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  • SQL Server database change workflow best practices

    - by kubi
    The Background My group has 4 SQL Server Databases: Production UAT Test Dev I work in the Dev environment. When the time comes to promote the objects I've been working on (tables, views, functions, stored procs) I make a request of my manager, who promotes to Test. After testing, she submits a request to an Admin who promotes to UAT. After successful user testing, the same Admin promotes to Production. The Problem The entire process is awkward for a few reasons. Each person must manually track their changes. If I update, add, remove any objects I need to track them so that my promotion request contains everything I've done. In theory, if I miss something testing or UAT should catch it, but this isn't certain and it's a waste of the tester's time, anyway. Lots of changes I make are iterative and done in a GUI, which means there's no record of what changes I made, only the end result (at least as far as I know). We're in the fairly early stages of building out a data mart, so the majority of the changes made, at least count-wise, are minor things: changing the data type for a column, altering the names of tables as we crystallize what they'll be used for, tweaking functions and stored procs, etc. The Question People have been doing this kind of work for decades, so I imagine there have got to be a much better way to manage the process. What I would love is if I could run a diff between two databases to see how the structure was different, use that diff to generate a change script, use that change script as my promotion request. Is this possible? If not, are there any other ways to organize this process? For the record, we're a 100% Microsoft shop, just now updating everything to SQL Server 2008, so any tools available in that package would be fair game.

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  • Why is it not good to use $_SESSION in Restful Implementations?

    - by keisimone
    Original Question: i read that for RESTful websites. it is not good to use $_SESSION. Why is it not good? how then do i properly authenticate users without looking up database all the time to check for the user's roles? I read that it is not good to use $_SESSION. http://www.recessframework.org/page/towards-restful-php-5-basic-tips I am creating a WEBSITE, not web service in PHP. and i am trying to make it more RESTful. at least in spirit. right now i am rewriting all the action to use Form tags POST and add in a hidden value called _method which would be "delete" for deleting action and "put" for updating action. however, i am not sure why it is recommended NOT to use $_SESSION. i would like to know why and what can i do to improve. To allow easy authorization checking, what i did was to after logging in the user, the username is stored in the $_SESSION. Everytime the user navigates to a page, the page would check if the username is stored inside $_SESSION and then based on the $_SESSION retrieves all the info including privileges from the database and then evaluates the authorization to access the page based on the info retrieved. Is the way I am implementing bad? not RESTful? how do i improve performance and security? Thank you.

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  • Can you have a Dynamic Data Field which consists of a list of fields?

    - by Telos
    This is a purely theoretical question (at least until I start trying to implement it) but here goes. I wrote a web form a long time ago which has a configurable section for getting information. Basically for some customers there are no fields, for other customers there are up to 20 fields. I got it working by dynamically creating the fields at just the right time in the page lifecycle and going through a lot of headaches. 2 years later, I need to make some pretty big updates to this web form and there are some nifty new technologies. I've worked with ASP.NET Dynamic Data just a bit and, well, I half-crazed plan just occurred to me: The Ticket object has a one-to-many relationship to ExtendedField, we'll call that relationship Fields for brevity. Using that, the idea would be to create a FieldTemplate that dynamically generated the list of fields and displayed it. The big questions here would probably be: 1) Can a single field template resolve to multiple web controls without breaking things? 2) Can dynamic data handle updating/inserting multiple rows in such a fashion? 3) There was a third question I had a few minutes ago, but coworkers interrupted me and I forgot. So now the third question is: what is the third question? So basically, does this sound like it could work or am I missing a better/more obvious solution?

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  • using volatile keyword

    - by sap
    As i understand, if we declare a variable as volatile, then it will not be stored in the local cache. Whenever thread are updating the values, it is updated to the main memory. So, other threads can access the updated value. But in the following program both volatile and non-volatile variables are displaying same value. The volatile variable is not updated for the second thread. Can anybody plz explain this why testValue is not changed. class ExampleThread extends Thread { private int testValue1; private volatile int testValue; public ExampleThread(String str){ super(str); } public void run() { if (getName().equals("Thread 1 ")) { testValue = 10; testValue1= 10; System.out.println( "Thread 1 testValue1 : " + testValue1); System.out.println( "Thread 1 testValue : " + testValue); } if (getName().equals("Thread 2 ")) { System.out.println( "Thread 2 testValue1 : " + testValue1); System.out.println( "Thread 2 testValue : " + testValue); } } } public class VolatileExample { public static void main(String args[]) { new ExampleThread("Thread 1 ").start(); new ExampleThread("Thread 2 ").start(); } } output: Thread 1 testValue1 : 10 Thread 1 testValue : 10 Thread 2 testValue1 : 0 Thread 2 testValue : 0

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  • asp.net mvc: What is the correct way to return html from controller to refresh select list?

