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  • Oracle Insert via Select from multiple tables where one table may not have a row

    - by Mikezx6r
    I have a number of code value tables that contain a code and a description with a Long id. I now want to create an entry for an Account Type that references a number of codes, so I have something like this: insert into account_type_standard (account_type_Standard_id, tax_status_id, recipient_id) ( select account_type_standard_seq.nextval, ts.tax_status_id, r.recipient_id from tax_status ts, recipient r where ts.tax_status_code = ? and r.recipient_code = ?) This retrieves the appropriate values from the tax_status and recipient tables if a match is found for their respective codes. Unfortunately, recipient_code is nullable, and therefore the ? substitution value could be null. Of course, the implicit join doesn't return a row, so a row doesn't get inserted into my table. I've tried using NVL on the ? and on the r.recipient_id. I've tried to force an outer join on the r.recipient_code = ? by adding (+), but it's not an explicit join, so Oracle still didn't add another row. Anyone know of a way of doing this? I can obviously modify the statement so that I do the lookup of the recipient_id externally, and have a ? instead of r.recipient_id, and don't select from the recipient table at all, but I'd prefer to do all this in 1 SQL statement.

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  • Entity Framework does not map 2 columns from a SqlQuery calling a stored procedure

    - by user1783530
    I'm using Code First and am trying to call a stored procedure and have it map to one of my classes. I created a stored procedure, BOMComponentChild, that returns details of a Component with information of its hierarchy in PartsPath and MyPath. I have a class for the output of this stored procedure. I'm having an issue where everything except the two columns, PartsPath and MyPath, are being mapped correctly with these two properties ending up as Nothing. I searched around and from my understanding the mapping bypasses any Entity Framework name mapping and uses column name to property name. The names are the same and I'm not sure why it is only these two columns. The last part of the stored procedure is: SELECT t.ParentID ,t.ComponentID ,c.PartNumber ,t.PartsPath ,t.MyPath ,t.Layer ,c.[Description] ,loc.LocationID ,loc.LocationName ,CASE WHEN sup.SupplierID IS NULL THEN 1 ELSE sup.SupplierID END AS SupplierID ,CASE WHEN sup.SupplierName IS NULL THEN 'Scinomix' ELSE sup.SupplierName END AS SupplierName ,c.Active ,c.QA ,c.IsAssembly ,c.IsPurchasable ,c.IsMachined ,t.QtyRequired ,t.TotalQty FROM BuildProducts t INNER JOIN [dbo].[BOMComponent] c ON c.ComponentID = t.ComponentID LEFT JOIN [dbo].[BOMSupplier] bsup ON bsup.ComponentID = t.ComponentID AND bsup.IsDefault = 1 LEFT JOIN [dbo].[LookupSupplier] sup ON sup.SupplierID = bsup.SupplierID LEFT JOIN [dbo].[LookupLocation] loc ON loc.LocationID = c.LocationID WHERE (@IsAssembly IS NULL OR IsAssembly = @IsAssembly) ORDER BY t.MyPath and the class it maps to is: Public Class BOMComponentChild Public Property ParentID As Nullable(Of Integer) Public Property ComponentID As Integer Public Property PartNumber As String Public Property MyPath As String Public Property PartsPath As String Public Property Layer As Integer Public Property Description As String Public Property LocationID As Integer Public Property LocationName As String Public Property SupplierID As Integer Public Property SupplierName As String Public Property Active As Boolean Public Property QA As Boolean Public Property IsAssembly As Boolean Public Property IsPurchasable As Boolean Public Property IsMachined As Boolean Public Property QtyRequired As Integer Public Property TotalQty As Integer Public Property Children As IDictionary(Of String, BOMComponentChild) = New Dictionary(Of String, BOMComponentChild) End Class I am trying to call it like this: Me.Database.SqlQuery(Of BOMComponentChild)("EXEC [BOMComponentChild] @ComponentID, @PathPrefix, @IsAssembly", params).ToList() When I run the stored procedure in management studio, the columns are correct and not null. I just can't figure out why these won't map as they are the important information in the stored procedure. The types for PartsPath and MyPath are varchar(50).

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  • Faster way to convert from a String to generic type T when T is a valuetype?

    - by Kumba
    Does anyone know of a fast way in VB to go from a string to a generic type T constrained to a valuetype (Of T as Structure), when I know that T will always be some number type? This is too slow for my taste: Return DirectCast(Convert.ChangeType(myStr, GetType(T)), T) But it seems to be the only sane method of getting from a String -- T. I've tried using Reflector to see how Convert.ChangeType works, and while I can convert from the String to a given number type via a hacked-up version of that code, I have no idea how to jam that type back into T so it can be returned. I'll add that part of the speed penalty I'm seeing (in a timing loop) is because the return value is getting assigned to a Nullable(Of T) value. If I strongly-type my class for a specific number type (i.e., UInt16), then I can vastly increase the performance, but then the class would need to be duplicated for each numeric type that I use. It'd almost be nice if there was converter to/from T while working on it in a generic method/class. Maybe there is and I'm oblivious to its existence?

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  • How do I introspect on a SQL Server?

    - by MetaHyperBolic
    I have a server with a vendor application which is heavily database-reliant. I need to make some minor changes to the data in a few tables in the database in an automated fashion. Just INSERTs and UPDATEs, nothing fancy. Vendors being vendors, I can never be quite sure when they change the schema of a database during upgrade. To that end, how do I ask the SQL server, in some scriptable fashion, "Hey, does this table still exist? Yeah, cool, okay, but does it have this column? What's the data type and size on that? Is it nullable? Could you give me a list of tables? In this table, could you give me a list of columns? Any primary keys there?" I do not need to do this for the whole schema, only part of it, just a quick check of the database before I launch into things. We have Microsoft SQL Server 2005 on it currently, but it might easily move to Microsoft SQL Server 2008. I am probably not using the correct terminology when searching. I do know that ORM is not only too much overhead for this sort of thing, but also that I have no chance of pitching it to my coworkers.

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  • EF 4 Query - Issue with Multiple Parameters

    - by Brian
    Hello, A trick to avoiding filtering by nullable parameters in SQL was something like the following: select * from customers where (@CustomerName is null or CustomerName = @CustomerName) This worked well for me in LINQ to SQL: string customerName = "XYZ"; var results = (from c in ctx.Customers where (customerName == null || (customerName != null && c.CustomerName == customerName)) select c); But that above query, when in ADO.NET EF, doesn't work for me; it should filter by customer name because it exists, but it doesn't. Instead, it's querying all the customer records. Now, this is a simplified example, because I have many fields that I'm utilizing this kind of logic with. But it never actually filters, queries all the records, and causes a timeout exception. But the wierd thing is another query does something similarly, with no issues. Any ideas why? Seems like a bug to me, or is there a workaround for this? I've since switched to extension methods which works. Thanks.

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  • Unnecessary Redundancy with Tables.

