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  • How to implement EntityDataSource Where IN entity sql clause

    - by TonyS
    I want to pass a number of values into a parameter of the EntityDataSource, e.g.: Where="it.ORDER_ID IN {@OrderIdList}" (this is a property on the EntityDataSource) <WhereParameters> <asp:ControlParameter Name="OrderIdList" Type="Int16" ControlID="OrderFilterControl" PropertyName="OrderIdList" /> </WhereParameters> This doesn't work as ORDER_ID is of type int32 and I need to pass in multiple values, e.g. {1,2,3} etc The next thing I tried was setting the Where clause in code-behind and this all works except I can't get data binding on DropDownLists to work. By this I mean no value is returned from the bound dropdownlists in the EntityDataSource Updating Event. My ideal solution would be to use a WhereParameter on the EntityDataSource but any help is appreciated. Thanks, Tony. A complete code example follows using the AdventureWorks db: Public Class EntityDataSourceWhereInClause Inherits System.Web.UI.Page Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load CustomersEntityDataSource.Where = WhereClause ''# reset after each postback as its lost otherwise End Sub Private Sub cmdFilterCustomers_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmdFilterCustomers.Click Dim CustomerIdList As New Generic.List(Of Int32) For Each item As ListItem In CustomerIdCheckBoxList.Items If item.Selected Then CustomerIdList.Add(item.Value) End If Next Dim CustomerCsvList As String = String.Join(", ", CustomerIdList.Select(Function(o) o.ToString()).ToArray()) WhereClause = "it.CustomerID IN {" & CustomerCsvList & "}" CustomersEntityDataSource.Where = WhereClause FormView1.PageIndex = 0 End Sub ''# save between postbacks the custom Where IN clause Public Property WhereClause() As String Get Return ViewState("WhereClause") End Get Set(ByVal value As String) ViewState.Add("WhereClause", value) End Set End Property Private Sub CustomersEntityDataSource_Updating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.EntityDataSourceChangingEventArgs) Handles CustomersEntityDataSource.Updating Dim c = CType(e.Entity, EntityFrameworkTest.Customer) If c.Title.Length = 0 Then Response.Write("Title is empty string, so will save like this!") End If End Sub End Class <%@ Page Language="vb" AutoEventWireup="false" CodeBehind="EntityDataSourceWhereInClause.aspx.vb" Inherits="EntityFrameworkTest.EntityDataSourceWhereInClause" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <%''# filter control %> <div> <asp:EntityDataSource ID="CustomerIdListEntityDataSource" runat="server" ConnectionString="name=AdventureWorksLT2008Entities" DefaultContainerName="AdventureWorksLT2008Entities" EnableFlattening="False" EntitySetName="Customers" Select="it.[CustomerID]" OrderBy="it.[CustomerID]"> </asp:EntityDataSource> <asp:CheckBoxList ID="CustomerIdCheckBoxList" runat="server" DataSourceID="CustomerIdListEntityDataSource" DataTextField="CustomerID" DataValueField="CustomerID" RepeatDirection="Horizontal"> </asp:CheckBoxList> <asp:Button ID="cmdFilterCustomers" runat="server" Text="Apply Filter" /> </div> <% ''# you get this error passing in CSV in the where clause ''# The element type 'Edm.Int32' and the CollectionType 'Transient.collection[Edm.String(Nullable=True,DefaultValue=,MaxLength=,Unicode=,FixedLength=)]' are not compatible. The IN expression only supports entity, primitive, and reference types. Near WHERE predicate, line 6, column 15. ''# so have coded it manually in code-behind Where="it.CustomerID IN {@OrderIdList}" %> <asp:EntityDataSource ID="CustomersEntityDataSource" runat="server" ConnectionString="name=AdventureWorksLT2008Entities" DefaultContainerName="AdventureWorksLT2008Entities" EnableFlattening="False" EnableUpdate="True" EntitySetName="Customers" AutoGenerateOrderByClause="false"> </asp:EntityDataSource> <%''# updating works with DropDownLists until the Where clause is set in code %> <asp:FormView ID="FormView1" runat="server" AllowPaging="True" CellPadding="4" DataKeyNames="CustomerID" DataSourceID="CustomersEntityDataSource" ForeColor="#333333"> <EditItemTemplate> CustomerID: <asp:Label