    - by Mark Redman
    Hi, I am new to ASP.NET MVC, particularly ajax operations. I have a form with a jquery dialog for adding items to a drop-down list. This posts to the controller action. If nothing (ie void method) is returned from the Controller Action the page returns having updated the database, but obviously there no chnage to the form. What would be the best practice in updating the drop down list with the added id/value and selecting the item. I think my options are: 1) Construct and return the html manually that makes up the new <select> tag [this would be easy enough and work, but seems like I am missing something] 2) Use some kind of "helper" to construct the new html [This seems to make sense] 3) Only return the id/value and add this to the list and select the item [This seems like an overkill considering the item needs to be placed in the correct order etc] 4) Use some kind of Partial View [Does this mean creating additional forms within ascx controls? not sure how this would effect submitting the main form its on? Also unless this is reusable by passing in parameters(not sure how thats done) maybe 2 is the option?] UPDATE: Having looked around a bit, it seems that generating html withing the controller is not a good idea. I have seen other posts that render partialviews to strings which I guess is what I need and separates concerns (since the html bits are in the ascx). Any comments on whether that is good practice.

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  • Routing problem with calling a new method without an ID

    - by alkaloids
    I'm trying to put together a form_tag that edits several Shift objects. I have the form built properly, and it's passing on the correct parameters. I have verified that the parameters work with updating the objects correctly in the console. However, when I click the submit button, I get the error: ActiveRecord::RecordNotFound in ShiftsController#update_individual Couldn't find Shift without an ID My route for the controller it is calling looks like this looks like this: map.resources :shifts, :collection => { :update_individual => :put } The method in ShiftsController is this: def update_individual Shift.update(params[:shifts].keys, params[:shifts].values) flash[:notice] = "Schedule saved" end The relevant form parts are these: <% form_tag( update_individual_shifts_path ) do %> ... (fields for...) <%= submit_tag "Save" %> <% end %> Why is this not working? If I browse to the url: "http://localhost:3000/shifts/update_individual/5" (or any number that corresponds to an existing shift), I get the proper error about having no parameters set, but when I pass parameters without an ID of some sort, it errors out. How do I make it stop looking for an ID at the end of the URL?

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

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

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  • Is ADO.NET Entity framework database schema update possible ?

    - by fyasar
    Hi All I'm working on proof of concept application like crm and i need your some advice. My application's data layer completely dynamic and run onto EF 3.5. When the user update the entity, change relation or add new column to the database, first i'm planning make for these with custom classes. After I rebuild my database model layer with new changes during the application runtime. And my model layer tie with tightly coupled to my project for easy reflecting model layer changes (It connected to my project via interfaces and loading onto to application domain in the runtime). I need to create dynamic entities, create entity relations and modify them during the runtime after that i need to create change database script for updating database schema. I know ADO.NET team says "we will be able to provide this property in EF 4.0", but i don't need to wait for them. How can i update database changes during the runtime via EF 3.5 ? For example, i need to create new entity or need to change some entity schema, add new properties or change property types after than how can apply these changes on the physical database schema ? Any ideas ?

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  • Handling data update/freshness issue in web-app in general (or GWT specifically)

    - by edwin.nathaniel
    In general, how do you guys handle user update/data freshness interaction with the user (UI issue) in web-apps? For example: Multi-users web-app (like project management) Login to a "virtual" space People can update project names, etc How to handle a situation such that: user-A and user-B load a project with title "Project StackOverflow" user-B updates the title to "Project StackExchange" user-A updates the title after user-B update operation to "Project Basecamp" The question I'm asking is from the user perspective (UI) and not about transactional operation. What do most people do in this situation? What would you do after user-B updates the title in user-A screen/view? What happened when user-A tries to update the title after user-B finished his/her update operation? do you inform user-A that the title has changed and he/she has to reload the page? do you go ahead and change the title and let user-B has old data? Do you do some sort of application-level "locking" mechanism? (if someone is updating, nobody else can?) Or fix the application workflow? (who has the access to be able to change things, etc). What would be the simplest solution, but at the same time not annoy the user with more dialog/warning messages. I've encountered this particular problem frequently in a GWT app specifically where domain models are being passed around and refreshing the whole app/client-side isn't the optimal solution in my mind (since it means the whole "loading"/initialization phase must be executed again in this specific environment). Maybe the answer is to stay away from GWT? :) Love to hear options, solutions, and advises from you guys. Thanks

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  • How to fix IllegalStateException error when trying to update a listview?