    - by Stacey
    My items are listed as follows; This is just a summary of course. But I'm using a method shown for the "Detail" table to represent a type of 'inheritence', so to speak - since "Item" and "Downloadable" are going to be identical except that each will have a few additional fields relevant only to them. My question is in this design pattern. This sort of thing appears many, many times in our projects - is there a more intelligent way to handle it? I basically need to normalize the tables as much as possible. I'm extremely new to databases and so this is all very confusing to me. There are 5 items. Awards, Items, Purchases, Tokens, and Downloads. They are all very, very similar, except each has a few pieces of data relevant only to itself. I've tried to use a declaration field (like an enumerator 'Type' field) in conjunction with nullable columns, but I was told that is a bad approach. What I have done is take everything similar and place it in a single table, and then each type has its own table that references a column in the 'base' table. The problem occurs with relationships, or junctions. Linking all of these back to a customer. Each type takes around 2 additional tables to properly junction all of the data together- and as such, my database is growing very, very large. Is there a smarter practice for this kind of behavior? Item ID | GUID Name | varchar(64) Product ID | GUID Name | varchar(64) Store | GUID [ FK ] Details | GUID [FK] Downloadable ID | GUID Name | varchar(64) Url | nvarchar(2048) Details | GUID [FK] Details ID | GUID Price | decimal Description | text Peripherals [ JUNCTION ] ID | GUID Detail | GUID [FK] Store ID | GUID Addresses | GUID Addresses ID | GUID Name | nvarchar(64) State | int [FK] ZipCode | int Address | nvarchar(64) State ID | int Name | varchar(32)

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  • PHP Web Services - Nice try

    Thanks to the membership in the O'Reilly User Group Programme the Mauritius Software Craftsmanship Community (short: MSCC) recently received a welcome package with several book titles. Among them is the latest publication of Lorna Jane Mitchell - 'PHP Web Services: APIs for the Modern Web'. Following is the book review I put on Amazon: Nice try! Initially, I was astonished that a small book like 'PHP Web Services' would be able to cover all the interesting topics about APIs and Web Services, independently whether they are written in PHP or not. And unfortunately, the title isn't able to stand up to the readers (or at least my) expectations. Maybe as a light defense, there is no usual paragraph about the intended audience of that book, but still I have to admit that the first half (chapters 1 to 8) are well written and Lorna has her points on the various technologies. Also, the code samples in PHP are clean and easy to understand. With chapter 'Debugging Web Services' the book started to change my mind about the clarity of advice and the instructions on designing and developing good APIs. Eventually, this might be related to the fact that I'm used to other tools since years, like Telerik Fiddler as HTTP proxy in order to trace and inspect any kind of request/response handling. Including localhost monitoring, SSL certification acceptance, and the ability to debug mobile devices, especially iOS-based ones. Compared to Charles, Fiddler is available for free. What really got me off the hook is the following statement in chapter 10 about Service Type Decisions: "For users who have larger systems using technology stacks such as Java, C++, or .NET, it may be easier for them to integrate with a SOAP service." WHAT? A couple of pages earlier the author recommends to stay away from 'old-fashioned' API styles like SOAP (if possible). And on top of that I wonder why there are tons of documentation towards development of RESTful Web Services based on WebAPI. The ASP.NET stack clearly moves away from SOAP to JSON and REST since years! Honestly, as a software developer on the .NET stack this leaves a mixed feeling after all. As for the remaining chapters I simply consider them as 'blah blah' without any real value and lots of theoretical advice. Related to the chapter 13 about 'Documentation', I just had the 'pleasure' to write a C#-based client against a Java-based SOAP Web Service. Personally, I take the WSDL as the master reference in the first place and Visual Studio generates all the stub types involved in the communication. During the implementation and testing I came across a 'java.lang.NullPointerException' in various methods and for various method parameters. The WSDL and the generated types were declared as Nullable, so nothing to worry about, or? Well, I logged in a support ticket, and guess what was the response to that scenario? "The service definition in the WSDL is wrong, please refer to the documentation in order to use the methods and parameters correctly" - No comment! Lorna's title is a quick read and in some areas she has good advice on designing and implementing Web Services and APIs. But roughly 100 pages aren't enough to cover a vast topic like that. After all, nice try and I'm looking forward to an improved second edition. Honestly, I never thought that I would come across a poor review. In general, it's a good book but it clearly has a lack of depth, the PHP code samples are incomplete (closing tags missing), and there are too many assumptions and theoretical statements.

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  • Announcement: Employee Info Starter Kit (v5.0) is Released

    - by Mohammad Ashraful Alam
    Ever wanted to have a simple jQuery menu bound with ASP.NET web site map file? Ever wanted to have cool css design stuffs implemented on your ASP.NET data bound controls? Ever wanted to let Visual Studio generate logical layers for you, which can be easily tested, customized and bound with ASP.NET data controls? If your answers with respect to above questions are ‘yes’, then you will probably happy to try out latest release (v5.0) of Employee Starter Kit, which is intended to address different types of real world challenges faced by web application developers when performing common CRUD operations. Using a single database table ‘Employee’, the current release illustrates how to utilize Microsoft ASP.NET 4.0 Web Form Data Controls, Entity Framework 4.0 and Visual Studio 2010 effectively in that context. Employee Info Starter Kit is an open source ASP.NET project template that is highly influenced by the concept ‘Pareto Principle’ or 80-20 rule, where it is targeted to enable a web developer to gain 80% productivity with 20% of effort with respect to learning curve and production. This project template is titled as “Employee Info Starter Kit”, which was initially hosted on Microsoft Code Gallery and been downloaded 1, 50,000+ of copies afterword.  The latest version of this starter kit is hosted in Codeplex. Release Highlights User End Functional Specification The user end functionalities of this starter kit are pretty simple and straight forward that are focused in to perform CRUD operation on employee records as described below. Creating a new employee record Read existing employee records Update an existing employee record Delete existing employee records Architectural Overview Simple 3 layer architecture (presentation, business logic and data access layer) ASP.NET web form based user interface Built-in code generators for logical layers, implemented in Visual Studio default template engine (T4) Built-in Entity Framework entities as business entities (aka: data containers) Data Mapper design pattern based Data Access Layer, implemented in C# and Entity Framework Domain Model design pattern based Business Logic Layer, implemented in C# Object Model for Cross Cutting Concerns (such as validation, logging, exception management) Minimum System Requirements Visual Studio 2010 (Web Developer Express Edition) or higher Sql Server 2005 (Express Edition) or higher Technology Utilized Programming Languages/Scripts Browser side: JavaScript Web server side: C# Code Generation Template: T-4 Template Frameworks .NET Framework 4.0 JavaScript Framework: jQuery 1.5.1 CSS Framework: 960 grid system .NET Framework Components .NET Entity Framework .NET Optional/Named Parameters (new in .net 4.0) .NET Tuple (new in .net 4.0) .NET Extension Method .NET Lambda Expressions .NET Anonymous Type .NET Query Expressions .NET Automatically Implemented Properties .NET LINQ .NET Partial Classes and Methods .NET Generic Type .NET Nullable Type ASP.NET Meta Description and Keyword Support (new in .net 4.0) ASP.NET Routing (new in .net 4.0) ASP.NET Grid View (CSS support for sorting - (new in .net 4.0)) ASP.NET Repeater ASP.NET Form View ASP.NET Login View ASP.NET Site Map Path ASP.NET Skin ASP.NET Theme ASP.NET Master Page ASP.NET Object Data Source ASP.NET Role Based Security Getting Started Guide To see Employee Info Starter Kit in action is pretty easy! Download the latest version. Extract the file. From the extracted folder click the C# project file (Eisk.Web.csproj) to open it in Visual Studio 2010 Hit Ctrl+F5! The current release (v5.0) of Employee Info Starter Kit is properly packaged, fully documented and well tested. If you want to learn more about it in details, just check the following links: Release Home Page Installation Walkthrough Hand on Coding Walkthrough Technical Reference Enjoy!

