul> {% for story in category.story_set.all %} <li><a href="{{ story.get_absolute_url }}">{{ story.title }}</a></li> {% endfor %} </ul> {% endif %} {% endfor %} </ul> {% else %} <p> Sorry, no categories at the moment. </p> {% endif %} {% endblock %}

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  • ASP.net roles and Projects

    - by Zyphrax
    EDIT - Rewrote my original question to give a bit more information Background info At my work I'm working on a ASP.Net web application for our customers. In our implementation we use technologies like Forms authentication with MembershipProviders and RoleProviders. All went well until I ran into some difficulties with configuring the roles, because the roles aren't system-wide, but related to the customer accounts and projects. I can't name our exact setup/formula, because I think our company wouldn't approve that... What's a customer / project? Our company provides management information for our customers on a yearly (or other interval) basis. In our systems a customer/contract consists of: one Account: information about the Company per Account, one or more Products: the bundle of management information we'll provide per Product, one or more Measurements: a period of time, in which we gather and report the data Extranet site setup Eventually we want all customers to be able to access their management information with our online system. The extranet consists of two sites: Company site: provides an overview of Account information and the Products Measurement site: after selecting a Measurement, detailed information on that period of time The measurement site is the most interesting part of the extranet. We will create submodules for new overviews, reports, managing and maintaining resources that are important for the research. Our Visual Studio solution consists of a number of projects. One web application named Portal for the basis. The sites and modules are virtual directories within that application (makes it easier to share MasterPages among things). What kind of roles? The following users (read: roles) will be using the system: Admins: development users :) (not customer related, full access) Employees: employees of our company (not customer related, full access) Customer SuperUser: top level managers (full access to their account/measurement) Customer ContactPerson: primary contact (full access to their measurement(s)) Customer Manager: a department manager (limited access, specific data of a measurement) What about ASP.Net users? The system will have many ASP.Net users, let's focus on the customer users: Users are not shared between Accounts SuperUser X automatically has access to all (and new) measurements User Y could be Primary contact for Measurement 1, but have no role for Measurement 2 User Y could be Primary contact for Measurement 1, but have a Manager role for Measurement 2 The department managers are many individual users (per Measurement), if Manager Z had a login for Measurement 1, we would like to use that login again if he participates in Measurement 2. URL structure These are typical urls in our application: http://host/login - the login screen http://host/project - the account/product overview screen (measurement selection) http://host/project/1000 - measurement (id:1000) details http://host/project/1000/planning - planning overview (for primary contact/superuser) http://host/project/1000/reports - report downloads (manager department X can only access report X) We will also create a document url, where you can request a specific document by it's GUID. The system will have to check if the user has rights to the document. The document is related to a Measurement, the User or specific roles have specific rights to the document. What's the problem? (finally ;)) Roles aren't enough to determine what a user is allowed to see/access/download a specific item. It's not enough to say that a certain navigation item is accessible to Managers. When the user requests Measurement 1000, we have to check that the user not only has a Manager role, but a Manager role for Measurement 1000. Summarized: How can we limit users to their accounts/measurements? (remember superusers see all measurements, some managers only specific measurements) How can we apply roles at a product/measurement level? (user X could be primarycontact for measurement 1, but just a manager for measurement 2) How can we limit manager access to the reports screen and only to their department's reports? All with the magic of asp.net classes, perhaps with a custom roleprovider implementation. Similar Stackoverflow question/problem http://stackoverflow.com/questions/1367483/asp-net-how-to-manage-users-with-different-types-of-roles

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  • On Ruby on Rails, <%= or <% should only matter whether it is show or no show, but why will it give

    - by Jian Lin
    The following code: <div id="vote_form"> <%= form_remote_tag :url => story_votes_path(@story) do %> <%= submit_tag 'shove it' %> <% end %> </div> gives compilation error while if the first <%= is replaced with <%, then everything works. I thought they only differ by "show" or "not show", but why will it actually cause a compile error? The error is: > SyntaxError in Stories#show > > Showing > app/views/stories/show.html.erb where > line #17 raised: > > compile error C:/Software > Projects/ror/shov12/app/views/stories/show.html.erb:17: > syntax error, unexpected ')' ... > story_votes_path(@story) do ).to_s); > @output_buffer.concat ... > ^ C:/Software > Projects/ror/shov12/app/views/stories/show.html.erb:23: > syntax error, unexpected kENSURE, > expecting ')' C:/Software > Projects/ror/shov12/app/views/stories/show.html.erb:25: > syntax error, unexpected kEND, > expecting ')'