ID="CustomerIDLabel1" runat="server" Text='<%# Eval("CustomerID") %>' /> <br /> NameStyle: <asp:CheckBox ID="NameStyleCheckBox" runat="server" Checked='<%# Bind("NameStyle") %>' /> <br /> Title: <%''# the SelectedValue is not Bound to the EF object if the Where clause is updated in code-behind %> <asp:DropDownList ID="ddlTitleBound" runat="server" DataSourceID="TitleEntityDataSource" DataTextField="Title" DataValueField="Title" AutoPostBack="false" AppendDataBoundItems="true" SelectedValue='<%# Bind("Title") %>'> </asp:DropDownList> <asp:EntityDataSource ID="TitleEntityDataSource" runat="server" ConnectionString="name=AdventureWorksLT2008Entities" DefaultContainerName="AdventureWorksLT2008Entities" EnableFlattening="False" EntitySetName="Customers" Select="it.[Title]" GroupBy="it.[Title]" ViewStateMode="Enabled"> </asp:EntityDataSource> <br /> FirstName: <asp:TextBox ID="FirstNameTextBox" runat="server" Text='<%# Bind("FirstName") %>' /> <br /> MiddleName: <asp:TextBox ID="MiddleNameTextBox" runat="server" Text='<%# Bind("MiddleName") %>' /> <br /> LastName: <asp:TextBox ID="LastNameTextBox" runat="server" Text='<%# Bind("LastName") %>' /> <br /> Suffix: <asp:TextBox ID="SuffixTextBox" runat="server" Text='<%# Bind("Suffix") %>' /> <br /> CompanyName: <asp:TextBox ID="CompanyNameTextBox" runat="server" Text='<%# Bind("CompanyName") %>' /> <br /> SalesPerson: <asp:TextBox ID="SalesPersonTextBox" runat="server" Text='<%# Bind("SalesPerson") %>' /> <br /> EmailAddress: <asp:TextBox ID="EmailAddressTextBox" runat="server" Text='<%# Bind("EmailAddress") %>' /> <br /> Phone: <asp:TextBox ID="PhoneTextBox" runat="server" Text='<%# Bind("Phone") %>' /> <br /> PasswordHash: <asp:TextBox ID="PasswordHashTextBox" runat="server" Text='<%# Bind("PasswordHash") %>' /> <br /> PasswordSalt: <asp:TextBox ID="PasswordSaltTextBox" runat="server" Text='<%# Bind("PasswordSalt") %>' /> <br /> rowguid: <asp:TextBox ID="rowguidTextBox" runat="server" Text='<%# Bind("rowguid") %>' /> <br /> ModifiedDate: <asp:TextBox ID="ModifiedDateTextBox" runat="server" Text='<%# Bind("ModifiedDate") %>' /> <br /> <asp:LinkButton ID="UpdateButton" runat="server" CausesValidation="True" CommandName="Update" Text="Update" /> &nbsp;<asp:LinkButton ID="UpdateCancelButton" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel" /> </EditItemTemplate> <EditRowStyle BackColor="#999999" /> <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <ItemTemplate> CustomerID: <asp:Label ID="CustomerIDLabel" runat="server" Text='<%# Eval("CustomerID") %>' /> <br /> NameStyle: <asp:CheckBox ID="NameStyleCheckBox" runat="server" Checked='<%# Bind("NameStyle") %>' Enabled="false" /> <br /> Title: <asp:Label ID="TitleLabel" runat="server" Text='<%# Bind("Title") %>' /> <br /> FirstName: <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Bind("FirstName") %>' /> <br /> MiddleName: <asp:Label ID="MiddleNameLabel" runat="server" Text='<%# Bind("MiddleName") %>' /> <br /> LastName: <asp:Label ID="LastNameLabel" runat="server" Text='<%# Bind("LastName") %>' /> <br /> Suffix: <asp:Label ID="SuffixLabel" runat="server" Text='<%# Bind("Suffix") %>' /> <br /> CompanyName: <asp:Label ID="CompanyNameLabel" runat="server" Text='<%# Bind("CompanyName") %>' /> <br /> SalesPerson: <asp:Label ID="SalesPersonLabel" runat="server" Text='<%# Bind("SalesPerson") %>' /> <br /> EmailAddress: <asp:Label ID="EmailAddressLabel" runat="server" Text='<%# Bind("EmailAddress") %>' /> <br /> Phone: <asp:Label ID="PhoneLabel" runat="server" Text='<%# Bind("Phone") %>' /> <br /> PasswordHash: <asp:Label ID="PasswordHashLabel" runat="server" Text='<%# Bind("PasswordHash") %>' /> <br /> PasswordSalt: <asp:Label ID="PasswordSaltLabel" runat="server" Text='<%# Bind("PasswordSalt") %>' /> <br /> rowguid: <asp:Label ID="rowguidLabel" runat="server" Text='<%# Bind("rowguid") %>' /> <br /> ModifiedDate: <asp:Label ID="ModifiedDateLabel" runat="server" Text='<%# Bind("ModifiedDate") %>' /> <br /> <asp:LinkButton ID="EditButton" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit" /> </ItemTemplate> <PagerSettings Position="Top" /> <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" /> <RowStyle BackColor="#F7F6F3" ForeColor="#333333" /> </asp:FormView> </form>