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  • CLR via C# 3rd Edition is out

    - by Abhijeet Patel
    Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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  • Calculated Columns in Entity Framework Code First Migrations

    - by David Paquette
    I had a couple people ask me about calculated properties / columns in Entity Framework this week.  The question was, is there a way to specify a property in my C# class that is the result of some calculation involving 2 properties of the same class.  For example, in my database, I store a FirstName and a LastName column and I would like a FullName property that is computed from the FirstName and LastName columns.  My initial answer was: 1: public string FullName 2: { 3: get { return string.Format("{0} {1}", FirstName, LastName); } 4: } Of course, this works fine, but this does not give us the ability to write queries using the FullName property.  For example, this query: 1: var users = context.Users.Where(u => u.FullName.Contains("anan")); Would result in the following NotSupportedException: The specified type member 'FullName' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported. It turns out there is a way to support this type of behavior with Entity Framework Code First Migrations by making use of Computed Columns in SQL Server.  While there is no native support for computed columns in Code First Migrations, we can manually configure our migration to use computed columns. Let’s start by defining our C# classes and DbContext: 1: public class UserProfile 2: { 3: public int Id { get; set; } 4: 5: public string FirstName { get; set; } 6: public string LastName { get; set; } 7: 8: [DatabaseGenerated(DatabaseGeneratedOption.Computed)] 9: public string FullName { get; private set; } 10: } 11: 12: public class UserContext : DbContext 13: { 14: public DbSet<UserProfile> Users { get; set; } 15: } The DatabaseGenerated attribute is needed on our FullName property.  This is a hint to let Entity Framework Code First know that the database will be computing this property for us. Next, we need to run 2 commands in the Package Manager Console.  First, run Enable-Migrations to enable Code First Migrations for the UserContext.  Next, run Add-Migration Initial to create an initial migration.  This will create a migration that creates the UserProfile table with 3 columns: FirstName, LastName, and FullName.  This is where we need to make a small change.  Instead of allowing Code First Migrations to create the FullName property, we will manually add that column as a computed column. 1: public partial class Initial : DbMigration 2: { 3: public override void Up() 4: { 5: CreateTable( 6: "dbo.UserProfiles", 7: c => new 8: { 9: Id = c.Int(nullable: false, identity: true), 10: FirstName = c.String(), 11: LastName = c.String(), 12: //FullName = c.String(), 13: }) 14: .PrimaryKey(t => t.Id); 15: Sql("ALTER TABLE dbo.UserProfiles ADD FullName AS FirstName + ' ' + LastName"); 16: } 17: 18: 19: public override void Down() 20: { 21: DropTable("dbo.UserProfiles"); 22: } 23: } Finally, run the Update-Database command.  Now we can query for Users using the FullName property and that query will be executed on the database server.  However, we encounter another potential problem. Since the FullName property is calculated by the database, it will get out of sync on the object side as soon as we make a change to the FirstName or LastName property.  Luckily, we can have the best of both worlds here by also adding the calculation back to the getter on the FullName property: 1: [DatabaseGenerated(DatabaseGeneratedOption.Computed)] 2: public string FullName 3: { 4: get { return FirstName + " " + LastName; } 5: private set 6: { 7: //Just need this here to trick EF 8: } 9: } Now we can both query for Users using the FullName property and we also won’t need to worry about the FullName property being out of sync with the FirstName and LastName properties.  When we run this code: 1: using(UserContext context = new UserContext()) 2: { 3: UserProfile userProfile = new UserProfile {FirstName = "Chanandler", LastName = "Bong"}; 4: 5: Console.WriteLine("Before saving: " + userProfile.FullName); 6: 7: context.Users.Add(userProfile); 8: context.SaveChanges(); 9:  10: Console.WriteLine("After saving: " + userProfile.FullName); 11:  12: UserProfile chanandler = context.Users.First(u => u.FullName == "Chanandler Bong"); 13: Console.WriteLine("After reading: " + chanandler.FullName); 14:  15: chanandler.FirstName = "Chandler"; 16: chanandler.LastName = "Bing"; 17:  18: Console.WriteLine("After changing: " + chanandler.FullName); 19:  20: } We get this output: It took a bit of work, but finally Chandler’s TV Guide can be delivered to the right person. The obvious downside to this implementation is that the FullName calculation is duplicated in the database and in the UserProfile class. This sample was written using Visual Studio 2012 and Entity Framework 5. Download the source code here.

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  • To Bit or Not To Bit

    - by Johnm
    'Twas a long day of troubleshooting and firefighting and now, with most of the office vacant, you face a blank scripting window to create a new table in his database. Many questions circle your mind like dirty water gurgling down the bathtub drain: "How normalized should this table be?", "Should I use an identity column?", "NVarchar or Varchar?", "Should this column be NULLABLE?", "I wonder what apple blue cheese bacon cheesecake tastes like?" Well, there are times when the mind goes it's own direction. A Bit About Bit At some point during your table creation efforts you will encounter the decision of whether to use the bit data type for a column. The bit data type is an integer data type that recognizes only the values of 1, 0 and NULL as valid. This data type is often utilized to store yes/no or true/false values. An example of its use would be a column called [IsGasoline] which would be intended to contain the value of 1 if the row's subject (a car) had a gasoline engine and a 0 if the subject did not have a gasoline engine. The bit data type can even be found in some of the system tables of SQL Server. For example, the sysssispackages table in the msdb database which contains SQL Server Integration Services Package information for the packages stored in SQL Server. This table contains a column called [IsEncrypted]. A value of 1 indicates that the package has been encrypted while the value of 0 indicates that it is not. I have learned that the most effective way to disperse the crowd that surrounds the office coffee machine is to engage into SQL Server debates. The bit data type has been one of the most reoccurring, as well as the most enjoyable, of these topics. It contains a practical side and a philosophical side. Practical Consideration This data type certainly has its place and is a valuable option for database design; but it is often used in situations where the answer is really not a pure true/false response. In addition, true/false values are not very informative or scalable. Let's use the previously noted [IsGasoline] column for illustration. While on the surface it appears to be a rather simple question when evaluating a car: "Does the car have a gasoline engine?" If the person entering data is entering a row for a Jeep Liberty, the response would be a 1 since it has a gasoline engine. If the person is entering data is entering a row for a Chevrolet Volt, the response would be a 0 since it is an electric engine. What happens when a person is entering a row for the gasoline/electric hybrid Toyota Prius? Would one person's conclusion be consistent with another person's conclusion? The argument could be made that the current intent for the database is to be used only for pure gasoline and pure electric engines; but this is where the scalability issue comes into play. With the use of a bit data type a database modification and data conversion would be required if the business decided to take on hybrid engines. Whereas, alternatively, if the int data type were used as a foreign key to a reference table containing the engine type options, the change to include the hybrid option would only require an entry into the reference table. Philosophical Consideration Since the bit data type is often used for true/false or yes/no data (also called Boolean) it presents a philosophical conundrum of what to do about the allowance of the NULL value. The inclusion of NULL in a true/false or yes/no response simply violates the logical principle of bivalence which states that "every proposition is either true or false". If NULL is not true, then it must be false. The mathematical laws of Boolean logic support this concept by stating that the only valid values of this scenario are 1 and 0. There is another way to look at this conundrum: NULL is also considered to be the absence of a response. In other words, it is the equivalent to "undecided". Anyone who watches the news can tell you that polls always include an "undecided" option. This could be considered a valid option in the world of yes/no/dunno. Through out all of these considerations I have discovered one absolute certainty: When you have found a person, or group of persons, who are willing to entertain a philosophical debate of the bit data type, you have found some true friends.

