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  • CQRS - The query side

    - by mattcodes
    A lot of the blogsphere articles related to CQRS (command query repsonsibility) seperation seem to imply that all screens/viewmodels are flat. e.g. Name, Age, Location Of Birth etc.. and thus the suggestion that implementation wise we stick them into fast read source etc.. single table per view mySQL etc.. and pull them out with something like primitive SqlDataReader, kick that nasty nhibernate ORM etc.. However, whilst I agree that domain models dont mapped well to most screens, many of the screens that I work with are more dimensional, and Im sure this is pretty common in LOB apps. So my question is how are people handling screen where by for example it displays a summary of customer details and then a list of their orders with a [more detail] link etc.... I thought about keeping with the straight forward SQL query to the Query Database breaking off the outer join so can build a suitable ViewModel to View but it seems like overkill? Alternatively (this is starting to feel yuck) in CustomerSummaryView table have a text/big (whatever the type is in your DB) column called Orders, and the columns for the Order summary screen grid are seperated by , and rows by |. Even with XML datatype it still feeel dirty. Any thoughts on an optimal practice?

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  • Making a DateTime field in a database automatic?

    - by Mike
    I'm putting together a simple test database to learn MVC with. I want to add a DateTime field to show when the record was CREATED. ID = int Name = Char DateCreated = (dateTime, DateTime2..?) I have a feeling that this type of DateTime capture can be done automatically - but that's all I have, a feeling. Can it be done? And if so how? While we're on the subject: if I wanted to include another field that captured the DateTime of when the record was LAST UPDATED how would I do that. I'm hoping to not do this manually. Many thanks Mike

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  • Extend base type and automatically update audit information on Entity

    - by Nix
    I have an entity model that has audit information on every table (50+ tables) CreateDate CreateUser UpdateDate UpdateUser Currently we are programatically updating audit information. Ex: if(changed){ entity.UpdatedOn = DateTime.Now; entity.UpdatedBy = Environment.UserName; context.SaveChanges(); } But I am looking for a more automated solution. During save changes, if an entity is created/updated I would like to automatically update these fields before sending them to the database for storage. Any suggestion on how i could do this? I would prefer to not do any reflection, so using a text template is not out of the question. A solution has been proposed to override SaveChanges and do it there, but in order to achieve this i would either have to use reflection (in which I don't want to do ) or derive a base class. Assuming i go down this route how would I achieve this? For example EXAMPLE_DB_TABLE CODE NAME --Audit Tables CREATE_DATE CREATE_USER UPDATE_DATE UPDATE_USER And if i create a base class public abstract class IUpdatable{ public virtual DateTime CreateDate {set;} public virtual string CreateUser { set;} public virtual DateTime UpdateDate { set;} public virtual string UpdateUser { set;} } The end goal is to be able to do something like... public overrride void SaveChanges(){ //Go through state manager and update audit infromation //FOREACH changed entity in state manager if(entity is IUpdatable){ //If state is created... update create audit. //if state is updated... update update audit } } But I am not sure how I go about generating the code that would extend the interface.

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  • Web App for smartphones in ASPX

    - by Ryan Knoll
    I have been looking around recently to try and find a good place to learn how to start making my website more smartphone friendly when it is visited by an iPhone, android, or blackberry. This is something like what Digg.com does when it is visited by a smartphone. I have found a few tutorials for PHP but none for ASPX, and all I have is windows servers. Could anyone point me in the right direction, and show me were to find a quick run through on how to do something like this? I am a bit lost. :(

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  • How you would you describe the Observer pattern in beginner language?

    - by Sheldon
    Currently, my level of understanding is below all the coding examples on the web about the Observer Pattern. I understand it simply as being almost a subscription that updates all other events when a change is made that the delegate registers. However, I'm very unstable in my true comprehension of the benefits and uses. I've done some googling, but most are above my level of understanding. I'm trying to implement this pattern with my current homework assignment, and to truly make sense on my project need a better understanding of the pattern itself and perhaps an example to see what its use. I don't want to force this pattern into something just to submit, I need to understand the purpose and develop my methods accordingly so that it actually serves a good purpose. My text doesn't really go into it, just mentions it in one sentence. MSDN was hard for me to understand, as I'm a beginner on this, and it seems more of an advanced topic. How would you describe this Observer pattern and its uses in C# to a beginner? For an example, please keep code very simple so I can understand the purpose more than complex code snippets. I'm trying to use it effectively with some simple textbox string manipulations and using delegates for my assignment, so a pointer would help!