    - by Michael Vetrano
    Hi guys, I am trying to get this code to run, but I get an IllegalStateException when I run this code saying that the content of the listview wasn't notified, yet I have a notification upon updating the data. This is a custom listview adapter. Here is the relevant part of my code: class LoadingThread extends Thread { public void run() { int itemsOriginallyLoaded = 0; synchronized( items ) { itemsOriginallyLoaded = items.size(); } for( int i = itemsOriginallyLoaded ; i < itemsToLoad ; ++i ) { Log.d( LOG_TAG, "Loading item #"+i ); //String item = "FAIL"; //try { String item = "FAIL"; try { item = stockGrabber.getStockString(dataSource.get(i)); } catch (ApiException e) { Log.e(LOG_TAG, "Problem making API request", e); } catch (ParseException e) { Log.e(LOG_TAG, "Problem parsing API request", e); } //} catch (ApiException e) { // Log.e(TAG, "Problem making API request", e); //} catch (ParseException e) { // Log.e(TAG, "Problem parsing API request", e); //} synchronized( items ) { items.add( item ); } itemsLoaded = i+1; uiHandler.post( updateTask ); Log.d( LOG_TAG, "Published item #"+i ); } if( itemsLoaded >= ( dataSource.size() - 1 ) ) allItemsLoaded = true; synchronized( loading ) { loading = Boolean.FALSE; } } } class UIUpdateTask implements Runnable { public void run() { Log.d( LOG_TAG, "Publishing progress" ); notifyDataSetChanged(); } }

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  • Best strategy for synching data in iPhone app

    - by iamj4de
    I am working on a regular iPhone app which pulls data from a server (XML, JSON, etc...), and I'm wondering what is the best way to implement synching data. Criteria are speed (less network data exchange), robustness (data recovery in case update fails), offline access and flexibility (adaptable when the structure of the database changes slightly, like a new column). I know it varies from app to app, but can you guys share some of your strategy/experience? For me, I'm thinking of something like this: 1) Store Last Modified Date in iPhone 2) Upon launching, send a message like getNewData.php?lastModifiedDate=... 3) Server will process and send back only modified data from last time. 4) This data is formatted as so: <+><data id="..."></data></+> // add this to SQLite/CoreData <-><data id="..."></data></-> // remove this <%><data id="..."><attribute>newValue</attribute></data></%> // new modified value I don't want to make <+, <-, <%... for each attribute as well, because it would be too complicated, so probably when receive a <% field, I would just remove the data with the specified id and then add it again (assuming id here is not some automatically auto-incremented field). 5) Once everything is downloaded and updated, I will update the Last Modified Date field. The main problem with this strategy is: If the network goes down when I am updating something = the Last Modified Date is not yet updated = next time I relaunch the app, I will have to go through the same thing again. Not to mention potential inconsistent data. If I use a temporary table for update and make the whole thing atomic, it would work, but then again, if the update is too long (lots of data change), the user has to wait a long time until new data is available. Should I use Last-Modified-Date for each of the data field and update data gradually?

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  • How can I map stored procedure result into a custom class with linq-to-sql?