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  • Unit Testing in Entity Framework 4 - using CreateSourceQuery

    - by Adam
    There are many great tutorials on abstracting your EF4 context so that it can be tested against (without involving a DB). Two great (and similar) examples are here: http://blogs.msdn.com/b/adonet/archive/2009/12/17/walkthrough-test-driven-development-with-the-entity-framework-4-0.aspx (oops, not enough rep. points to post second URL) basically you wind up querying your repository using linq-to-objects while testing, and linq-to-entities while running, and usually they behave the same, but when you start hitting more advanced functionality, problems arise. Here's the question. When using linq-to-objects against IObjectSet (ie, unit testing), CreateSourceQuery returns null, which will probably cause your entire query to crash and burn. ie O = db.Orders.First(); O.OrderItems.CreateSourceQuery().ToList(); Is there a way to get CreateSourceQuery to just return the underlying collection, rather than null when working with collections? Unfortunately EntityCollection is sealed, and so cannot be mocked. This isn't really the end or the world if EF4 won't let you abstract things to this level, I just wanted to make sure there wasn't something I was missing.

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  • Entity Framework 4 and SYSUTCDATETIME ()

    - by GIbboK
    Hi, I use EF4 and C#. I have a Table in my DataBase (MS SQL 2008) with a default value for a column SYSUTCDATETIME (). The Idea is to automatically add Date and Time as soon as a new record is Created. I create my Conceptual Model using EF4, and I have created an ASP.PAGE with a DetailsView Control in INSERT MODE. My problems: When I create a new Record. EF is not able to insert the actual Date and Time value but it inserts instead this value 0001-01-01 00:00:00.00. I suppose the EF is not able to use SYSUTCDATETIME () defined in my DataBase Any idea how to solve it? Thanks Here my SQL script CREATE TABLE dbo.CmsAdvertisers ( AdvertiserId int NOT NULL IDENTITY CONSTRAINT PK_CmsAdvertisers_AdvertiserId PRIMARY KEY, DateCreated dateTime2(2) NOT NULL CONSTRAINT DF_CmsAdvertisers_DateCreated DEFAULT sysutcdatetime (), ReferenceAdvertiser varchar(64) NOT NULL, NoteInternal nvarchar(256) NOT NULL CONSTRAINT DF_CmsAdvertisers_NoteInternal DEFAULT '' ); My Temporary solution: Please guys help me on this e.Values["DateCreated"] = DateTime.UtcNow; More info here: http://msdn.microsoft.com/en-us/library/bb387157.aspx How to use the default Entity Framework and default date values http://msdn.microsoft.com/en-us/library/dd296755.aspx