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  • Python - help on custom wx.Python (pyDev) class

    - by Wallter
    I have been hitting a dead end with this program. I am trying to build a class that will let me control the BIP's of a button when it is in use. so far this is what i have (see following.) It keeps running this weird error TypeError: 'module' object is not callable - I, coming from C++ and C# (for some reason the #include... is so much easier) , have no idea what that means, Google is of no help so... I know I need some real help with sintax and such - anything woudl be helpful. Note: The base code found here was used to create a skeleton for this 'custom button class' Custom Button import wx from wxPython.wx import * class Custom_Button(wx.PyControl): # The BMP's # AM I DOING THIS RIGHT? - I am trying to get empty 'global' # variables within the class Mouse_over_bmp = None #wxEmptyBitmap(1,1,1) # When the mouse is over Norm_bmp = None #wxEmptyBitmap(1,1,1) # The normal BMP Push_bmp = None #wxEmptyBitmap(1,1,1) # The down BMP Pos_bmp = wx.Point(0,0) # The posisition of the button def __init__(self, parent, NORM_BMP, PUSH_BMP, MOUSE_OVER_BMP, pos, size, text="", id=-1, **kwargs): wx.PyControl.__init__(self,parent, id, **kwargs) # The conversions, hereafter, were to solve another but. I don't know if it is # necessary to do this since the source being given to the class (in this case) # is a BMP - is there a better way to prevent an error that i have not # stumbled accost? # Set the BMP's to the ones given in the constructor self.Mouse_over_bmp = wx.Bitmap(wx.Image(MOUSE_OVER_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) self.Norm_bmp = wx.Bitmap(wx.Image(NORM_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) self.Push_bmp = wx.Bitmap(wx.Image(PUSH_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) self.Pos_bmp = self.pos self.Bind(wx.EVT_LEFT_DOWN, self._onMouseDown) self.Bind(wx.EVT_LEFT_UP, self._onMouseUp) self.Bind(wx.EVT_LEAVE_WINDOW, self._onMouseLeave) self.Bind(wx.EVT_ENTER_WINDOW, self._onMouseEnter) self.Bind(wx.EVT_ERASE_BACKGROUND,self._onEraseBackground) self.Bind(wx.EVT_PAINT,self._onPaint) self._mouseIn = self._mouseDown = False def _onMouseEnter(self, event): self._mouseIn = True def _onMouseLeave(self, event): self._mouseIn = False def _onMouseDown(self, event): self._mouseDown = True def _onMouseUp(self, event): self._mouseDown = False self.sendButtonEvent() def sendButtonEvent(self): event = wx.CommandEvent(wx.wxEVT_COMMAND_BUTTON_CLICKED, self.GetId()) event.SetInt(0) event.SetEventObject(self) self.GetEventHandler().ProcessEvent(event) def _onEraseBackground(self,event): # reduce flicker pass def _onPaint(self, event): dc = wx.BufferedPaintDC(self) dc.SetFont(self.GetFont()) dc.SetBackground(wx.Brush(self.GetBackgroundColour())) dc.Clear() dc.DrawBitmap(self.Norm_bmp) # draw whatever you want to draw # draw glossy bitmaps e.g. dc.DrawBitmap if self._mouseIn: # If the Mouse is over the button dc.DrawBitmap(self, self.Mouse_over_bmp, self.Pos_bmp, useMask=False) if self._mouseDown: # If the Mouse clicks the button dc.DrawBitmap(self, self.Push_bmp, self.Pos_bmp, useMask=False) Main.py import wx import Custom_Button from wxPython.wx import * ID_ABOUT = 101 ID_EXIT = 102 class MyFrame(wx.Frame): def __init__(self, parent, ID, title): wxFrame.__init__(self, parent, ID, title, wxDefaultPosition, wxSize(400, 400)) self.CreateStatusBar() self.SetStatusText("Program testing custom button overlays") menu = wxMenu() menu.Append(ID_ABOUT, "&About", "More information about this program") menu.AppendSeparator() menu.Append(ID_EXIT, "E&xit", "Terminate the program") menuBar = wxMenuBar() menuBar.Append(menu, "&File"); self.SetMenuBar(menuBar) self.Button1 = Custom_Button(self, parent, -1, "D:/Documents/Python/Normal.bmp", "D:/Documents/Python/Clicked.bmp", "D:/Documents/Python/Over.bmp", wx.Point(200,200), wx.Size(300,100)) EVT_MENU(self, ID_ABOUT, self.OnAbout) EVT_MENU(self, ID_EXIT, self.TimeToQuit) def OnAbout(self, event): dlg = wxMessageDialog(self, "Testing the functions of custom " "buttons using pyDev and wxPython", "About", wxOK | wxICON_INFORMATION) dlg.ShowModal() dlg.Destroy() def TimeToQuit(self, event): self.Close(true) class MyApp(wx.App): def OnInit(self): frame = MyFrame(NULL, -1, "wxPython | Buttons") frame.Show(true) self.SetTopWindow(frame) return true app = MyApp(0) app.MainLoop() Errors (and traceback) /home/wallter/python/Custom Button overlay/src/Custom_Button.py:8: DeprecationWarning: The wxPython compatibility package is no longer automatically generated or actively maintained. Please switch to the wx package as soon as possible. I have never been able to get this to go away whenever using wxPython any help? from wxPython.wx import * Traceback (most recent call last): File "/home/wallter/python/Custom Button overlay/src/Main.py", line 57, in <module> app = MyApp(0) File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7978, in __init__ self._BootstrapApp() File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7552, in _BootstrapApp return _core_.PyApp__BootstrapApp(*args, **kwargs) File "/home/wallter/python/Custom Button overlay/src/Main.py", line 52, in OnInit frame = MyFrame(NULL, -1, "wxPython | Buttons") File "/home/wallter/python/Custom Button overlay/src/Main.py", line 32, in __init__ wx.Point(200,200), wx.Size(300,100)) TypeError: 'module' object is not callable I have tried removing the "wx.Point(200,200), wx.Size(300,100))" just to have the error move up to the line above. Have I declared it right? help?