    - by Remnant
    I have a stored procedure that returns a result set (4 columns x n Rows). The data is based on multiple tables within my database and provides a summary for each department within a corporate. Here is sample: usp_GetDepartmentSummary DeptName EmployeeCount Male Female HR 12 5 7 etc... I am using linq-to-sql to retrieve data from my database (nb - have to use sproc as it is something I have inherited). I would like to call the above sproc and map into a department class: public class Department { public string DeptName {get; set;} public int EmployeeCount {get; set;} public int MaleCount {get; set;} public int FemaleCount {get; set;} } In VS2008, I can drag and drop my sproc onto the methods pane of the linq-to-sql designer. When I examine the designer.cs the return type for this sproc is defined as: ISingleResult<usp_GetDepartmentSummaryResult> What I would like to do is amend this somehow so that it returns a Department type so that I can pass the results of the sproc as a strongly typed view: <% foreach (var dept in Model) { %> <ul> <li class="deptname"><%= dept.DeptName %></li> <li class="deptname"><%= dept.EmployeeCount %></li> etc... Any ideas how to achieve this? NB - I have tried amending the designer.cs and dbml xml file directly but with limited success. I admit to being a little out of my depth when it comes to updating those files directly and I am not sure it is best practice? Would be good to get some diretion. Thanks much

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  • Nhibernate fires SQL commands

    - by Chris
    Hi all, when updating an entity A, NHibernate also send an SQL update command for some other entity B. A and B are not related. Just before saving entity A, the parent of entity B is loaded via a SQLQuery. Then, when accessed, B is lazy loaded (part of a collection). If I save entity A an update statement for entity B is generated as well. How can that be, that when saving an entity, another entity loaded before but is not related to the entity saved, is updated as well?! Can I somehow track where the update comes from? Btw. I am using an save event listener. Could it be that this is always triggered for entity loaded, even though they are not saved explicitly? public class EntitySaveEventListener : NHibernate.Event.Default.DefaultSaveEventListener { protected override object PerformSaveOrUpdate(SaveOrUpdateEvent e) { //auditing return base.PerformSaveOrUpdate(e); } } Update (sorry for providing not enough info): I tracked it down a bit. A select stateement on a entity called address is executed (is it lazy loaded by a parent). Then I create a new entity called Request. Right before saving this entity a session flush is called which updates the address, even though I did not call save or update on the address. Address is a collection within Request. <class name="Request" table="Request"> <bag name="addresses" access="field" cascade="all-delete-orphan" where="IsDeleted = 0"> <key column="RequestId"/> <one-to-many class="Address"/> </bag> ... // address is fetched only NHibernate.SQL: 2010-02-17 11:47:21,306 [21] DEBUG NHibernate.SQL [(null)] - SELECT addresses0_.RequestId as ServiceP8_3_, .... // session flushed here // address is updated NHibernate.SQL: 2010-02-17 11:47:34,306 [21] DEBUG NHibernate.SQL [(null)] - Batch commands: command 0:UPDATE Address SET Street = @p0, ..... Would the address be updated automatically when it is manipulated somehow even though it is not explicitly saved via it's parent (cascade)?

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  • How to pass dynamic values using MVC AJax.BeginForm

    - by Arthur
    I'm using MVC and AJax.BeginForm to do some ajax updating of my page. The BeginForm code looks something like: using (Ajax.BeginForm("HandleCrop", "Card", new { accept = true, id = Model.ImageUpload.ID, file = Model.ImageUpload.File, imageCropX = Model.CropInfo.X, imageCropY = Model.CropInfo.Y, imageCropWidth = Model.CropInfo.Width, imageCropHeight = Model.CropInfo.Height }, new AjaxOptions { HttpMethod = "POST", OnComplete = "ConfirmCompleted", OnSuccess = "ReloadUpload", OnFailure = "Failure" }, null)) The Model.CropInfo is being put in as hidden fields like so: <%=Html.HiddenFor(m => m.CropInfo.X) %> <%=Html.HiddenFor(m => m.CropInfo.Y) %> <%=Html.HiddenFor(m => m.CropInfo.Width) %> <%=Html.HiddenFor(m => m.CropInfo.Height) %> However, these values are being dynamically modified by some client side javascript, and these values need to be posted through the Ajax call back to the server. The above code will obviously not work as the imageCrop.. parameters in the Ajax form are being filled when the page is rendered (therefore being all 0). My question is: what is the correct way to approach this situation?

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  • Is ADO.NET Entity framework database schema update possible?

    - by fyasar
    I'm working on proof of concept application like crm and i need your some advice. My application's data layer completely dynamic and run onto EF 3.5. When the user update the entity, change relation or add new column to the database, first i'm planning make for these with custom classes. After I rebuild my database model layer with new changes during the application runtime. And my model layer tie with tightly coupled to my project for easy reflecting model layer changes (It connected to my project via interfaces and loading onto to application domain in the runtime). I need to create dynamic entities, create entity relations and modify them during the runtime after that i need to create change database script for updating database schema. I know ADO.NET team says "we will be able to provide this property in EF 4.0", but i don't need to wait for them. How can i update database changes during the runtime via EF 3.5 ? For example, i need to create new entity or need to change some entity schema, add new properties or change property types after than how can apply these changes on the physical database schema ? Any ideas ?

