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Πρόσφατες Δημοσιεύσεις
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I will be writing a new series of posts about the new T-SQL functions that are available to us in SQL Server 2012. In this rather sort post I will demonstrate with a hands-on examples how to use 3 new conversion functions in SQL Server 2012, PARSE, TRY_CONVERT and TRY_PARSE.( read more )...
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I will be writing a new series of posts about the new T-SQL functions that are available to us in SQL Server 2012. In this rather sort post I will demonstrate with a hands-on examples how to use 2 new logical functions in SQL Server 2012, CHOOSE and IIF. ( read more )...
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If you use TimeUpDown control from Silverlight Toolkit in your XAML like below (copy pasting from CaptionGrid at ClipFlair source): <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" > <DataTemplate x:Key="StartTimeCellTemplate"> <TextBlock Margin="4" Text="{Binding Begin}" /> </DataTemplate> <DataTemplate x:Key="StartTimeCellEditTemplate"> <!-- <TextBox Margin="4" Text="{Binding Begin, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=true}" /> --> <input:TimeUpDown Format="hh:mm:ss" Value="{Binding Begin, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=true}" /> </DataTemplate> … </ResourceDictionary> [...]...
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In this post I will demonstrate how to install SQL Server 2012 in your machine. I had no intention of writing such a post but I installed SQL Server 2012 Developer edition a few weeks back in my Windows 7 Ultimate SP1 laptop and it worked just fine.Then I thought it would be a good idea to write a post like that since a lot of people install the latest version of SQL Server. ( read more )...
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Διαβάζοντας το τελευταίο άρθρο του Jonathan Kehayias διαπίστωσα ότι έχω πολύ καιρό να γράψω κάτι για τα internals του SQL Server. Μέσα στο άρθρο αυτό του Jonathan υπάρχουν αναφορές σε κάποια ειδικά pages που υπάρχουν σε κάθε database στον SQL Server. Με αφορμή αυτό αποφάσισα να γράψω το post αυτό και να αναφερθώ σε όλα αυτά το special pages. Page structure and page offset Πριν ξεκινήσω όμως την αναφορά μου σε αυτά θα πρέπει να είμαι σίγουρος ότι όλοι γνωρίζουμε ότι κάθε data file σε μια SQL Server database δομείτε εσωτερικά σε pages των 8ΚΒ. Σε αυτά αποθηκεύονται τα δεδομένα του SQL Server. Ένα page έχει τον page header που είναι 96 bytes και το offset array το οποίο βρίσκεται στο τέλος του page, είναι 36 bytes και παρέχει τους δείκτες (pointers) στο byte location της αρχής της κάθε γραμμής (record) που είναι στην συγκεκριμένη σελίδα. Αυτό είναι αποθηκευμένο αντίστροφα πάνω στην σελίδα δηλαδή το offset του πρώτου record είναι στο τέλος του συγκεκριμένου array το δεύτερο είναι προτελευταίο κ.ο.κ. Το υπόλοιπο τμήμα...
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When you tell the Visual Studio IDE to generate a web project (instead of just using an autogenerated page) for a Silverlight project, it creates a project named SilverlightAppName.Web with a SilverlightAppNameTestPage.aspx (ASP.net) and an SilverlightAppNameTestPage.html. Either one can be served from a web server (obviously the .aspx one from IIS or any web server [...]...
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Following up on a note about Visual Studio 2010 crashing at my previous post, this is the XAML that crashes VS2010 when opened up in a Silverlight project: <UserControl x:Class="SilverlightApplication1.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <UserControl.Resources> <ResourceDictionary> <Style x:Key="MyStyle" TargetType="StackPanel"> <Setter Property="Margin" Value="0,5,0,5" [...]...
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While adding some properties to the back panels of ClipFlair windows, I came upon the issue of how to space items in a StackPanel. A Padding property is missing from multiple item containers (only single content controls have such), but a nice solution is described at: http://stackoverflow.com/questions/932510/how-do-i-space-out-the-child-elements-of-a-stackpanel Sergey Aldoukhov suggested there (WPF example): Use Margin [...]...