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  • Mapping composite foreign keys in a many-many relationship in Entity Framework

    - by Kirk Broadhurst
    I have a Page table and a View table. There is a many-many relationship between these two via a PageView table. Unfortunately all of these tables need to have composite keys (for business reasons). Page has a primary key of (PageCode, Version), View has a primary key of (ViewCode, Version). PageView obviously enough has PageCode, ViewCode, and Version. The FK to Page is (PageCode, Version) and the FK to View is (ViewCode, Version) Makes sense and works, but when I try to map this in Entity framework I get Error 3021: Problem in mapping fragments...: Each of the following columns in table PageView is mapped to multiple conceptual side properties: PageView.Version is mapped to (PageView_Association.View.Version, PageView_Association.Page.Version) So clearly enough, EF is having a complain about the Version column being a common component of the two foreign keys. Obviously I could create a PageVersion and ViewVersion column in the join table, but that kind of defeats the point of the constraint, i.e. the Page and View must have the same Version value. Has anyone encountered this, and is there anything I can do get around it? Thanks!

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  • Entity Framework - Store parent reference on child relationship (one -> many)

    - by contactmatt
    I have a setup like this: [Table("tablename...")] public class Branch { public Branch() { Users = new List<User>(); } [Key] public int Id { get; set; } public string Name { get; set; } public List<User> Users { get; set; } } [Table("tablename...")] public class User { [Key] public int Id {get; set; } public string Username { get; set; } public string Password { get; set; } [ForeignKey("ParentBranch")] public int? ParentBranchId { get; set; } // Is this possible? public Branch ParentBranch { get; set; } // ??? } Is it possible for the User to know what parent branch it belongs to? The code above is not working. Entity Framework version 5.0 .NET 4.0 c#

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  • Compiling .NET component that uses a non specific required version of a 3rd Party Vendor component

    - by Dan
    If someone were to develop a .NET component that relied on non specific versions of a vendor DLL - let's say it worked with My3rdPartyComponent.dll which is a .NET assembly, but it didn't matter which version. Some instances of classes found in this component would need to be passed into my component. Developers would reference my component dll but not have access to the source code. Basically, I want to be able to require the user to pass in an instance of 3rdPartyComponent.MyClass to my component functions but I do not care if it's version 1.1, 2.2, 2.23.980, etc of the 3rd party dll. Is there a way to do this while still typing the parameter I want to be passed in to my component? I don't want to use Object as the reference. In my component project I could specify SpecificVersion=True on the assembly reference. Will this solve my problem or will there be other 'dll hell' issues to deal with that I am not seeing?

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  • JSF don't find component in view root with the form id

    - by kenzokujpn
    I have a t:inputFileUpload inside the form, in the html of the display page the id of this component is form:inputFile but when I tried to get the component from the view root using "form:inputFile" the return is null, but when the "form:" is removed the return is the component. The component don't set the value in my managed bean, someone have this problem? EDIT: <h:form id="form" enctype="multipart/form-data"> <t:inputFileUpload id="inputFile" size="40" value="#{managedBean.inputFile}"/> </h:form> In the managed bean: private UploadedFile inputFile; with the gets and sets provided by Eclipse. //This method scans the view root and returns the component with the id passed as parameter findComponentInRoot("form:inputFile"); This returns null, but when I use: //This method scans the view root and returns the component with the id passed as parameter findComponentInRoot("inputFile"); The return is the component I'm looking for, but when I use the View Source in Internet Explorer the id of this component is "form:inputFile". I don't know if this is related, but the component don't set the value in my managed bean and it's strange the fact that the id of the component is different from the HTML source. I'm using JSF 1.2 Mojarra. Someone else has this problem? Or know why this happens?

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  • How to implement behavior in a component-based game architecture?