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  • Angular ng-style not changing with property

    - by ganaraj
    For the life of me I cant seem to figure out why the style property is not getting updated. In my larger application it seems to work fine. http://jsfiddle.net/ganarajpr/C2hRa/4/ Here is a fiddle which shows the issue I am currently facing. You will notice that the width and height are getting updated in the div when you change the input. But the style itself doesnt seem to be updating. Anyone can tell me what I am doing wrong here? I have tried all the following scenarios using $scope.$apply.. - Throws an error stating $apply already in progress.. $rootScope.$apply - same as above. Setting another variable in a service which is $watched in the other controller. - no change seen. It would be really cool if someone can get me an answer to this. Also would be really happy if you can tell me why exactly it is not getting updated.

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  • Excel and SQL, order by help

    - by perlnoob
    Im stuck in Excel 2007, running a query, it worked until I wanted to add a 2nd row containing "field 2". Select "Site Updates"."Posted By", "Site Uploaded"."Site Upload Date" From site_info.dbo."Site Updates" Where ("Site Updates"."Posted By") AND "Site Uploaded"."Site Upload Date">={ts '2010-05-01 00:00:00'}), ("Site Location"='Chicago') Union all Select "Site Updates"."Posted By", "Site Uploaded"."Site Upload Date" From site_info.dbo."Site Updates" Where ("Site Updates"."Posted By") AND "Site Uploaded"."Site Upload Date">={ts '2010-05-01 00:00:00'}), ("Site Location"='Denver') Order By "Site Location" ASC; Basically I want 2 different cells for the locations, example name - Chicago - denver user1 - 100 - 20 user2 - 34 - 1002 Right now for some odd reason, its combining it like: name - chicago user1 - 120 user2 - 1036 Please note updating to 2010 beta is not a viable option for me at this point. Any and all input that will help me is greatly apprecaited. I have read over http://www.techonthenet.com/sql/order_by.php however its not gotten me very far in this question. If you have another SQL resource you recomend for people trying to get their feet wet, I'd greatly apprecaite it. If it helps all the info is on the same table.

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  • populate textboxs with xml node attributes

    - by Doug
    I have Data.xml: <?xml version="1.0" encoding="utf-8" ?> <data> <album> <slide title="Autum Leaves" description="Leaves from the fall of 1986" source="images/Autumn Leaves.jpg" thumbnail="images/Autumn Leaves_thumb.jpg" /> <slide title="Creek" description="Creek in Alaska" source="images/Creek.jpg" thumbnail="images/Creek_thumb.jpg" /> </album> </data> I'd like to be able to edit the attributes of each Slide node via GridView (that has a "Select" column added.) And so far I have: protected void GridView1_SelectedIndexChanged(object sender, EventArgs e) { int selectedIndex = GridView1.SelectedIndex; LoadXmlData(selectedIndex); } private void LoadXmlData(int selectedIndex) { XmlDocument xmldoc = new XmlDocument(); xmldoc.Load(MapPath(@"..\photo_gallery\Data.xml")); XmlNodeList nodelist = xmldoc.DocumentElement.ChildNodes; XmlNode xmlnode = nodelist.Item(selectedIndex); titleTextBox.Text = xmlnode.Attributes["title"].InnerText; descriptionTextBox.Text = xmlnode.Attributes["description"].InnerText; sourceTextBox.Text = xmlnode.Attributes["source"].InnerText; thumbTextBox.Text = xmlnode.Attributes["thumbnail"].InnerText; The code for LoadXmlData is just a guess on my part - I'm new to working with xml in this way. I'd like have the user to slected the row from the gridview, then populate a set of text boxes with each slide attributed for updating back to the Data.xml file. The error I'm getting is "Object reference not set to an instance of an object" at the line: titleTextBox.Text = xmlnode.Attributes["@title"].InnerText; - so I'm not reaching the attribute "title" of the slide node. Thanks for any ideas you may have.