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  • NSMutableArray of Objects

    - by Terry Owen
    First off I am very new to Objective C and iPhone programming. Now that that is out of the way. I have read through most of the Apple documentation on this and some third party manuals. I guess I just want to know if I'm going about this the correct way ... - (NSMutableArray *)makeModel { NSString *api = @"http://www.mycoolnewssite.com/api/v1"; NSArray *namesArray = [NSArray arrayWithObjects:@"News", @"Sports", @"Entertainment", @"Business", @"Features", nil]; NSArray *urlsArray = [NSArray arrayWithObjects: [NSString stringWithFormat:@"%@/news/news/25/stories.json", api], [NSString stringWithFormat:@"%@/news/sports/25/stories.json", api], [NSString stringWithFormat:@"%@/news/entertainment/25/stories.json", api], [NSString stringWithFormat:@"%@/news/business/25/stories.json", api], [NSString stringWithFormat:@"%@/news/features/25/stories.json", api], nil]; NSMutableArray *result = [NSMutableArray array]; for (int i = 0; i < [namesArray count]; i++) { NSMutableDictionary *objectDict = [NSMutableDictionary dictionary]; NSString *name = (NSString *)[namesArray objectAtIndex:i]; NSString *url = (NSString *)[urlsArray objectAtIndex:i]; [objectDict setObject:name forKey:@"NAME"]; [objectDict setObject:url forKey:@"URL"]; [objectDict setObject:@"NO" forKey:@"HASSTORIES"]; [result addObject:objectDict]; } return result; } Any insight would be appreciated ;-)

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  • How to use a nested form for multiple models in one form?

    - by Magicked
    I'm struggling to come up with the proper way to design a form that will allow me to input data for two different models. The form is for an 'Incident', which has the following relationships: belongs_to :customer belongs_to :user has_one :incident_status has_many :incident_notes accepts_nested_attributes_for :incident_notes, :allow_destroy => false So an incident is assigned to a 'Customer' and a 'User', and the user is able to add 'Notes' to the incident. I'm having trouble with the notes part of the form. Here how the form is being submitted: {"commit"=>"Create", "authenticity_token"=>"ECH5Ziv7JAuzs53kt5m/njT9w39UJhfJEs2x0Ms2NA0=", "customer_id"=>"4", "incident"=>{"title"=>"Something bad", "incident_status_id"=>"2", "user_id"=>"2", "other_id"=>"AAA01-042310-001", "incident_note"=>{"note"=>"This is a note"}}} It appears to be attempting to add the incident_note as a field under 'Incident', rather than creating a new entry in the incident_note table with an incident_id foreign key linking back to the incident. Here is the 'IncidentNote' model: belongs_to :incident belongs_to :user Here is the form for 'Incident': <% form_for([@customer,@incident]) do |f| %> <%= f.error_messages %> <p> <%= f.label :other_id, "ID" %><br /> <%= f.text_field :capc_id %> </p> <p> <%= f.label :title %><br /> <%= f.text_field :title %> </p> <p> <%= label_tag 'user', 'Assign to user?' %> <%= f.select :user_id, @users.collect {|u| [u.name, u.id]} %> </p> <p> <%= f.label :incident_status, 'Status?' %> <%= f.select :incident_status_id, @statuses.collect {|s| [s.name, s.id]} %> </p> <p> <% f.fields_for :incident_note do |inote_form| %> <%= inote_form.label :note, 'Add a Note' %> <%= inote_form.text_area :note, :cols => 40, :rows => 20 %> <% end %> </p> <p> <%= f.submit "Create" %> </p> <% end %> And finally, here are the incident_controller entries for New and Create. New: def new @customer = current_user.customer @incident = Incident.new @users = @customer.users @statuses = IncidentStatus.find(:all) @incident_note = IncidentNote.new respond_to do |format| format.html # new.html.erb format.xml { render :xml => @incident } end end Create: def create @users = @customer.users @statuses = IncidentStatus.find(:all) @incident = Incident.new(params[:incident]) @incident.customer = @customer @incident_note = @incident.incident_note.build(params[:incident_note]) @incident_note.user = current_user respond_to do |format| if @incident.save flash[:notice] = 'Incident was successfully created.' format.html { redirect_to(@incident) } format.xml { render :xml => @incident, :status => :created, :location => @incident } else format.html { render :action => "new" } format.xml { render :xml => @incident.errors, :status => :unprocessable_entity } end end end I'm not really sure where to look at this point. I'm sure it's just a limitation of my current Rails skill (I don't know much). So if anyone can point me in the right direction I would be very appreciative. Please let me know if more information is needed! Thanks!