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  • Null Values And The T-SQL IN Operator

    - by Jesse
    I came across some unexpected behavior while troubleshooting a failing test the other day that took me long enough to figure out that I thought it was worth sharing here. I finally traced the failing test back to a SELECT statement in a stored procedure that was using the IN t-sql operator to exclude a certain set of values. Here’s a very simple example table to illustrate the issue: Customers CustomerId INT, NOT NULL, Primary Key CustomerName nvarchar(100) NOT NULL SalesRegionId INT NULL   The ‘SalesRegionId’ column contains a number representing the sales region that the customer belongs to. This column is nullable because new customers get created all the time but assigning them to sales regions is a process that is handled by a regional manager on a periodic basis. For the purposes of this example, the Customers table currently has the following rows: CustomerId CustomerName SalesRegionId 1 Customer A 1 2 Customer B NULL 3 Customer C 4 4 Customer D 2 5 Customer E 3   How could we write a query against this table for all customers that are NOT in sales regions 2 or 4? You might try something like this: 1: SELECT 2: CustomerId, 3: CustomerName, 4: SalesRegionId 5: FROM Customers 6: WHERE SalesRegionId NOT IN (2,4)   Will this work? In short, no; at least not in the way that you might expect. Here’s what this query will return given the example data we’re working with: CustomerId CustomerName SalesRegionId 1 Customer A 1 5 Customer E 5   I was expecting that this query would also return ‘Customer B’, since that customer has a NULL SalesRegionId. In my mind, having a customer with no sales region should be included in a set of customers that are not in sales regions 2 or 4.When I first started troubleshooting my issue I made note of the fact that this query should probably be re-written without the NOT IN clause, but I didn’t suspect that the NOT IN clause was actually the source of the issue. This particular query was only one minor piece in a much larger process that was being exercised via an automated integration test and I simply made a poor assumption that the NOT IN would work the way that I thought it should. So why doesn’t this work the way that I thought it should? From the MSDN documentation on the t-sql IN operator: If the value of test_expression is equal to any value returned by subquery or is equal to any expression from the comma-separated list, the result value is TRUE; otherwise, the result value is FALSE. Using NOT IN negates the subquery value or expression. The key phrase out of that quote is, “… is equal to any expression from the comma-separated list…”. The NULL SalesRegionId isn’t included in the NOT IN because of how NULL values are handled in equality comparisons. From the MSDN documentation on ANSI_NULLS: The SQL-92 standard requires that an equals (=) or not equal to (<>) comparison against a null value evaluates to FALSE. When SET ANSI_NULLS is ON, a SELECT statement using WHERE column_name = NULL returns zero rows even if there are null values in column_name. A SELECT statement using WHERE column_name <> NULL returns zero rows even if there are nonnull values in column_name. In fact, the MSDN documentation on the IN operator includes the following blurb about using NULL values in IN sub-queries or expressions that are used with the IN operator: Any null values returned by subquery or expression that are compared to test_expression using IN or NOT IN return UNKNOWN. Using null values in together with IN or NOT IN can produce unexpected results. If I were to include a ‘SET ANSI_NULLS OFF’ command right above my SELECT statement I would get ‘Customer B’ returned in the results, but that’s definitely not the right way to deal with this. We could re-write the query to explicitly include the NULL value in the WHERE clause: 1: SELECT 2: CustomerId, 3: CustomerName, 4: SalesRegionId 5: FROM Customers 6: WHERE (SalesRegionId NOT IN (2,4) OR SalesRegionId IS NULL)   This query works and properly includes ‘Customer B’ in the results, but I ultimately opted to re-write the query using a LEFT OUTER JOIN against a table variable containing all of the values that I wanted to exclude because, in my case, there could potentially be several hundred values to be excluded. If we were to apply the same refactoring to our simple sales region example we’d end up with: 1: DECLARE @regionsToIgnore TABLE (IgnoredRegionId INT) 2: INSERT @regionsToIgnore values (2),(4) 3:  4: SELECT 5: c.CustomerId, 6: c.CustomerName, 7: c.SalesRegionId 8: FROM Customers c 9: LEFT OUTER JOIN @regionsToIgnore r ON r.IgnoredRegionId = c.SalesRegionId 10: WHERE r.IgnoredRegionId IS NULL By performing a LEFT OUTER JOIN from Customers to the @regionsToIgnore table variable we can simply exclude any rows where the IgnoredRegionId is null, as those represent customers that DO NOT appear in the ignored regions list. This approach will likely perform better if the number of sales regions to ignore gets very large and it also will correctly include any customers that do not yet have a sales region.

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  • Joining on NULLs

    - by Dave Ballantyne
    A problem I see on a fairly regular basis is that of dealing with NULL values.  Specifically here, where we are joining two tables on two columns, one of which is ‘optional’ ie is nullable.  So something like this: i.e. Lookup where all the columns are equal, even when NULL.   NULL’s are a tricky thing to initially wrap your mind around.  Statements like “NULL is not equal to NULL and neither is it not not equal to NULL, it’s NULL” can cause a serious brain freeze and leave you a gibbering wreck and needing your mummy. Before we plod on, time to setup some data to demo against. Create table #SourceTable ( Id integer not null, SubId integer null, AnotherCol char(255) not null ) go create unique clustered index idxSourceTable on #SourceTable(id,subID) go with cteNums as ( select top(1000) number from master..spt_values where type ='P' ) insert into #SourceTable select Num1.number,nullif(Num2.number,0),'SomeJunk' from cteNums num1 cross join cteNums num2 go Create table #LookupTable ( Id integer not null, SubID integer null ) go insert into #LookupTable Select top(100) id,subid from #SourceTable where subid is not null order by newid() go insert into #LookupTable Select top(3) id,subid from #SourceTable where subid is null order by newid() If that has run correctly, you will have 1 million rows in #SourceTable and 103 rows in #LookupTable.  We now want to join one to the other. First attempt – Lets just join select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and #LookupTable.SubID = #SourceTable.SubID OK, that’s a fail.  We had 100 rows back,  we didn’t correctly account for the 3 rows that have null values.  Remember NULL <> NULL and the join clause specifies SUBID=SUBID, which for those rows is not true. Second attempt – Lets deal with those pesky NULLS select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and isnull(#LookupTable.SubID,0) = isnull(#SourceTable.SubID,0) OK, that’s the right result, well done and 99.9% of the time that is where its left. It is a relatively trivial CPU overhead to wrap ISNULL around both columns and compare that result, so no problems.  But, although that’s true, this a relational database we are using here, not a procedural language.  SQL is a declarative language, we are making a request to the engine to get the results we want.  How we ask for them can make a ton of difference. Lets look at the plan for our second attempt, specifically the clustered index seek on the #SourceTable   There are 2 predicates. The ‘seek predicate’ and ‘predicate’.  The ‘seek predicate’ describes how SQLServer has been able to use an Index.  Here, it has been able to navigate the index to resolve where ID=ID.  So far so good, but what about the ‘predicate’ (aka residual probe) ? This is a row-by-row operation.  For each row found in the index matching the Seek Predicate, the leaf level nodes have been scanned and tested using this logical condition.  In this example [Expr1007] is the result of the IsNull operation on #LookupTable and that is tested for equality with the IsNull operation on #SourceTable.  This residual probe is quite a high overhead, if we can express our statement slightly differently to take full advantage of the index and make the test part of the ‘Seek Predicate’. Third attempt – X is null and Y is null So, lets state the query in a slightly manner: select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and ( #LookupTable.SubID = #SourceTable.SubID or (#LookupTable.SubID is null and #SourceTable.SubId is null) ) So its slightly wordier and may not be as clear in its intent to the human reader, that is what comments are for, but the key point is that it is now clearer to the query optimizer what our intention is. Let look at the plan for that query, again specifically the index seek operation on #SourceTable No ‘predicate’, just a ‘Seek Predicate’ against the index to resolve both ID and SubID.  A subtle difference that can be easily overlooked.  But has it made a difference to the performance ? Well, yes , a perhaps surprisingly high one. Clever query optimizer well done. If you are using a scalar function on a column, you a pretty much guaranteeing that a residual probe will be used.  By re-wording the query you may well be able to avoid this and use the index completely to resolve lookups. In-terms of performance and scalability your system will be in a much better position if you can.