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Last week I attended TechEd Europe 2012 held in Amsterdam. This was my 6th TechEd but my first time in Amsterdam and the experience was, as always, great. Although there weren’t any announcements (the announcements were made earlier this month) most of the content presented had something new to teach, a small surprise for every [...]...
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Οι περισσότεροι είστε σε κάποιον παραθαλάσσιο μέρος και καλά κάνετε. Παρόλα αυτά όμως τα SQL Saturday Nights ακόμα δεν έχουν τελειώσει, απλά αντί να σας βάζω σε διαδικασίες να τα παρακολουθήσετε live αποφάσισα να φτιάξω ένα απόψε καθώς θέλω να αναδείξω ένα θέμα το οποίο οι περισσότεροι δεν γνωρίζετε ή το γνωρίζετε λίγο ή ακόμα και για αυτούς που το γνωρίζουν δεν είναι κακό να το ξαναδούν. Αφορά τον αριθμό των VLFs (Virtual Log Files) που έχει ένα transaction log σε μία database στον SQL Server και πως όταν αυτός ο αριθμός είναι αρκετά μεγάλος επηρεάζει την απόδοση μιας datatase. περισσότερα...
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In this post I would like to talk about a new security enhancement that was introduced in SQL Server 2012,user defined server roles.As we all know we had (and still have in SQL Server 2012) user defined database roles for database level permissions.In the latest version of SQL Server we can have custom – user defined server roles for server level permissions.Basically for a server-level principal we can grant server-level permissions with a mix of GRANT and DENY permissions. ( read more )...
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In this post I would like to demonstrate with a hands-on example how to backup and restore the tail of the transaction log.In this post I will also demonstrate how to take full and differential backups and how to restore them. I will also talk about the various SQL Server backup types, recovery models and how these models affect our backup and restore strategy. ( read more )...
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During the development of ClipFlair (currently at Alpha1-internal version), I’ve been doing lots of research, hunting for information (documentation, related discussion threads, useful download links) needed when writing and refactoring source code etc. I have tried to organize these links as (Windows) Internet shortcut files into folders. They do need some further restructuring, but they [...]...
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Σαν παλαιός developer έχω νιώσει αρκετά καλά στο πετσί μου ότι ο όμορφα γραμμένος κώδικας όσο χάλια και αν είναι πάντα βοηθάει στην ανάγνωση του με αποτέλεσμα να εξυπηρετεί αρκετά τόσο στο debugging αυτού όσο και στο refactoring και extension. Αρκετές φορές ακόμα έχω δεχθεί ερώτηση για αυτό τόσο στον χώρο εργασίας μου όσο και κατά την διάρκεια των σεμιναρίων που κάνω. Αν και βαθιά πιστεύω ότι αυτό είναι κάτι το οποίο είναι θέμα που πρέπει να ορισθεί σε επίπεδο προσωπικό και ομάδας εργασίας εντούτοις υπάρχουν κάποιοι βασικοί κανόνες που θα μπορούσαμε να χρησιμοποιήσουμε καθώς είναι χρόνια δοκιμασμένοι και δεν χρειάζεται να ανακαλύψουμε ξανά τον τροχό από την αρχή. Φυσικά σε αυτούς μπορούμε να βάλουμε και τις προσωπικές μας πινελιές που μας εξυπηρετούν ή ταιριάζουν την ιδιοσυγκρασία μας. read more...
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Following up on my last post: http://zoomicon.wordpress.com/2012/07/04/how-to-compile-code-that-uses-wpf-decorator-type-in-silverlight/ I’m copying from a mental note I added to: http://stackoverflow.com/questions/4936941/using-a-using-alias-class-with-generic-types/11334359: As shown at: http://msdn.microsoft.com/en-us/library/sf0df423.aspx and http://msdn.microsoft.com/en-us/library/c3ay4x3d%28VS.80%29.aspx you can do: using gen = System.Collections.Generic; using GenList = System.Collections.Generic.List<int>; and then use gen::List<int> x = new gen::List<int>; or GenList x = new GenList(); However: you have to replicate those using [...]...