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  • SSIS - Bulk Update at Database Field Level

    - by Adam
    Hello, Here's our mission: Receive files from clients. Each file contains anywhere from 1 to 1,000,000 records. Records are loaded to a staging area and business-rule validation is applied. Valid records are then pumped into an OLTP database in a batch fashion, with the following rules: If record does not exist (we have a key, so this isn't an issue), create it. If record exists, optionally update each database field. The decision is made based on one of 3 factors...I don't believe it's important what those factors are. Our main problem is finding an efficient method of optionally updating the data at a field level. This is applicable across ~12 different database tables, with anywhere from 10 to 150 fields in each table (original DB design leaves much to be desired, but it is what it is). Our first attempt has been to introduce a table that mirrors the staging environment (1 field in staging for each system field) and contains a masking flag. The value of the masking flag represents the 3 factors. We've then put an UPDATE similar to... UPDATE OLTPTable1 SET Field1 = CASE WHEN Mask.Field1 = 0 THEN Staging.Field1 WHEN Mask.Field1 = 1 THEN COALESCE( Staging.Field1 , OLTPTable1.Field1 ) WHEN Mask.Field1 = 2 THEN COALESCE( OLTPTable1.Field1 , Staging.Field1 ) ... As you can imagine, the performance is rather horrendous. Has anyone tackled a similar requirement? We're a MS shop using a Windows Service to launch SSIS packages that handle the data processing. Unfortunately, we're pretty much novices at this stuff.

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  • Monotouch threads, GC, WCF

    - by cvista
    Hi This is a question about best practices i guess but it applies directly to my current MT project. I'm using WCF services to communicate with the server. To do this i do the following: services.MethodToCall(params); and the asynch: services.OnMethodToCallCompleted += delegate{ //do stuff and ting }; This can lead to issues if you're not careful in that variables defined within the scope of the asynch callback can sometimes be cleaned up by the gc and this can cause crashes. So - I am making it a practice to declare these outside of the scope of the callback unless I am 100% sure they are not needed. Now - when doing stuff and ting implies changing the ui - i wrap it all in an InvokeOnMainThread call. I guess wrapping everything in this would slow the main thread down and rubbish the point of having multi threads. Even though I'm being careful about all this i am still getting crashes and I have no idea why! I am certain it has something to do with threads, scope and all that. Now - the only thing I can think of outside of updating the UI that may need to happen inside of InvokeOnMainThread is that I have a singleton 'Database' class. This is based on the version 5 code from this thread http://www.yoda.arachsys.com/csharp/singleton.html So now if the service method returns data that needs to be added/updated to the Database class -I also wrap this inside an InvokeOnMainThread call. Still getting random crashes. So... My question is this: I am new to thick client dev - I'm coming from a web dev perspective where we don't need to worry about threads so much :) Aside from what I have mentioned -are there any other things I should be aware of? Is the above stuff correct? Or am i miss-understanding something? Cheers w://

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  • What is the preferred way to update database schemas in multiple production environments

    - by rmarimon
    I am about to install some 20 servers with the same web application in multiple locations connected to their own local database. I will be updating the web applications remotely (perhaps using debian's package manager) and I'm sure will eventually need to update the database schemas. Since each server could be eventually be using a different release of the web application, I need a way to apply the incremental changes to the servers. I'm thinking something like this. Let's start with database.schema.1 as the original release of the database and assume this number increases with each new version of the schema. I eventually could end up with database.schema.17 as the current release. For a new installation this would be the schema to install. It seems to me that I would need consecutive translations like database.translation.1.2 which would convert database.schema.1 into database.schema.2, database.translation.2.3 to convert from 2 to 3 and so on until 17. It seems that whenever I change a schema I need to alter the database but perhaps I need to run some script to update the data which might be done with SQL but might require an external non sql script. What is the appropriate way to organize all these files? What is the automatic way to apply those upgrades to the schema? Where do I store the current version number of the schema?