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  • Local LINQtoSQL Database For Your Windows Phone 7 Application

    - by Tim Murphy
    There aren’t many applications that are of value without having some for of data store.  In Windows Phone development we have a few options.  You can store text directly to isolated storage.  You can also use a number of third party libraries to create or mimic databases in isolated storage.  With Mango we gained the ability to have a native .NET database approach which uses LINQ to SQL.  In this article I will try to bring together the components needed to implement this last type of data store and fill in some of the blanks that I think other articles have left out. Defining A Database The first things you are going to need to do is define classes that represent your tables and a data context class that is used as the overall database definition.  The table class consists of column definitions as you would expect.  They can have relationships and constraints as with any relational DBMS.  Below is an example of a table definition. First you will need to add some assembly references to the code file. using System.ComponentModel;using System.Data.Linq;using System.Data.Linq.Mapping; You can then add the table class and its associated columns.  It needs to implement INotifyPropertyChanged and INotifyPropertyChanging.  Each level of the class needs to be decorated with the attribute appropriate for that part of the definition.  Where the class represents the table the properties represent the columns.  In this example you will see that the column is marked as a primary key and not nullable with a an auto generated value. You will also notice that the in the column property’s set method It uses the NotifyPropertyChanging and NotifyPropertyChanged methods in order to make sure that the proper events are fired. [Table]public class MyTable: INotifyPropertyChanged, INotifyPropertyChanging{ public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if(PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } public event PropertyChangingEventHandler PropertyChanging; private void NotifyPropertyChanging(string propertyName) { if(PropertyChanging != null) { PropertyChanging(this, new PropertyChangingEventArgs(propertyName)); } } private int _TableKey; [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)] public int TableKey { get { return _TableKey; } set { NotifyPropertyChanging("TableKey"); _TableKey = value; NotifyPropertyChanged("TableKey"); } } The last part of the database definition that needs to be created is the data context.  This is a simple class that takes an isolated storage location connection string its constructor and then instantiates tables as public properties. public class MyDataContext: DataContext{ public MyDataContext(string connectionString): base(connectionString) { MyRecords = this.GetTable<MyTable>(); } public Table<MyTable> MyRecords;} Creating A New Database Instance Now that we have a database definition it is time to create an instance of the data context within our Windows Phone app.  When your app fires up it should check if the database already exists and create an instance if it does not.  I would suggest that this be part of the constructor of your ViewModel. db = new MyDataContext(connectionString);if(!db.DatabaseExists()){ db.CreateDatabase();} The next thing you have to know is how the connection string for isolated storage should be constructed.  The main sticking point I have found is that the database cannot be created unless the file mode is read/write.  You may have different connection strings but the initial one needs to be similar to the following. string connString = "Data Source = 'isostore:/MyApp.sdf'; File Mode = read write"; Using you database Now that you have done all the up front work it is time to put the database to use.  To make your life a little easier and keep proper separation between your view and your viewmodel you should add a couple of methods to the viewmodel.  These will do the CRUD work of your application.  What you will notice is that the SubmitChanges method is the secret sauce in all of the methods that change data. private myDataContext myDb;private ObservableCollection<MyTable> _viewRecords;public ObservableCollection<MyTable> ViewRecords{ get { return _viewRecords; } set { _viewRecords = value; NotifyPropertyChanged("ViewRecords"); }}public void LoadMedstarDbData(){ var tempItems = from MyTable myRecord in myDb.LocalScans select myRecord; ViewRecords = new ObservableCollection<MyTable>(tempItems);}public void SaveChangesToDb(){ myDb.SubmitChanges();}public void AddMyTableItem(MyTable newScan){ myDb.LocalScans.InsertOnSubmit(newScan); myDb.SubmitChanges();}public void DeleteMyTableItem(MyTable newScan){ myDb.LocalScans.DeleteOnSubmit(newScan); myDb.SubmitChanges();} Updating existing database What happens when you need to change the structure of your database?  Unfortunately you have to add code to your application that checks the version of the database which over time will create some pollution in your codes base.  On the other hand it does give you control of the update.  In this example you will see the DatabaseSchemaUpdater in action.  Assuming we added a “Notes” field to the MyTable structure, the following code will check if the database is the latest version and add the field if it isn’t. if(!myDb.DatabaseExists()){ myDb.CreateDatabase();}else{ DatabaseSchemaUpdater dbUdater = myDb.CreateDatabaseSchemaUpdater(); if(dbUdater.DatabaseSchemaVersion < 2) { dbUdater.AddColumn<MyTable>("Notes"); dbUdater.DatabaseSchemaVersion = 2; dbUdater.Execute(); }} Summary This approach does take a fairly large amount of work, but I think the end product is robust and very native for .NET developers.  It turns out to be worth the investment. del.icio.us Tags: Windows Phone,Windows Phone 7,LINQ to SQL,LINQ,Database,Isolated Storage

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  • ASP.NET: Including JavaScript libraries conditionally from CDN

    - by DigiMortal
    When developing cloud applications it is still useful to build them so they can run also on local machine without network connection. One thing you use from CDN when in cloud and from app folder when not connected are common JavaScript libraries. In this posting I will show you how to add support for local and CDN script stores to your ASP.NET MVC web application. Our solution is simple. We will add new configuration setting to our web.config file (including cloud transform file of it) and new property to our web application. In master page where scripts are included we will include scripts from CDN conditionally. There is nothing complex, all changes we make are simple ones. 1. Adding new property to web application Although I am using ASP.NET MVC web application these modifications work also very well with ASP.NET Forms. Open Global.asax and add new static property to your application class. public static bool UseCdn {     get     {         var valueString = ConfigurationManager.AppSettings["useCdn"];         bool useCdn;           bool.TryParse(valueString, out useCdn);         return useCdn;     } } If you want less round-trips to configuration data you can keep some nullable boolean in your application class scope and load CDN setting first time it is asked. 2. Adding new configuration setting to web.config By default my application uses local scripts. Although my application runs on cloud I can do a lot of stuff without staging environment in cloud. So by default I don’t have costs on traffic when including scripts from application folders. <appSettings>   <add key="UseCdn" value="false" /> </appSettings> You can also set UseCdn value to true and change it to false when you are not connected to network. 3. Modifying web.config cloud transform I have special configuration for my solution that I use when deploying my web application to cloud. This configuration is called Cloud and transform for this configuration is located in web.cloud.config. To make application using CDN when deployed to cloud we need the following transform. <appSettings>   <add key="UseCdn"        value="true"        xdt:Transform="SetAttributes"        xdt:Locator="Match(key)" /> </appSettings> Now when you publish your application to cloud it uses CDN by default. 4. Including scripts in master pages The last thing we need to change is our master page. My solution is simple. I check if I have to include scripts from CDN and if it is true then I include scripts from there. Otherwise my scripts will be included from application folder. @if (MyWeb.MvcApplication.UseCdn) {     <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.4.min.js" type="text/javascript"></script> } else {     <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> } Although here is only one script shown you can add all your scripts that are also available in some CDN in this if-else block. You are free to include scripts from different CDN services if you need. Conclusion As we saw it was very easy to modify our application to make it use CDN for JavaScript libraries in cloud and local scripts when run on local machine. We made only small changes to our application code, configuration and master pages to get different script sources supported. Our application is now more independent from external sources when we are working on it.