    - by ghostonline
    I am starting to implement player and enemy AI in a game, but I am confused about how to best implement this in a component-based game architecture. Say I have a following player character that can be stationary, running and swinging a sword. A player can transit to the swing sword state from both the stationary and running state, but then the swing must be completed before the player can resume standing or running around. During the swing, the player cannot walk around. As I see it, I have two implementation approaches: Create a single AI-component containing all player logic (either decoupled from the actual component or embedded as a PlayerAIComponent). I can easily how to enforce the state restrictions without creating coupling between individual components making up the player entity. However, the AI-component cannot be broken up. If I have, for example, an enemy that can only stand and walk around or only walks around and occasionally swing a sword, I have to create new AI-components. Break the behavior up in components, each identifying a specific state. I then get a StandComponent, WalkComponent and SwingComponent. To enforce the transition rules, I have to couple each component. SwingComponent must disable StandComponent and WalkComponent for the duration of the swing. When I have an enemy that only stands around, swinging a sword occasionally, I have to make sure SwingComponent only disables WalkComponent if it is present. Although this allows for better mix-and-matching components, it can lead to a maintainability nightmare as each time a dependency is added, the existing components must be updated to play nicely with the new requirements the dependency places on the character. The ideal situation would be that a designer can build new enemies/players by dragging components into a container, without having to touch a single line of engine or script code. Although I am not sure script coding can be avoided, I want to keep it as simple as possible. Summing it all up: Should I lob all AI logic into one component or break up each logic state into separate components to create entity variants more easily?

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  • Entity Framework Code First: Get Entities From Local Cache or the Database

    - by Ricardo Peres
    Entity Framework Code First makes it very easy to access local (first level) cache: you just access the DbSet<T>.Local property. This way, no query is sent to the database, only performed in already loaded entities. If you want to first search local cache, then the database, if no entries are found, you can use this extension method: 1: public static class DbContextExtensions 2: { 3: public static IQueryable<T> LocalOrDatabase<T>(this DbContext context, Expression<Func<T, Boolean>> expression) where T : class 4: { 5: IEnumerable<T> localResults = context.Set<T>().Local.Where(expression.Compile()); 6:  7: if (localResults.Any() == true) 8: { 9: return (localResults.AsQueryable()); 10: } 11:  12: IQueryable<T> databaseResults = context.Set<T>().Where(expression); 13:  14: return (databaseResults); 15: } 16: }

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  • How to use batch rendering with an entity component system?

    - by Kiril
    I have an entity component system and a 2D rendering engine. Because I have a lot of repeating sprites (the entities are non-animated, the background is tile based) I would really like to use batch rendering to reduce calls to the drawing routine. What would be the best way to integrate this with an engtity system? I thought about creating and populating the sprite batche every frame update, but that will probably be very slow. A better way would be to add a reference to an entity's quad to the sprite batch at initialization, but that would mean that the entity factory has to be aware of the Rendering System or that the sprite batch has to be a component of some Cache entity. One case violates encapsulation pretty heavily, while the other forces a non-game object entity in the entity system, which I am not sure I like a lot. As for engine, I am using Love2D (Love2D website) and FEZ ( FEZ website) as entity system(so everything is in Lua). I am more interested in a generic pattern of how to properly implement that rather than a language/library specific solution. Thanks in advance!

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  • Comments syntax for Idoc Script

    - by kyle.hatlestad
    Maybe this is widely known and I'm late to the party, but I just ran across the syntax for making comments in Idoc Script. It's been something I've been hoping to see for a long time. And it looks like it quietly snuck into the 10gR3 release. So for comments in Idoc Script, you simply [[% surround your comments in these symbols. %]] They can be on the same line or span multiple lines. If you look in the documentation, it still mentions making comments using the syntax. Well, that's certainly not an ideal approach. You're stuffing your comment into an actual variable, it's taking up memory, and you have to watch double-quotes in your comment. A perhaps better way in the old method is to start with my comments . Still not great, but now you're not assigning something to a variable and worrying about quotes. Unfortunately, this syntax only works in places that use the Idoc format. It can't be used in Idoc files that get indexed (.hcsp & .hcsf) and use the <!--$...--> format. For those, you'll need to continue using the older methods. While on the topic, I thought I would highlight a great plug-in to Notepad++ that Arnoud Koot here at Oracle wrote for Idoc Script. It does script highlighting as well as type-ahead/auto-completion for common variables, functions, and services. For some reason, I can never seem to remember if it's DOC_INFO_LATESTRELEASE or DOC_INFO_LATEST_RELEASE, so this certainly comes in handy. I've updated his plug-in to use this new comments syntax. You can download a copy of the plug-in here which includes installation instructions.