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  • Increasing speed of python code

    - by Curious2learn
    Hi, I have some python code that has many classes. I used cProfile to find that the total time to run the program is 68 seconds. I found that the following function in a class called Buyers takes about 60 seconds of those 68 seconds. I have to run the program about 100 times, so any increase in speed will help. Can you suggest ways to increase the speed by modifying the code? If you need more information that will help, please let me know. def qtyDemanded(self, timePd, priceVector): '''Returns quantity demanded in period timePd. In addition, also updates the list of customers and non-customers. Inputs: timePd and priceVector Output: count of people for whom priceVector[-1] < utility ''' ## Initialize count of customers to zero ## Set self.customers and self.nonCustomers to empty lists price = priceVector[-1] count = 0 self.customers = [] self.nonCustomers = [] for person in self.people: if person.utility >= price: person.customer = 1 self.customers.append(person) else: person.customer = 0 self.nonCustomers.append(person) return len(self.customers) self.people is a list of person objects. Each person has customer and utility as its attributes. EDIT - responsed added ------------------------------------- Thanks so much for the suggestions. Here is the response to some questions and suggestions people have kindly made. I have not tried them all, but will try others and write back later. (1) @amber - the function is accessed 80,000 times. (2) @gnibbler and others - self.people is a list of Person objects in memory. Not connected to a database. (3) @Hugh Bothwell cumtime taken by the original function - 60.8 s (accessed 80000 times) cumtime taken by the new function with local function aliases as suggested - 56.4 s (accessed 80000 times) (4) @rotoglup and @Martin Thomas I have not tried your solutions yet. I need to check the rest of the code to see the places where I use self.customers before I can make the change of not appending the customers to self.customers list. But I will try this and write back. (5) @TryPyPy - thanks for your kind offer to check the code. Let me first read a little on the suggestions you have made to see if those will be feasible to use. EDIT 2 Some suggested that since I am flagging the customers and noncustomers in the self.people, I should try without creating separate lists of self.customers and self.noncustomers using append. Instead, I should loop over the self.people to find the number of customers. I tried the following code and timed both functions below f_w_append and f_wo_append. I did find that the latter takes less time, but it is still 96% of the time taken by the former. That is, it is a very small increase in the speed. @TryPyPy - The following piece of code is complete enough to check the bottleneck function, in case your offer is still there to check it with other compilers. Thanks again to everyone who replied. import numpy class person(object): def __init__(self, util): self.utility = util self.customer = 0 class population(object): def __init__(self, numpeople): self.people = [] self.cus = [] self.noncus = [] numpy.random.seed(1) utils = numpy.random.uniform(0, 300, numpeople) for u in utils: per = person(u) self.people.append(per) popn = population(300) def f_w_append(): '''Function with append''' P = 75 cus = [] noncus = [] for per in popn.people: if per.utility >= P: per.customer = 1 cus.append(per) else: per.customer = 0 noncus.append(per) return len(cus) def f_wo_append(): '''Function without append''' P = 75 for per in popn.people: if per.utility >= P: per.customer = 1 else: per.customer = 0 numcustomers = 0 for per in popn.people: if per.customer == 1: numcustomers += 1 return numcustomers

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  • Nested mysql select statements

    - by Jimmy Kamau
    I have a query as below: $sult = mysql_query("select * from stories where `categ` = 'businessnews' and `stryid`='".mysql_query("SELECT * FROM comments WHERE `comto`='".mysql_query("select * from stories where `categ` ='businessnews'")." ORDER BY COUNT(comto) DESC")."' LIMIT 3") or die(mysql_error()); while($ow=mysql_fetch_array($sult)){ The code above should return the top 3 'stories' with the most comments {count(comto)}. The comments are stored in a different table from the stories. The code above does not return any values and doesn't show any errors. Could someone please help?