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  • Entity Framework SaveChanges error details

    - by Marek Karbarz
    When saving changes with SaveChanges on a data context is there a way to determine which Entity causes an error? For example, sometimes I'll forget to assign a date to a non-nullable date field and get "Invalid Date Range" error, but I get no information about which entity or which field it's caused by (I can usually track it down by painstakingly going through all my objects, but it's very time consuming). Stack trace is pretty useless as it only shows me an error at the SaveChanges call without any additional information as to where exactly it happened. Note that I'm not looking to solve any particular problem I have now, I would just like to know in general if there's a way to tell which entity/field is causing a problem. Quick sample of a stack trace as an example - in this case an error happened because CreatedOn date was not set on IAComment entity, however it's impossible to tell from this error/stack trace [SqlTypeException: SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.] System.Data.SqlTypes.SqlDateTime.FromTimeSpan(TimeSpan value) +2127345 System.Data.SqlTypes.SqlDateTime.FromDateTime(DateTime value) +232 System.Data.SqlClient.MetaType.FromDateTime(DateTime dateTime, Byte cb) +46 System.Data.SqlClient.TdsParser.WriteValue(Object value, MetaType type, Byte scale, Int32 actualLength, Int32 encodingByteSize, Int32 offset, TdsParserStateObject stateObj) +4997789 System.Data.SqlClient.TdsParser.TdsExecuteRPC(_SqlRPC[] rpcArray, Int32 timeout, Boolean inSchema, SqlNotificationRequest notificationRequest, TdsParserStateObject stateObj, Boolean isCommandProc) +6248 System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) +987 System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +162 System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +32 System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) +141 System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior) +12 System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior) +10 System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues) +8084396 System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) +267 [UpdateException: An error occurred while updating the entries. See the inner exception for details.] System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) +389 System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache) +163 System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options) +609 IADAL.IAController.Save(IAHeader head) in C:\Projects\IA\IADAL\IAController.cs:61 IA.IAForm.saveForm(Boolean validate) in C:\Projects\IA\IA\IAForm.aspx.cs:198 IA.IAForm.advance_Click(Object sender, EventArgs e) in C:\Projects\IA\IA\IAForm.aspx.cs:287 System.Web.UI.WebControls.Button.OnClick(EventArgs e) +118 System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +112 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5019

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  • Html.EditorFor not updating model on post

    - by Dave
    I have a complex type composed of two nullable DateTimes: public class Period { public DateTime? Start { get; set; } public DateTime? End { get; set; } public static implicit operator string(Period period) { /* converts from Period to string */ } public static implicit operator Period(string value) { /* and back again */ } } I want to display them together in a single textbox as a date range so I can provide a nice jQuery UI date range selector. To make that happen have the following custom editor template: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<Period>" %> <% string name = ViewData.TemplateInfo.HtmlFieldPrefix; %> <%= Html.PeriodTextBox(name, Model.EarliestDate, Model.LatestDate) %> Where Html.PeriodTextBox is an extension method I've written that just concatenates the two dates sensibly, turns off autocomplete and generates a textbox, like so: public static MvcHelperString PeriodTextBox(this HtmlHelper helper, string name, DateTime? startDate, DateTime? endDate) { TagBuilder builder = new TagBuilder("input"); builder.GenerateId(name); builder.Attributes.Add("name", name); builder.Attributes.Add("type", "text"); builder.Attributes.Add("autocomplete", "off"); builder.Attributes.Add("value", ConcatDates(startDate, endDate)); return MvcHtmlString.Create(builder.ToString()); } That's working fine in that I can call <%= Html.EditorFor(m => m.ReportPeriod) %> and I get my textbox, then when the form is submitted the FormCollection passed to the post action will contain an entry named ReportPeriod with the correct value. [HttpPost] public ActionResult ReportByRange(FormCollection formValues) { Period reportPeriod = formValues["ReportPeriod"]; // creates a Period, with the expected values } The problem is if I replace the FormCollection with the model type I'm passing to the view then the ReportPeriod property never gets set. [HttpPost] public ActionResult ReportByRange(ReportViewModel viewModel) { Period reportPeriod = viewModel.ReportPeriod; // this is null } I expected MVC would try to set the string from the textbox to that property and it would automatically generate a Period (as in my FormCollection example), but it's not. How do I tell the textbox I've generated in the custom editor to poplate that property on the model?

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  • Using MVC2 to update an Entity Framework v4 object with foreign keys fails

    - by jbjon
    With the following simple relational database structure: An Order has one or more OrderItems, and each OrderItem has one OrderItemStatus. Entity Framework v4 is used to communicate with the database and entities have been generated from this schema. The Entities connection happens to be called EnumTestEntities in the example. The trimmed down version of the Order Repository class looks like this: public class OrderRepository { private EnumTestEntities entities = new EnumTestEntities(); // Query Methods public Order Get(int id) { return entities.Orders.SingleOrDefault(d => d.OrderID == id); } // Persistence public void Save() { entities.SaveChanges(); } } An MVC2 app uses Entity Framework models to drive the views. I'm using the EditorFor feature of MVC2 to drive the Edit view. When it comes to POSTing back any changes to the model, the following code is called: [HttpPost] public ActionResult Edit(int id, FormCollection formValues) { // Get the current Order out of the database by ID Order order = orderRepository.Get(id); var orderItems = order.OrderItems; try { // Update the Order from the values posted from the View UpdateModel(order, ""); // Without the ValueProvider suffix it does not attempt to update the order items UpdateModel(order.OrderItems, "OrderItems.OrderItems"); // All the Save() does is call SaveChanges() on the database context orderRepository.Save(); return RedirectToAction("Details", new { id = order.OrderID }); } catch (Exception e) { return View(order); // Inserted while debugging } } The second call to UpdateModel has a ValueProvider suffix which matches the auto-generated HTML input name prefixes that MVC2 has generated for the foreign key collection of OrderItems within the View. The call to SaveChanges() on the database context after updating the OrderItems collection of an Order using UpdateModel generates the following exception: "The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted." When debugging through this code, I can still see that the EntityKeys are not null and seem to be the same value as they should be. This still happens when you are not changing any of the extracted Order details from the database. Also the entity connection to the database doesn't change between the act of Getting and the SaveChanges so it doesn't appear to be a Context issue either. Any ideas what might be causing this problem? I know EF4 has done work on foreign key properties but can anyone shed any light on how to use EF4 and MVC2 to make things easy to update; rather than having to populate each property manually. I had hoped the simplicity of EditorFor and DisplayFor would also extend to Controllers updating data. Thanks

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  • Nhibernate: One-To-Many mapping problem - Cannot cascade delete without inverse. Set NULL error

    - by KnaveT
    Hi, I have the current scenario whereby an Article has only 1 Outcome each. Each Article may or may not have an Outcome. In theory, this is a one-to-one mapping, but since NHibernate does not really support one-to-one, I used a One-To-Many to substitute. My Primary Key on the child table is actually the ArticleID (FK). So I have the following setup: Classes public class Article { public virtual Int32 ID { get;set;} private ICollection<ArticleOutcome> _Outcomes {get;set;} public virtual ArticleOutcome Outcome { get { if( this._Outcomes !=null && this._Outcomes.Count > 0 ) return this._Outcomes.First(); return null; } set { if( value == null ) { if( this._Outcomes !=null && this._Outcomes.Count > 0 ) this._Outcomes.Clear(); } else { if( this._Outcomes == null ) this._Outcomes = new HashSet<ArticleOutcome>(); else if ( this._Outcomes.Count >= 1 ) this._Outcomes.Clear(); this._Outcomes.Add( value ); } } } } public class ArticleOutcome { public virtual Int32 ID { get;set; } public virtual Article ParentArticle { get;set;} } Mappings public class ArticleMap : ClassMap<Article> { public ArticleMap() { this.Id( x=> x.ID ).GeneratedBy.Identity(); this.HasMany<ArticleOutcome>( Reveal.Property<Article>("_Outcomes") ) .AsSet().KeyColumn("ArticleID") .Cascade.AllDeleteOrphan() //Cascade.All() doesn't work too. .LazyLoad() .Fetch.Select(); } } public class ArticleOutcomeMap : ClassMap<ArticleOutcome> { public ArticleOutcomeMap(){ this.Id( x=> x.ID, "ArticleID").GeneratedBy.Foreign("ParentArticle"); this.HasOne( x=> x.ParentArticle ).Constrained (); //This do not work also. //this.References( x=> x.ParentArticle, "ArticleID" ).Not.Nullable(); } } Now my problem is this: It works when I do an insert/update of the Outcome. e.g. var article = new Article(); article.Outcome = new ArticleOutcome { xxx = "something" }; session.Save( article ); However, I encounter SQL errors when attempting to delete via the Article itself. var article = session.Get( 123 ); session.Delete( article ); //throws SQL error. The error is something to the like of Cannot insert NULL into ArticleID in ArticleOutcome table. The deletion works if I place Inverse() to the Article's HasMany() mapping, but insertion will fail. Does anyone have a solution for this? Or do I really have to add a surrogate key to the ArticleOutcome table?