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  • Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 2 – Table per Type (TPT)

    - by mortezam
    In the previous blog post you saw that there are three different approaches to representing an inheritance hierarchy and I explained Table per Hierarchy (TPH) as the default mapping strategy in EF Code First. We argued that the disadvantages of TPH may be too serious for our design since it results in denormalized schemas that can become a major burden in the long run. In today’s blog post we are going to learn about Table per Type (TPT) as another inheritance mapping strategy and we'll see that TPT doesn’t expose us to this problem. Table per Type (TPT)Table per Type is about representing inheritance relationships as relational foreign key associations. Every class/subclass that declares persistent properties—including abstract classes—has its own table. The table for subclasses contains columns only for each noninherited property (each property declared by the subclass itself) along with a primary key that is also a foreign key of the base class table. This approach is shown in the following figure: For example, if an instance of the CreditCard subclass is made persistent, the values of properties declared by the BillingDetail base class are persisted to a new row of the BillingDetails table. Only the values of properties declared by the subclass (i.e. CreditCard) are persisted to a new row of the CreditCards table. The two rows are linked together by their shared primary key value. Later, the subclass instance may be retrieved from the database by joining the subclass table with the base class table. TPT Advantages The primary advantage of this strategy is that the SQL schema is normalized. In addition, schema evolution is straightforward (modifying the base class or adding a new subclass is just a matter of modify/add one table). Integrity constraint definition are also straightforward (note how CardType in CreditCards table is now a non-nullable column). Another much more important advantage is the ability to handle polymorphic associations (a polymorphic association is an association to a base class, hence to all classes in the hierarchy with dynamic resolution of the concrete class at runtime). A polymorphic association to a particular subclass may be represented as a foreign key referencing the table of that particular subclass. Implement TPT in EF Code First We can create a TPT mapping simply by placing Table attribute on the subclasses to specify the mapped table name (Table attribute is a new data annotation and has been added to System.ComponentModel.DataAnnotations namespace in CTP5): public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } [Table("BankAccounts")] public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } } [Table("CreditCards")] public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; } } If you prefer fluent API, then you can create a TPT mapping by using ToTable() method: protected override void OnModelCreating(ModelBuilder modelBuilder) {     modelBuilder.Entity<BankAccount>().ToTable("BankAccounts");     modelBuilder.Entity<CreditCard>().ToTable("CreditCards"); } Generated SQL For QueriesLet’s take an example of a simple non-polymorphic query that returns a list of all the BankAccounts: var query = from b in context.BillingDetails.OfType<BankAccount>() select b; Executing this query (by invoking ToList() method) results in the following SQL statements being sent to the database (on the bottom, you can also see the result of executing the generated query in SQL Server Management Studio): Now, let’s take an example of a very simple polymorphic query that requests all the BillingDetails which includes both BankAccount and CreditCard types: projects some properties out of the base class BillingDetail, without querying for anything from any of the subclasses: var query = from b in context.BillingDetails             select new { b.BillingDetailId, b.Number, b.Owner }; -- var query = from b in context.BillingDetails select b; This LINQ query seems even more simple than the previous one but the resulting SQL query is not as simple as you might expect: -- As you can see, EF Code First relies on an INNER JOIN to detect the existence (or absence) of rows in the subclass tables CreditCards and BankAccounts so it can determine the concrete subclass for a particular row of the BillingDetails table. Also the SQL CASE statements that you see in the beginning of the query is just to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type) TPT ConsiderationsEven though this mapping strategy is deceptively simple, the experience shows that performance can be unacceptable for complex class hierarchies because queries always require a join across many tables. In addition, this mapping strategy is more difficult to implement by hand— even ad-hoc reporting is more complex. This is an important consideration if you plan to use handwritten SQL in your application (For ad hoc reporting, database views provide a way to offset the complexity of the TPT strategy. A view may be used to transform the table-per-type model into the much simpler table-per-hierarchy model.) SummaryIn this post we learned about Table per Type as the second inheritance mapping in our series. So far, the strategies we’ve discussed require extra consideration with regard to the SQL schema (e.g. in TPT, foreign keys are needed). This situation changes with the Table per Concrete Type (TPC) that we will discuss in the next post. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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  • Cyclic References and WCF