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  • Efficient way to combine results of two database queries.

    - by ensnare
    I have two tables on different servers, and I'd like some help finding an efficient way to combine and match the datasets. Here's an example: From server 1, which holds our stories, I perform a query like: query = """SELECT author_id, title, text FROM stories ORDER BY timestamp_created DESC LIMIT 10 """ results = DB.getAll(query) for i in range(len(results)): #Build a string of author_ids, e.g. '1314,4134,2624,2342' But, I'd like to fetch some info about each author_id from server 2: query = """SELECT id, avatar_url FROM members WHERE id IN (%s) """ values = (uid_list) results = DB.getAll(query, values) Now I need some way to combine these two queries so I have a dict that has the story as well as avatar_url and member_id. If this data were on one server, it would be a simple join that would look like: SELECT * FROM members, stories WHERE members.id = stories.author_id But since we store the data on multiple servers, this is not possible. What is the most efficient way to do this? Thanks.

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  • Using RIA DomainServices with ASP.NET and MVC 2

    - by Bobby Diaz
    Recently, I started working on a new ASP.NET MVC 2 project and I wanted to reuse the data access (LINQ to SQL) and business logic methods (WCF RIA Services) that had been developed for a previous project that used Silverlight for the front-end.  I figured that I would be able to instantiate the various DomainService classes from within my controller’s action methods, because after all, the code for those services didn’t look very complicated.  WRONG!  I didn’t realize at first that some of the functionality is handled automatically by the framework when the domain services are hosted as WCF services.  After some initial searching, I came across an invaluable post by Joe McBride, which described how to get RIA Service .svc files to work in an MVC 2 Web Application, and another by Brad Abrams.  Unfortunately, Brad’s solution was for an earlier preview release of RIA Services and no longer works with the version that I am running (PDC Preview). I have not tried the RC version of WCF RIA Services, so I am not sure if any of the issues I am having have been resolved, but I wanted to come up with a way to reuse the shared libraries so I wouldn’t have to write a non-RIA version that basically did the same thing.  The classes I came up with work with the scenarios I have encountered so far, but I wanted to go ahead and post the code in case someone else is having the same trouble I had.  Hopefully this will save you a few headaches! 1. Querying When I first tried to use a DomainService class to perform a query inside one of my controller’s action methods, I got an error stating that “This DomainService has not been initialized.”  To solve this issue, I created an extension method for all DomainServices that creates the required DomainServiceContext and passes it to the service’s Initialize() method.  Here is the code for the extension method; notice that I am creating a sort of mock HttpContext for those cases when the service is running outside of IIS, such as during unit testing!     public static class ServiceExtensions     {         /// <summary>         /// Initializes the domain service by creating a new <see cref="DomainServiceContext"/>         /// and calling the base DomainService.Initialize(DomainServiceContext) method.         /// </summary>         /// <typeparam name="TService">The type of the service.</typeparam>         /// <param name="service">The service.</param>         /// <returns></returns>         public static TService Initialize<TService>(this TService service)             where TService : DomainService         {             var context = CreateDomainServiceContext();             service.Initialize(context);             return service;         }           private static DomainServiceContext CreateDomainServiceContext()         {             var provider = new ServiceProvider(new HttpContextWrapper(GetHttpContext()));             return new DomainServiceContext(provider, DomainOperationType.Query);         }           private static HttpContext GetHttpContext()         {             var context = HttpContext.Current;   #if DEBUG             // create a mock HttpContext to use during unit testing...             if ( context == null )             {                 var writer = new StringWriter();                 var request = new SimpleWorkerRequest("/", "/",                     String.Empty, String.Empty, writer);                   context = new HttpContext(request)                 {                     User = new GenericPrincipal(new GenericIdentity("debug"), null)                 };             } #endif               return context;         }     }   With that in place, I can use it almost as normally as my first attempt, except with a call to Initialize():     public ActionResult Index()     {         var service = new NorthwindService().Initialize();         var customers = service.GetCustomers();           return View(customers);     } 2. Insert / Update / Delete Once I got the records showing up, I was trying to insert new records or update existing data when I ran into the next issue.  I say issue because I wasn’t getting any kind of error, which made it a little difficult to track down.  But once I realized that that the DataContext.SubmitChanges() method gets called automatically at the end of each domain service submit operation, I could start working on a way to mimic the behavior of a hosted domain service.  What I came up with, was a base class called LinqToSqlRepository<T> that basically sits between your implementation and the default LinqToSqlDomainService<T> class.     [EnableClientAccess()]     public class NorthwindService : LinqToSqlRepository<NorthwindDataContext>     {         public IQueryable<Customer> GetCustomers()         {             return this.DataContext.Customers;         }           public void InsertCustomer(Customer customer)         {             this.DataContext.Customers.InsertOnSubmit(customer);         }           public void UpdateCustomer(Customer currentCustomer)         {             this.DataContext.Customers.TryAttach(currentCustomer,                 this.ChangeSet.GetOriginal(currentCustomer));         }           public void DeleteCustomer(Customer customer)         {             this.DataContext.Customers.TryAttach(customer);             this.DataContext.Customers.DeleteOnSubmit(customer);         }     } Notice the new base class name (just change LinqToSqlDomainService to LinqToSqlRepository).  I also added a couple of DataContext (for Table<T>) extension methods called TryAttach that will check to see if the supplied entity is already attached before attempting to attach it, which would cause an error! 3. LinqToSqlRepository<T> Below is the code for the LinqToSqlRepository class.  The comments are pretty self explanatory, but be aware of the [IgnoreOperation] attributes on the generic repository methods, which ensures that they will be ignored by the code generator and not available in the Silverlight client application.     /// <summary>     /// Provides generic repository methods on top of the standard     /// <see cref="LinqToSqlDomainService&lt;TContext&gt;"/> functionality.     /// </summary>     /// <typeparam name="TContext">The type of the context.</typeparam>     public abstract class LinqToSqlRepository<TContext> : LinqToSqlDomainService<TContext>         where TContext : System.Data.Linq.DataContext, new()     {         /// <summary>         /// Retrieves an instance of an entity using it's unique identifier.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="keyValues">The key values.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual TEntity GetById<TEntity>(params object[] keyValues) where TEntity : class         {             var table = this.DataContext.GetTable<TEntity>();             var mapping = this.DataContext.Mapping.GetTable(typeof(TEntity));               var keys = mapping.RowType.IdentityMembers                 .Select((m, i) => m.Name + " = @" + i)                 .ToArray();               return table.Where(String.Join(" && ", keys), keyValues).FirstOrDefault();         }           /// <summary>         /// Creates a new query that can be executed to retrieve a collection         /// of entities from the <see cref="DataContext"/>.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <returns></returns>         [IgnoreOperation]         public virtual IQueryable<TEntity> GetEntityQuery<TEntity>() where TEntity : class         {             return this.DataContext.GetTable<TEntity>();         }           /// <summary>         /// Inserts the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Insert<TEntity>(TEntity entity) where TEntity : class         {             //var table = this.DataContext.GetTable<TEntity>();             //table.InsertOnSubmit(entity);               return this.Submit(entity, null, DomainOperation.Insert);         }           /// <summary>         /// Updates the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Update<TEntity>(TEntity entity) where TEntity : class         {             return this.Update(entity, null);         }           /// <summary>         /// Updates the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <param name="original">The original.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Update<TEntity>(TEntity entity, TEntity original)             where TEntity : class         {             if ( original == null )             {                 original = GetOriginal(entity);             }               var table = this.DataContext.GetTable<TEntity>();             table.TryAttach(entity, original);               return this.Submit(entity, original, DomainOperation.Update);         }           /// <summary>         /// Deletes the specified entity.         /// </summary>         /// <typeparam name="TEntity">The type of the entity.</typeparam>         /// <param name="entity">The entity.</param>         /// <returns></returns>         [IgnoreOperation]         public virtual bool Delete<TEntity>(TEntity entity) where TEntity : class         {             //var table = this.DataContext.GetTable<TEntity>();             //table.TryAttach(entity);             //table.DeleteOnSubmit(entity);               return this.Submit(entity, null, DomainOperation.Delete);         }           protected virtual bool Submit(Object entity, Object original, DomainOperation operation)         {             var entry = new ChangeSetEntry(0, entity, original, operation);             var changes = new ChangeSet(new ChangeSetEntry[] { entry });             return base.Submit(changes);         }           private TEntity GetOriginal<TEntity>(TEntity entity) where TEntity : class         {             var context = CreateDataContext();             var table = context.GetTable<TEntity>();             return table.FirstOrDefault(e => e == entity);         }     } 4. Conclusion So there you have it, a fully functional Repository implementation for your RIA Domain Services that can be consumed by your ASP.NET and MVC applications.  I have uploaded the source code along with unit tests and a sample web application that queries the Customers table from inside a Controller, as well as a Silverlight usage example. As always, I welcome any comments or suggestions on the approach I have taken.  If there is enough interest, I plan on contacting Colin Blair or maybe even the man himself, Brad Abrams, to see if this is something worthy of inclusion in the WCF RIA Services Contrib project.  What do you think? Enjoy!