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  • JPA @OneToMany and composite PK

    - by Fleuri F
    Good Morning, I am working on project using JPA. I need to use a @OneToMany mapping on a class that has three primary keys. You can find the errors and the classes after this. If anyone has an idea! Thanks in advance! FF javax.persistence.PersistenceException: No Persistence provider for EntityManager named JTA_pacePersistence: Provider named oracle.toplink.essentials.PersistenceProvider threw unexpected exception at create EntityManagerFactory: javax.persistence.PersistenceException javax.persistence.PersistenceException: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupException Exception Description: predeploy for PersistenceUnit [JTA_pacePersistence] failed. Internal Exception: Exception [TOPLINK-7220] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ValidationException Exception Description: The @JoinColumns on the annotated element [private java.util.Set isd.pacepersistence.common.Action.permissions] from the entity class [class isd.pacepersistence.common.Action] is incomplete. When the source entity class uses a composite primary key, a @JoinColumn must be specified for each join column using the @JoinColumns. Both the name and the referenceColumnName elements must be specified in each such @JoinColumn. at oracle.toplink.essentials.internal.ejb.cmp3.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:643) at oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider.createEntityManagerFactory(EntityManagerFactoryProvider.java:196) at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:110) at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83) at isd.pacepersistence.common.DataMapper.(Unknown Source) at isd.pacepersistence.server.MainServlet.getDebugCase(Unknown Source) at isd.pacepersistence.server.MainServlet.doGet(Unknown Source) at javax.servlet.http.HttpServlet.service(HttpServlet.java:718) at javax.servlet.http.HttpServlet.service(HttpServlet.java:831) at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:411) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:290) at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:271) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:202) There is the source code of my classes : Action : @Entity @Table(name="action") public class Action { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int num; @ManyToOne(cascade= { CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH }) @JoinColumn(name="domain_num") private Domain domain; private String name; private String description; @OneToMany @JoinTable(name="permission", joinColumns= { @JoinColumn(name="action_num", referencedColumnName="action_num", nullable=false, updatable=false) }, inverseJoinColumns= { @JoinColumn(name="num") }) private Set<Permission> permissions; public Action() { } Permission : @SuppressWarnings("serial") @Entity @Table(name="permission") public class Permission implements Serializable { @EmbeddedId private PermissionPK primaryKey; @ManyToOne @JoinColumn(name="action_num", insertable=false, updatable=false) private Action action; @ManyToOne @JoinColumn(name="entity_num", insertable=false, updatable=false) private isd.pacepersistence.common.Entity entity; @ManyToOne @JoinColumn(name="class_num", insertable=false, updatable=false) private Clazz clazz; private String kondition; public Permission() { } PermissionPK : @SuppressWarnings("serial") @Entity @Table(name="permission") public class Permission implements Serializable { @EmbeddedId private PermissionPK primaryKey; @ManyToOne @JoinColumn(name="action_num", insertable=false, updatable=false) private Action action; @ManyToOne @JoinColumn(name="entity_num", insertable=false, updatable=false) private isd.pacepersistence.common.Entity entity; @ManyToOne @JoinColumn(name="class_num", insertable=false, updatable=false) private Clazz clazz; private String kondition; public Permission() { }

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  • JPA @ManyToOne and composite PK

    - by Fleuri F
    Good Morning, I am working on project using JPA. I need to use a @ManyToOne mapping on a class that has three primary keys. You can find the errors and the classes after this. If anyone has an idea! Thanks in advance! FF javax.persistence.PersistenceException: No Persistence provider for EntityManager named JTA_pacePersistence: Provider named oracle.toplink.essentials.PersistenceProvider threw unexpected exception at create EntityManagerFactory: javax.persistence.PersistenceException javax.persistence.PersistenceException: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupException Exception Description: predeploy for PersistenceUnit [JTA_pacePersistence] failed. Internal Exception: Exception [TOPLINK-7220] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ValidationException Exception Description: The @JoinColumns on the annotated element [private java.util.Set isd.pacepersistence.common.Action.permissions] from the entity class [class isd.pacepersistence.common.Action] is incomplete. When the source entity class uses a composite primary key, a @JoinColumn must be specified for each join column using the @JoinColumns. Both the name and the referenceColumnName elements must be specified in each such @JoinColumn. at oracle.toplink.essentials.internal.ejb.cmp3.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:643) at oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider.createEntityManagerFactory(EntityManagerFactoryProvider.java:196) at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:110) at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83) at isd.pacepersistence.common.DataMapper.(Unknown Source) at isd.pacepersistence.server.MainServlet.getDebugCase(Unknown Source) at isd.pacepersistence.server.MainServlet.doGet(Unknown Source) at javax.servlet.http.HttpServlet.service(HttpServlet.java:718) at javax.servlet.http.HttpServlet.service(HttpServlet.java:831) at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:411) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:290) at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:271) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:202) There is the source code of my classes : Action : @Entity @Table(name="action") public class Action { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int num; @ManyToOne(cascade= { CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH }) @JoinColumn(name="domain_num") private Domain domain; private String name; private String description; @OneToMany @JoinTable(name="permission", joinColumns= { @JoinColumn(name="action_num", referencedColumnName="action_num", nullable=false, updatable=false) }, inverseJoinColumns= { @JoinColumn(name="num") }) private Set<Permission> permissions; public Action() { } Permission : @SuppressWarnings("serial") @Entity @Table(name="permission") public class Permission implements Serializable { @EmbeddedId private PermissionPK primaryKey; @ManyToOne @JoinColumn(name="action_num", insertable=false, updatable=false) private Action action; @ManyToOne @JoinColumn(name="entity_num", insertable=false, updatable=false) private isd.pacepersistence.common.Entity entity; @ManyToOne @JoinColumn(name="class_num", insertable=false, updatable=false) private Clazz clazz; private String kondition; public Permission() { } PermissionPK : @SuppressWarnings("serial") @Entity @Table(name="permission") public class Permission implements Serializable { @EmbeddedId private PermissionPK primaryKey; @ManyToOne @JoinColumn(name="action_num", insertable=false, updatable=false) private Action action; @ManyToOne @JoinColumn(name="entity_num", insertable=false, updatable=false) private isd.pacepersistence.common.Entity entity; @ManyToOne @JoinColumn(name="class_num", insertable=false, updatable=false) private Clazz clazz; private String kondition; public Permission() { }

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  • Fluent | Nhibernate multiple inheritance mapping?