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  • Most Astonishing Violation of the Principle of Least Astonishment

    - by Adam Liss
    The Principle of Least Astonishment suggests that a system should operate as a user would expect it to, as much as possible. In other words, it should never "astonish" the user with unexpected behavior. In your experience as the "astonishee," what types of systems are the worst offenders, and if you were the project manager, how would you correct the problem? Bonus if your answer describes how you'd retrain the developers!

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  • Converting old WCF service to RIA one

    - by Artur
    Hi there, Currently I have a service that looks like: Some app <-- WCF Service <-- Business Logic <-- Entity Framework Model <-- SQL Database One of "some app" would be Silverlight, but there as well will be lots of other clients (mainly mobile devices). To me the greatest benefit of having RIA services is possibility of making ordinary (not asynchronous) calls from Silverlight. I wondered if there is an easy way of converting what I have so far to be a RIA service? I as well wonder if there is a point of doing so if I plan to use the same service for multiple platforms/clients? Any help/links would be greatly appreciated.

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  • Allocation algorithm help, using Python.

    - by Az
    Hi there, I've been working on this general allocation algorithm for students. The pseudocode for it (a Python implementation) is: for a student in a dictionary of students: for student's preference in a set of preferences (ordered from 1 to 10): let temp_project be the first preferred project check if temp_project is available if so, allocate it to them and make the project UNavailable to others Quite simply this will try to allocate projects by starting from their most preferred. The way it works, out of a set of say 100 projects, you list 10 you would want to do. So the 10th project wouldn't be the "least preferred overall" but rather the least preferred in their chosen set, which isn't so bad. Obviously if it can't allocate a project, a student just reverts to the base case which is an allocation of None, with a rank of 11. What I'm doing is calculating the allocation "quality" based on a weighted sum of the ranks. So the lower the numbers (i.e. more highly preferred projects), the better the allocation quality (i.e. more students have highly preferred projects). That's basically what I've currently got. Simple and it works. Now I'm working on this algorithm that tries to minimise the allocation weight locally (this pseudocode is a bit messy, sorry). The only reason this will probably work is because my "search space" as it is, isn't particularly large (just a very general, anecdotal observation, mind you). Since the project is only specific to my Department, we have their own limits imposed. So the number of students can't exceed 100 and the number of preferences won't exceed 10. for student in a dictionary/list/whatever of students: where i = 0 take the (i)st student, (i+1)nd student for their ranks: allocate the projects and set local_weighting to be sum(student_i.alloc_proj_rank, student_i+1.alloc_proj_rank) these are the cases: if local_weighting is 2 (i.e. both ranks are 1): then i += 1 and and continue above if local weighting is = N>2 (i.e. one or more ranks are greater than 1): let temp_local_weighting be N: pick student with lowest rank and then move him to his next rank and pick the other student and reallocate his project after this if temp_local_weighting is < N: then allocate those projects to the students move student with lowest rank to the next rank and reallocate other if temp_local_weighting < previous_temp_allocation: let these be the new allocated projects try moving for the lowest rank and reallocate other else: if this weighting => previous_weighting let these be the allocated projects i += 1 and move on for the rest of the students So, questions: This is sort of a modification of simulated annealing, but any sort of comments on this would be appreciated. How would I keep track of which student is (i) and which student is (i+1) If my overall list of students is 100, then the thing would mess up on (i+1) = 101 since there is none. How can I circumvent that? Any immediate flaws that can be spotted? Extra info: My students dictionary is designed as such: students[student_id] = Student(student_id, student_name, alloc_proj, alloc_proj_rank, preferences) where preferences is in the form of a dictionary such that preferences[rank] = {project_id}

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  • inner class within Interface

    - by harigm
    is that possible to create a inner class within an interface? If yes, why do we create like that? Anyways we are not going to create any interface objects? Do they help in any Development process?

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  • Best code structure for arcade games

    - by user280454
    Hi, I've developed a few arcade games so far and have the following structure in almost all of them: I have 1 file which contains a class called kernel with the following functions: init() welcome_screen() menu_screen() help_Screen() play_game() end_screen() And another file, called Game, which basically calls all these functions and controls the flow of the game. Also, I have classes for different characters, whenever required. Is this a good code structure, or should I try having different files(classes) for different functions like welcome screen, playing, help screen, etc? As in, instead of including all the code for these things in 1 file, should I be having different classes for each one of them? The only problem I think it might cause is that I would need certain variables like score, characters, etc which are common to all of them, that's why I have all these functions in a Kernel class so that all these functions can use these variables.

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  • Semantic Grid System, Media Query issue

    - by Andy
    I'm using the Semantic Grid System to build a responsive site. However, something isn't quite right with the media queries that should obviously kick in once it hits a particular screen size. I'll reference what i mean with their example on the website : if I view this on my iPhone for example, given that it is supposed to adjust to a single column structure on a mobile device, it still throws out the web version of the page. That is true for both Safari and Chrome on my iPhone. However, if I use the RWD bookmarklet to check it's appearance at different resolutions it appears as expected for the mobile resolution. Also, ironically, if I resize the page in Safari on my desktop it also adjusts accordingly once I get down to the approriate screen size, but not in Firefox. The media query that it uses once it hits 720px is @media screen and (max-width: 720px) { #maincolumn, #sidebar { .column(12); margin-bottom: 1em; } } and I might be wide of the mark here but I think that must be the issue. But given that this is directly from the semantic.gs website I'm not inclined to question their own code. Any idea what the problem might be?