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  • Solving Big Problems with Oracle R Enterprise, Part II

    - by dbayard
    Part II – Solving Big Problems with Oracle R Enterprise In the first post in this series (see https://blogs.oracle.com/R/entry/solving_big_problems_with_oracle), we showed how you can use R to perform historical rate of return calculations against investment data sourced from a spreadsheet.  We demonstrated the calculations against sample data for a small set of accounts.  While this worked fine, in the real-world the problem is much bigger because the amount of data is much bigger.  So much bigger that our approach in the previous post won’t scale to meet the real-world needs. From our previous post, here are the challenges we need to conquer: The actual data that needs to be used lives in a database, not in a spreadsheet The actual data is much, much bigger- too big to fit into the normal R memory space and too big to want to move across the network The overall process needs to run fast- much faster than a single processor The actual data needs to be kept secured- another reason to not want to move it from the database and across the network And the process of calculating the IRR needs to be integrated together with other database ETL activities, so that IRR’s can be calculated as part of the data warehouse refresh processes In this post, we will show how we moved from sample data environment to working with full-scale data.  This post is based on actual work we did for a financial services customer during a recent proof-of-concept. Getting started with the Database At this point, we have some sample data and our IRR function.  We were at a similar point in our customer proof-of-concept exercise- we had sample data but we did not have the full customer data yet.  So our database was empty.  But, this was easily rectified by leveraging the transparency features of Oracle R Enterprise (see https://blogs.oracle.com/R/entry/analyzing_big_data_using_the).  The following code shows how we took our sample data SimpleMWRRData and easily turned it into a new Oracle database table called IRR_DATA via ore.create().  The code also shows how we can access the database table IRR_DATA as if it was a normal R data.frame named IRR_DATA. If we go to sql*plus, we can also check out our new IRR_DATA table: At this point, we now have our sample data loaded in the database as a normal Oracle table called IRR_DATA.  So, we now proceeded to test our R function working with database data. As our first test, we retrieved the data from a single account from the IRR_DATA table, pull it into local R memory, then call our IRR function.  This worked.  No SQL coding required! Going from Crawling to Walking Now that we have shown using our R code with database-resident data for a single account, we wanted to experiment with doing this for multiple accounts.  In other words, we wanted to implement the split-apply-combine technique we discussed in our first post in this series.  Fortunately, Oracle R Enterprise provides a very scalable way to do this with a function called ore.groupApply().  You can read more about ore.groupApply() here: https://blogs.oracle.com/R/entry/analyzing_big_data_using_the1 Here is an example of how we ask ORE to take our IRR_DATA table in the database, split it by the ACCOUNT column, apply a function that calls our SimpleMWRR() calculation, and then combine the results. (If you are following along at home, be sure to have installed our myIRR package on your database server via  “R CMD INSTALL myIRR”). The interesting thing about ore.groupApply is that the calculation is not actually performed in my desktop R environment from which I am running.  What actually happens is that ore.groupApply uses the Oracle database to perform the work.  And the Oracle database is what actually splits the IRR_DATA table by ACCOUNT.  Then the Oracle database takes the data for each account and sends it to an embedded R engine running on the database server to apply our R function.  Then the Oracle database combines all the individual results from the calls to the R function. This is significant because now the embedded R engine only needs to deal with the data for a single account at a time.  Regardless of whether we have 20 accounts or 1 million accounts or more, the R engine that performs the calculation does not care.  Given that normal R has a finite amount of memory to hold data, the ore.groupApply approach overcomes the R memory scalability problem since we only need to fit the data from a single account in R memory (not all of the data for all of the accounts). Additionally, the IRR_DATA does not need to be sent from the database to my desktop R program.  Even though I am invoking ore.groupApply from my desktop R program, because the actual SimpleMWRR calculation is run by the embedded R engine on the database server, the IRR_DATA does not need to leave the database server- this is both a performance benefit because network transmission of large amounts of data take time and a security benefit because it is harder to protect private data once you start shipping around your intranet. Another benefit, which we will discuss in a few paragraphs, is the ability to leverage Oracle database parallelism to run these calculations for dozens of accounts at once. From Walking to Running ore.groupApply is rather nice, but it still has the drawback that I run this from a desktop R instance.  