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At ClipFlair I’m using a modified version of FloatingWindow control, where I try to make the WPF and Silverlight flavours of the original control share as much code as possible (this is work in progress currently, hoping to eventually have the WPF and Silverlight projects both link to the same source files [this is currently [...]...
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A couple of weeks back I had the chance to speak at a Microsoft Dev Day event about all the cool new features announced for windows azure June release and especially those that had to do with IaaS. The room was packed and everyone seemed very interested on these long awaited new features. I had [...]...
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I was hoping C# would someday add static extension support for constructors too (apart from classic methods), that would help a lot in source-level compatibility layers (for example at my WPF_Compatibility project for WPF syntax in Silverlight, which one can find under the ClipFlair source base). However, according to : http://mrpmorris.blogspot.gr/2007/01/net-calling-base-constructors-in-c.html Anders Hejlsberg (father of [...]...
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I just had some big trouble troubleshooting the Visual Studio / XAML compiler error message: The tag XXX does not exist in XML namespace ‘clr-namespace:YYY’ It turned out this occurred because I had a Silverlight library with Assembly name X and default namespace X (at properties pane), but was using it from a demo project [...]...
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In the previous post we have seen how we create scheduled and periodic tile notifications with Javascript for metro applications. In this post we will cover push notifications . Push notifications do not require from your app to tell the OS that it has to query a service at specific time intervals as periodic notifications do. They rely on the fact that an external service can actually change the tile when it sees fit (hence the “push” name). Such notifications cover scenarios like having an application that monitors stock prices and the user specifying that he wants to be informed when the price of a stock falls under a specific value. The push notification will change the tile’s appearance when the premise is fulfilled. Note that a periodic notification would not suit in this case unless the user could accept a possible maximum half hour delay of the delivery of the notification. Push notifications work as follows: Your metro app requests from the device a specific URI which uniquely defines the combination...
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This post will cover the main aspects of using Tile Notifications in a Metro-Style application. The only topic that will not be covered is “Push Notifications” since those deserve a post on their own and will follow in the near future. So what are “Tile Notifications”? Well as you already know, each Metro-Style application has its own tile which appears in the start screen. This tile is either a “square” or a “wide” one as depicted in the following figure: The user gets to choose from the “start menu” application bar which one of the two will be shown. You specify in your application that you support both by providing in the package.appxmanifest file (Application UI tab) a image for both the Logo and the Wide logo property: It is important that you provide the wide version of the logo cause otherwise your application will not be able to appear as “wide” in the start menu and that option will not exist for the user in the application bar. Having done this, you may use the tile to make...
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In this post I would like to demonstrate with a hands-on example that is not always possible to restore a database to any Edition of SQL Server.We assume of course that the version of SQL Server remains the same. In my machine I have various instances of SQL Server running.I have an instance of SQL Server 2008 R2 Developer Edition and an instance of SQL Server 2008 R2 Standard edition.( read more )...
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In this post I would like to talk about a common issue that confuses SQL Server DBAs and developers.RecentlyI had to deploy an ASP.Net web site from the development server to the live production server.The database server on the deployment server was SQL Server 2008 R2.The hosting provider could only provide us with a SQL Server 2008 database server.Most of my colleagues thought there was no problem with that.I had a different opinion.Ι know that this is not possible. ( read more )...
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At LvS (the opensource application of LeViS), I’ve been using this (VB.net) code to set the UI language (for example to Greek): Thread.CurrentThread.CurrentUICulture = CultureInfo.GetCultureInfo("el") Others seem to have been using (C# – that’s why there is a trailing semicolon): Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("el"); assuming System.Globalization and System.Threading namespaces have been imported. However, now that I’m [...]...
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