    - by Broken Pipe
    I'm trying to map this classes: public interface IBusinessObject { Guid Id { get; set; } } public class Product { public virtual Guid Id { get; set; } public virtual int ProductTypeId { get; set; } } public class ProductWeSell : Product, IBusinessObject { } public class ProductWeDontSell : Product { } Using this Fluent mapping code: public class IBusinessObjectMap : ClassMap<IBusinessObject> { public IBusinessObjectMap() { Id(t => t.Id).GeneratedBy.Guid(); Table("BusinessObject"); } } public class ProductMap : ClassMap<Product> { public ProductMap() { Id(t => t.Id); DiscriminateSubClassesOnColumn("ProductTypeId", "null").Nullable(); } } public class ProductWeSellMap : SubclassMap<ProductWeSell> { public ProductWeSellMap() { DiscriminatorValue(1); KeyColumn("Id"); } } public class ProductWeDontSellMap : SubclassMap<ProductWeDontSell> { public ProductWeDontSellMap() { DiscriminatorValue(2); KeyColumn("Id"); } } But I get {"Duplicate class/entity mapping ProductWeSell"} error. And if we take a look at generated HBM, indeed it's duplicated, but i have no idea how to write this mapping without duplicating it if it's possible at all. Produced hbm: <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <class xmlns="urn:nhibernate-mapping-2.2" name="IBusinessObject" table="BusinessObject"> <joined-subclass name="ProductWeSell" table="ProductWeSell"/> </class> </hibernate-mapping> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <class xmlns="urn:nhibernate-mapping-2.2" discriminator-value="null" name="Product" table="Product"> <discriminator type="String"> <column name="ProductTypeId" not-null="false" /> </discriminator> <subclass name="ProductWeDontSell" discriminator-value="2" /> <subclass name="ProductWeSell" discriminator-value="1" /> </class> </hibernate-mapping> So far I was unable to figure out how to map this using fluent Nhibernate (i haven't tried mapping this using hmb files). Any help appreciated Fluent or HBM files. The thing I'm trying to solve look identical to this topic: NHibernate inheritance mapping question

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  • nhibernate/fluenthibernate throws StackOverflowException

    - by Gianluca Colucci
    Hi there! In my project I am using NHibernate/FluentNHibernate, and I am working with two entities, contracts and services. This is my contract type: [Serializable] public partial class TTLCContract { public virtual long? Id { get; set; } // other properties here public virtual Iesi.Collections.Generic.ISet<TTLCService> Services { get; set; } // implementation of Equals // and GetHashCode here } and this is my service type: [Serializable] public partial class TTLCService { public virtual long? Id { get; set; } // other properties here public virtual Activity.Models.TTLCContract Contract { get; set; } // implementation of Equals // and GetHashCode here } Ok, so as you can see, I want my contract object to have many services, and each Service needs to have a reference to the parent Contract. I am using FluentNhibernate. So my mappings file are the following: public TTLCContractMapping() { Table("tab_tlc_contracts"); Id(x => x.Id, "tlc_contract_id"); HasMany(x => x.Services) .Inverse() .Cascade.All() .KeyColumn("tlc_contract_id") .AsSet(); } and public TTLCServiceMapping() { Table("tab_tlc_services"); Id(x => x.Id, "tlc_service_id"); References(x => x.Contract) .Not.Nullable() .Column("tlc_contract_id"); } and here comes my problem: if I retrieve the list of all contracts in the db, it works. if I retrieve the list of all services in a given contract, I get a StackOverflowException.... Do you see anything wrong with what I wrote? Have I made any mistake? Please let me know if you need any additional information. Oh yes, I missed to say... looking at the stacktrace I see the system is loading all the services and then it is loading again the contracts related to those services. I don't really have the necessary experience nor ideas anymore to understand what's going on.. so any help would be really really great! Thanks in advance, Cheers, Gianluca.

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  • Cannot instantiate abstract class or interface : problem while persisting

    - by sammy
    i have a class campaign that maintains a list of AdGroupInterfaces. im going to persist its implementation @Entity @Table(name = "campaigns") public class Campaign implements Serializable,Comparable<Object>,CampaignInterface { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @OneToMany ( cascade = {CascadeType.ALL}, fetch = FetchType.EAGER, targetEntity=AdGroupInterface.class ) @org.hibernate.annotations.Cascade( value = org.hibernate.annotations.CascadeType.DELETE_ORPHAN ) @org.hibernate.annotations.IndexColumn(name = "CHOICE_POSITION") private List<AdGroupInterface> AdGroup; public Campaign() { super(); } public List<AdGroupInterface> getAdGroup() { return AdGroup; } public void setAdGroup(List<AdGroupInterface> adGroup) { AdGroup = adGroup; } public void set1AdGroup(AdGroupInterface adGroup) { if(AdGroup==null) AdGroup=new LinkedList<AdGroupInterface>(); AdGroup.add(adGroup); } } AdGroupInterface's implementation is AdGroups. when i add an adgroup to the list in campaign, campaign c; c.getAdGroupList().add(new AdGroups()), etc and save campaign it says"Cannot instantiate abstract class or interface :" AdGroupInterface its not recognizing the implementation just before persisting... Whereas Persisting adGroups separately works. when it is a member of another entity, it doesnt get persisted. import java.io.Serializable; import java.util.List; import javax.persistence.*; @Entity @DiscriminatorValue("1") @Table(name = "AdGroups") public class AdGroups implements Serializable,Comparable,AdGroupInterface{ /** * */ private static final long serialVersionUID = 1L; private Long Id; private String Name; private CampaignInterface Campaign; private MonetaryValue DefaultBid; public AdGroups(){ super(); } public AdGroups( String name, CampaignInterface campaign) { super(); this.Campaign=new Campaign(); Name = name; this.Campaign = campaign; DefaultBid = defaultBid; AdList=adList; } @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="AdGroup_Id") public Long getId() { return Id; } public void setId(Long id) { Id = id; } @Column(name="AdGroup_Name") public String getName() { return Name; } public void setName(String name) { Name = name; } @ManyToOne @JoinColumn (name="Cam_ID", nullable = true,insertable = false) public CampaignInterface getCampaign() { return Campaign; } public void setCampaign(CampaignInterface campaign) { this.Campaign = campaign; } } what am i missing?? please look into it ...

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  • What is the best way to archive data in a relational database?

    - by GenericTypeTea
    I have a bit of an issue with a particular aspect of a program I'm working on. I need the ability to archive (fix) a table so that a change anywhere in the system will not affect the results it returns. This is the basic structure of what I need to fix: Recipe --> Recipe (as sub recipe) Recipe --> Ingredients So, if I fix a Recipe, I need to ensure all the sub recipes (including all the sub recipes sub recipes and so forth) are fixed and all its ingredients are fixed. The problem is that the sub recipe and ingredients still need to be modifiable as they are used by other recipes that are not fixed. I came up with a solution whereby I serialize (with protobuf-net) a master object that deals with the recipe and all the sub recipes and ingredients and save the archive data to a table like follows: Archive{ ReferenceId, (i.e. RecipeId) ReferenceTypeId, (i.e. Recipe) ArchiveData varbinary(max) } Now, this works great and is almost perfect... however I totally forgot (I'd love to blame the agile development mentally, however this was just short sighted) that this information needs to be reported on. As far as I'm aware I can't think how I could inflate the serialized data back into my Recipe Object and use it in a Report. I'm using the standard SQL 2005 report services at the moment. Alternatively, I guess I could do the following: Duplicate every table and tag the word "Archive" on the end of the table name. This would then give me an area of specific archive data... but ignoring my simplified example, there'd actually be about 15 tables duplicated. Add a nullable, non-foreign key property called "CopiedFromId" to every table that contains fixed data and duplicate every record that the recipe (and all it's sub recipes and all their sub recipes) touches. Create some sort of denormalised structure that could be restored from at a later date to the original, unfixed recipe. Although I think this would be like option 1 and involve a lot of extra tables. Anyway, I'm at a total loss and do not like any of the ideas particularly. Can anyone please advise the best course of action? EDIT: Or 4) Create tables specific to what the report requires and populate them with the data when the user clicks the report button? This would cause about 4 extra tables for the report in question.

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