This is not ideal for integrating into typical operational processes like nightly data warehouse refreshes or monthly statement generation.  But, this is not an issue for ORE.  Oracle R Enterprise lets us run this from the database using regular SQL, which is easily integrated into standard operations.  That is extremely exciting and the way we actually did these calculations in the customer proof. As part of Oracle R Enterprise, it provides a SQL equivalent to ore.groupApply which it refers to as “rqGroupEval”.  To use rqGroupEval via SQL, there is a bit of simple setup needed.  Basically, the Oracle Database needs to know the structure of the input table and the grouping column, which we are able to define using the database’s pipeline table function mechanisms. Here is the setup script: At this point, our initial setup of rqGroupEval is done for the IRR_DATA table.  The next step is to define our R function to the database.  We do that via a call to ORE’s rqScriptCreate. Now we can test it.  The SQL you use to run rqGroupEval uses the Oracle database pipeline table function syntax.  The first argument to irr_dataGroupEval is a cursor defining our input.  You can add additional where clauses and subqueries to this cursor as appropriate.  The second argument is any additional inputs to the R function.  The third argument is the text of a dummy select statement.  The dummy select statement is used by the database to identify the columns and datatypes to expect the R function to return.  The fourth argument is the column of the input table to split/group by.  The final argument is the name of the R function as you defined it when you called rqScriptCreate(). The Real-World Results In our real customer proof-of-concept, we had more sophisticated calculation requirements than shown in this simplified blog example.  For instance, we had to perform the rate of return calculations for 5 separate time periods, so the R code was enhanced to do so.  In addition, some accounts needed a time-weighted rate of return to be calculated, so we extended our approach and added an R function to do that.  And finally, there were also a few more real-world data irregularities that we needed to account for, so we added logic to our R functions to deal with those exceptions.  For the full-scale customer test, we loaded the customer data onto a Half-Rack Exadata X2-2 Database Machine.  As our half-rack had 48 physical cores (and 96 threads if you consider hyperthreading), we wanted to take advantage of that CPU horsepower to speed up our calculations.  To do so with ORE, it is as simple as leveraging the Oracle Database Parallel Query features.  Let’s look at the SQL used in the customer proof: Notice that we use a parallel hint on the cursor that is the input to our rqGroupEval function.  That is all we need to do to enable Oracle to use parallel R engines. Here are a few screenshots of what this SQL looked like in the Real-Time SQL Monitor when we ran this during the proof of concept (hint: you might need to right-click on these images to be able to view the images full-screen to see the entire image): From the above, you can notice a few things (numbers 1 thru 5 below correspond with highlighted numbers on the images above.  You may need to right click on the above images and view the images full-screen to see the entire image): The SQL completed in 110 seconds (1.8minutes) We calculated rate of returns for 5 time periods for each of 911k accounts (the number of actual rows returned by the IRRSTAGEGROUPEVAL operation) We accessed 103m rows of detailed cash flow/market value data (the number of actual rows returned by the IRR_STAGE2 operation) We ran with 72 degrees of parallelism spread across 4 database servers Most of our 110seconds was spent in the “External Procedure call” event On average, we performed 8,200 executions of our R function per second (110s/911k accounts) On average, each execution was passed 110 rows of data (103m detail rows/911k accounts) On average, we did 41,000 single time period rate of return calculations per second (each of the 8,200 executions of our R function did rate of return calculations for 5 time periods) On average, we processed over 900,000 rows of database data in R per second (103m detail rows/110s) R + Oracle R Enterprise: Best of R + Best of Oracle Database This blog post series started by describing a real customer problem: how to perform a lot of calculations on a lot of data in a short period of time.  While standard R proved to be a very good fit for writing the necessary calculations, the challenge of working with a lot of data in a short period of time remained. This blog post series showed how Oracle R Enterprise enables R to be used in conjunction with the Oracle Database to overcome the data volume and performance issues (as well as simplifying the operations and security issues).  It also showed that we could calculate 5 time periods of rate of returns for almost a million individual accounts in less than 2 minutes. In a future post, we will take the same R function and show how Oracle R Connector for Hadoop can be used in the Hadoop world.  In that next post, instead of having our data in an Oracle database, our data will live in Hadoop and we will how to use the Oracle R Connector for Hadoop and other Oracle Big Data Connectors to move data between Hadoop, R, and the Oracle Database easily.