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  • Rails running multiple delayed_job - lock tables

    - by pepernik
    Hey. I use delayed_job for background processing. I have 8 CPU server, MySQL and I start 7 delayed_job processes RAILS_ENV=production script/delayed_job -n 7 start Q1: I'm wondering is it possible that 2 or more delayed_job processes start processing the same process (the same record-row in the database delayed_jobs). I checked the code of the delayed_job plugin but can not find the lock directive in a way it should be. I think each process should lock the database table before executing an UPDATE on lock_by column. They lock the record simply by updating the locked_by field (UPDATE delayed_jobs SET locked_by...). Is that really enough? No locking needed? Why? I know that UPDATE has higher priority than SELECT but I think this does not have the effect in this case. My understanding of the multy-threaded situation is: Process1: Get waiting job X. [OK] Process2: Get waiting jobs X. [OK] Process1: Update locked_by field. [OK] Process2: Update locked_by field. [OK] Process1: Get waiting job X. [Already processed] Process2: Get waiting jobs X. [Already processed] I think in some cases more jobs can get the same information and can start processing the same process. Q2: Is 7 delayed_jobs a good number for 8CPU server? Why yes/not. Thx 10x!

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  • Python unittest (using SQLAlchemy) does not write/update database?

    - by Jerry
    Hi, I am puzzled at why my Python unittest runs perfectly fine without actually updating the database. I can even see the SQL statements from SQLAlchemy and step through the newly created user object's email -- ...INFO sqlalchemy.engine.base.Engine.0x...954c INSERT INTO users (user_id, user_name, email, ...) VALUES (%(user_id)s, %(user_name)s, %(email)s, ...) ...INFO sqlalchemy.engine.base.Engine.0x...954c {'user_id': u'4cfdafe3f46544e1b4ad0c7fccdbe24a', 'email': u'[email protected]', ...} > .../tests/unit_tests/test_signup.py(127)test_signup_success() -> user = user_q.filter_by(user_name='test').first() (Pdb) n ...INFO sqlalchemy.engine.base.Engine.0x...954c SELECT users.user_id AS users_user_id, ... FROM users WHERE users.user_name = %(user_name_1)s LIMIT 1 OFFSET 0 ...INFO sqlalchemy.engine.base.Engine.0x...954c {'user_name_1': 'test'} > .../tests/unit_tests/test_signup.py(128)test_signup_success() -> self.assertTrue(isinstance(user, model.User)) (Pdb) user <pweb.models.User object at 0x9c95b0c> (Pdb) user.email u'[email protected]' Yet at the same time when I login to the test database, I do not see the new record there. Is it some feature from Python/unittest/SQLAlchemy/Pyramid/PostgreSQL that I'm totally unaware of? Thanks. Jerry

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  • Does SetFileBandwidthReservation affect memory-mapped file performance?

    - by Ghostrider
    Does this function affect Memory-mapped file performance? Here's the problem I need to solve: I have two applications competing for disk access: "reader" and "updater". Whole system runs on Windows Server 2008 R2 x64 "Updater" constantly accesses disk in a linear manner, updating data. They system is set up in such a way that updater always has infinite data to update. Consider that it is constantly approximating a solution of a huge set of equations that takes up entire 2TB disk drive. Updater uses ReadFile and WriteFile to process data in a linear fashion. "Reader" is occasionally invoked by user to get some pieces of data. Usually user would read several 4kb blocks from the drive and stop. Occasionally user needs to read up to 100mb sequentially. In exceptional cases up to several gigabytes. Reader maps files to memory to get data it needs. What I would like to achieve is for "reader" to have absolute priority so that "updater" would completely stop if needed so that "reader" could get the data user needs ASAP. Is this problem solvable by using SetPriorityClass and SetFileBandwidthReservation calls? I would really hate to put synchronization login in "reader" and "updater" and rather have the OS take care of priorities.

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  • retrieving multiple versions through API through hbase

    - by sammy
    hello , this is a continuation of my previous question where id used hbase shell.. http://stackoverflow.com/questions/3024417/facing-problems-while-updating-rows-in-hbase i tried the same with API.. im not able to figure out how to retrieve all versions , iterate and print their values for a specific row... i've spending hours reading... please help me out... Scan s = new Scan(Bytes.toBytes("row1")); s.addColumn(Bytes.toBytes("column"),Bytes.toBytes("address")); SETTING RANGE FOR THE VERSIONS s.setTimeRange(0L,6L); ResultScanner scanner = table.getScanner(s); for (Result r : scanner) { for(KeyValue kv : r.sorted()) { System.out.println("To"+kv.getTimestamp()); System.out.println("from "+Bytes.toString(kv.getKey())); System.out.println("To "+Bytes.toString(kv.getValue())); } scanner.close(); } here im intending to print all versions of the column..... but it gives the most recent one... im stuck here...

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