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  • "Public" nested classes or not

    - by Frederick
    Suppose I have a class 'Application'. In order to be initialised it takes certain settings in the constructor. Let's also assume that the number of settings is so many that it's compelling to place them in a class of their own. Compare the following two implementations of this scenario. Implementation 1: class Application { Application(ApplicationSettings settings) { //Do initialisation here } } class ApplicationSettings { //Settings related methods and properties here } Implementation 2: class Application { Application(Application.Settings settings) { //Do initialisation here } class Settings { //Settings related methods and properties here } } To me, the second approach is very much preferable. It is more readable because it strongly emphasises the relation between the two classes. When I write code to instantiate Application class anywhere, the second approach is going to look prettier. Now just imagine the Settings class itself in turn had some similarly "related" class and that class in turn did so too. Go only three such levels and the class naming gets out out of hand in the 'non-nested' case. If you nest, however, things still stay elegant. Despite the above, I've read people saying on StackOverflow that nested classes are justified only if they're not visible to the outside world; that is if they are used only for the internal implementation of the containing class. The commonly cited objection is bloating the size of containing class's source file, but partial classes is the perfect solution for that problem. My question is, why are we wary of the "publicly exposed" use of nested classes? Are there any other arguments against such use?

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  • What makes a bad programming language bad?

    - by sub
    We have all seen things like the typing system of JavaScript (There is a funny post including a truth table somewhere around here). I consider this one of the main things that makes a programming language bad. Other things that spring to mind: Bad Error messages (Either obfuscated so you can't figure out whats wrong, not existing or simply too long and red) The language wasn't planned and just grew uncontrolled in all directions (PHP?) The language encourages bad programm(er/ing) habits such as: Global variables everywhere, bad variable names Inconsistent naming conventions inside the language I can't come up with any more at the moment and would be very happy to read what you think about this. What shouldn't be missing in a language created to be as bad (from the perspectives of the programmer, the company that hires to programmer, the team leader and the customer) as possible? (I ask this because I'm designing a bad, experimental language at the moment)

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  • Clear all class variables between instances

    - by ensnare
    This is probably a stupid question, but what's the best way to clear class variables between instances? I know I could reset each variable individually in the constructor; but is there a way to do this in bulk? Or am I doing something totally wrong that requires a different approach? Thanks for helping ... class User(): def __init__(self): #RESET ALL CLASS VARIABLES def commit(self): #Commit variables to database >>u = User() >>u.name = 'Jason' >>u.email = '[email protected]' >>u.commit() So that each time User is called the variables are fresh. Thanks.

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  • iphone: caching and updating xml fields

    - by pJosh
    Thanks for your help. Here I have another question. I get the data through XMLParsing, now I want to store it in iphone's cache, and the XML Fields are updates every 12 hours.how can i check that XML Fields are change or not? and how can I store the data in iphone's cache memory so that evry it does not has to interact with web. Can anybody please help me???

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  • adding one time options to items

    - by rap-uvic
    Hello, I'm building an Event Registration site. For any given event, we'll have a handful of items to choose from. I have a table for these items. For each event we might have special options for users. For example, for one of the events new users get to buy an item which is not available to other users. This may not apply to all the events. For other events we might have some other restriction on items. I will obviously be checking this programmatically on application side. I would like to though, set up a column containing flag in the items table. But I don't find it feasible because this condition may only apply to one particular event. I don't want all the future items to have this column. What is a good approach to take in such a situation? Should I create a special "restrictions" table and just do a join? How would I handle this on the application side?

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  • MVC pattern and State Machine

    - by topright
    I think of a game as a state machine. Game States separate I/O processing, game logic and rendering into different classes: while (game_loop) { game->state->io_events(this); game->state->logic(this); game->state->rendering(); } You can easily change a game state in this approach. MVC separation works in more complex way: while (game_loop) { game->cotroller->io_events(this); game->model->logic(this); game->view->rendering(); } So changing Game States becomes error prone task (switch 3 MVC objects, not 1). What are practical ways of combining these 2 concepts?

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  • Best practices to store CreditCard information into DataBase

    - by Garis Suero
    In my country the online payments are not an old thing, the first time i saw a web application taking payments directly to a local bank account was last year. So, Im a newbie coding web payment system. My question is, what are the best practices to store creditcard information into the database... I have many ideas: encrypting the creditcard, database security restriction, etc. What have you done?