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  • SSIS - XML Source Script

    - by simonsabin
    The XML Source in SSIS is great if you have a 1 to 1 mapping between entity and table. You can do more complex mapping but it becomes very messy and won't perform. What other options do you have? The challenge with XML processing is to not need a huge amount of memory. I remember using the early versions of Biztalk with loaded the whole document into memory to map from one document type to another. This was fine for small documents but was an absolute killer for large documents. You therefore need a streaming approach. For flexibility however you want to be able to generate your rows easily, and if you've ever used the XmlReader you will know its ugly code to write. That brings me on to LINQ. The is an implementation of LINQ over XML which is really nice. You can write nice LINQ queries instead of the XMLReader stuff. The downside is that by default LINQ to XML requires a whole XML document to work with. No streaming. Your code would look like this. We create an XDocument and then enumerate over a set of annoymous types we generate from our LINQ statement XDocument x = XDocument.Load("C:\\TEMP\\CustomerOrders-Attribute.xml");   foreach (var xdata in (from customer in x.Elements("OrderInterface").Elements("Customer")                        from order in customer.Elements("Orders").Elements("Order")                        select new { Account = customer.Attribute("AccountNumber").Value                                   , OrderDate = order.Attribute("OrderDate").Value }                        )) {     Output0Buffer.AddRow();     Output0Buffer.AccountNumber = xdata.Account;     Output0Buffer.OrderDate = Convert.ToDateTime(xdata.OrderDate); } As I said the downside to this is that you are loading the whole document into memory. I did some googling and came across some helpful videos from a nice UK DPE Mike Taulty http://www.microsoft.com/uk/msdn/screencasts/screencast/289/LINQ-to-XML-Streaming-In-Large-Documents.aspx. Which show you how you can combine LINQ and the XmlReader to get a semi streaming approach. I took what he did and implemented it in SSIS. What I found odd was that when I ran it I got different numbers between using the streamed and non streamed versions. I found the cause was a little bug in Mikes code that causes the pointer in the XmlReader to progress past the start of the element and thus foreach (var xdata in (from customer in StreamReader("C:\\TEMP\\CustomerOrders-Attribute.xml","Customer")                                from order in customer.Elements("Orders").Elements("Order")                                select new { Account = customer.Attribute("AccountNumber").Value                                           , OrderDate = order.Attribute("OrderDate").Value }                                ))         {             Output0Buffer.AddRow();             Output0Buffer.AccountNumber = xdata.Account;             Output0Buffer.OrderDate = Convert.ToDateTime(xdata.OrderDate);         } These look very similiar and they are the key element is the method we are calling, StreamReader. This method is what gives us streaming, what it does is return a enumerable list of elements, because of the way that LINQ works this results in the data being streamed in. static IEnumerable<XElement> StreamReader(String filename, string elementName) {     using (XmlReader xr = XmlReader.Create(filename))     {         xr.MoveToContent();         while (xr.Read()) //Reads the first element         {             while (xr.NodeType == XmlNodeType.Element && xr.Name == elementName)             {                 XElement node = (XElement)XElement.ReadFrom(xr);                   yield return node;             }         }         xr.Close();     } } This code is specifically designed to return a list of the elements with a specific name. The first Read reads the root element and then the inner while loop checks to see if the current element is the type we want. If not we do the xr.Read() again until we find the element type we want. We then use the neat function XElement.ReadFrom to read an element and all its sub elements into an XElement. This is what is returned and can be consumed by the LINQ statement. Essentially once one element has been read we need to check if we are still on the same element type and name (the inner loop) This was Mikes mistake, if we called .Read again we would advance the XmlReader beyond the start of the Element and so the ReadFrom method wouldn't work. So with the code above you can use what ever LINQ statement you like to flatten your XML into the rowsets you want. You could even have multiple outputs and generate your own surrogate keys.        

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