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  • Proper reconstitution of Aggregate objects in the Repository?

    - by Jebb
    Assuming that no ORM (e.g. Doctrine) is used inside the Repository, my question is what is the proper way of instantiating the Aggregate objects? Is it instantiating the child objects directly inside the Repository and just assign it to the Aggregate Root through its setters or the Aggregate Root is responsible of constructing its child entities/objects? Example 1: class UserRepository { // Create user domain entity. $user = new User(); $user->setName('Juan'); // Create child object orders entity. $orders = new Orders($orders); $user->setOrders($orders); } Example 2: class UserRepository { // Create user domain entity. $user = new User(); $user->setName('Juan'); // Get orders. $orders = $ordersDao->findByUser(1); $user->setOrders($orders); } whereas in example 2, instantiation of orders are taken care inside the user entity.

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  • Resources for Programmatic Rendering of Topology Maps

    - by bn
    Servus, Do you know of any frameworks, APIS, languages, or other resources that are well suited for drawing topology maps that allow a user to interact with objects on the map? I am not constrained by language choice and the program can be web-based, or stand-alone. I thought I would check before rolling my own. My goal is not to draw cartographic maps, but more like this picture: http://www.fineconnection.com/files/images/GraphicalNM.PNG, or if you are familiar with Edward Tufte's books, the data-visualization mechanisms he describes such as a map of a metro or subway. Also, if you have had any experience rendering these types of user interfaces or usage of underlying datastructures, I would be grateful to hear any thoughts you have on the subject, advice, any "gotchas." Thank you very for your time, -bn

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  • Tooltips with infinite timeout?

    - by romkyns
    I'm thinking of setting the timeout on all my tooltips in a WinForms application to infinity (or an extremely large value). The motivation is that it's annoying for the user if the tooltip disappears while I'm still reading it, without providing any extra value whatsoever as far as I can tell. Normally I wouldn't ask something like this on StackOverflow, but the overwhelming majority of all software sets timeouts on tooltips, so it makes me wonder whether perhaps there is some important consideration I'm missing? Or is this just an old convention that nobody gives further thought to? If you would hate infinite timeout as opposed to a short timeout, please explain why. (If you just think tooltips are a bad idea altogether then that's a separate consideration; this question is specifically about the infinite timeout.)

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  • Suggest Cassandra data model for an existing schema

    - by Andriy Bohdan
    Hello guys! I hope there's someone who can help me suggest a suitable data model to be implemented using nosql database Apache Cassandra. More of than I need it to work under high loads and large amounts of data. Simplified I have 3 types of objects: Product Tag ProductTag Product: key - string key name - string .... - some other fields Tag: key - string key name - unique tag words ProductTag: product_key - foreign key referring to product tag_key - foreign key referring to tag rating - this is rating of tag for this product Each product may have 0 or many tags. Tag may be assigned to 1 or many products. Means relation between products and tags is many-to-many in terms of relational databases. Value of "rating" is updated "very" often. I need to be run the following queries Select objects by keys Select tags for product ordered by rating Select products by tag order by rating Update rating by product_key and tag_key The most important is to make these queries really fast on large amounts of data, considering that rating is constantly updated.

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  • Create a Python User() class that both creates new users and modifies existing users

    - by ensnare
    I'm trying to figure out the best way to create a class that can modify and create new users all in one. This is what I'm thinking: class User(object): def __init__(self,user_id): if user_id == -1 self.new_user = True else: self.new_user = False #fetch all records from db about user_id self._populateUser() def commit(self): if self.new_user: #Do INSERTs else: #Do UPDATEs def delete(self): if self.new_user == False: return False #Delete user code here def _populate(self): #Query self.user_id from database and #set all instance variables, e.g. #self.name = row['name'] def getFullName(self): return self.name #Create a new user >>u = User() >>u.name = 'Jason Martinez' >>u.password = 'linebreak' >>u.commit() >>print u.getFullName() >>Jason Martinez #Update existing user >>u = User(43) >>u.name = 'New Name Here' >>u.commit() >>print u.getFullName() >>New Name Here Is this a logical and clean way to do this? Is there a better way? Thanks.

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