    - by Kunal
    I have generated my POCO entities using POCO Generator, I have more than 150+ tables in my database. I am sharing POCO entities all across the application layers including the client. I have disabled both LazyLoading and ProxyCreation in my context.I am using WCF on top of my data access and business layer. Now, When I return a poco entity to my client, I get an error saying "Underlying connection was closed" I enabled WCF tracing and found the exact error : Contains cycles and cannot be serialized if reference tracking is disabled. I Looked at MSDN and found solutions like setting IsReference=true in the DataContract method atttribute but I am not decorating my POCO classes with DataContracts and I assume there is no need of it as well. I won't be calling that as a POCO if I decorate a class with DataContract attribute Then, I found solutions like applying custom attribute [CyclicReferenceAware] over my ServiceContracts.That did work but I wanted to throw this question to community to see how other people managed this and also why Microsoft didn't give built in support for figuring out cyclic references while serializing POCO classes

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  • Entity Framework and layer separation

    - by Thomas
    I'm trying to work a bit with Entity Framework and I got a question regarding the separation of layers. I usually use the UI - BLL - DAL approach and I'm wondering how to use EF here. My DAL would usually be something like GetPerson(id) { // some sql return new Person(...) } BLL: GetPerson(id) { Return personDL.GetPerson(id) } UI: Person p = personBL.GetPerson(id) My question now is: since EF creates my model and DAL, is it a good idea to wrap EF inside my own DAL or is it just a waste of time? If I don't need to wrap EF would I still place my Model.esmx inside its own class library or would it be fine to just place it inside my BLL and work some there? I can't really see the reason to wrap EF inside my own DAL but I want to know what other people are doing. So instead of having the above, I would leave out the DAL and just do: BLL: GetPerson(id) { using (TestEntities context = new TestEntities()) { var result = from p in context.Persons.Where(p => p.Id = id) select p; } } What to do?

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  • Entity communication: Message queue vs Publish/Subscribe vs Signal/Slots

    - by deft_code
    How do game engine entities communicate? Two use cases: How would entity_A send a take-damage message to entity_B? How would entity_A query entity_B's HP? Here's what I've encountered so far: Message queue entity_A creates a take-damage message and posts it to entity_B's message queue. entity_A creates a query-hp message and posts it to entity_B. entity_B in return creates an response-hp message and posts it to entity_A. Publish/Subscribe entity_B subscribes to take-damage messages (possibly with some preemptive filtering so only relevant message are delivered). entity_A produces take-damage message that references entity_B. entity_A subscribes to update-hp messages (possibly filtered). Every frame entity_B broadcasts update-hp messages. Signal/Slots ??? entity_A connects an update-hp slot to entity_B's update-hp signal. Something better? Do I have a correct understanding of how these communication schemes would tie into a game engine's entity system? How do entities in commercial game engines communicate?

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  • Entity Framework 4 "Generate Database from Model" to SQLEXPRESS mdf results in "Could not locate ent

    - by InfinitiesLoop
    I'm using Visual Studio 2010 RTM. I want to do model-first, so I started a new MVC app and added a new blank edmx. Created a few entities. No problem. Then I "Generate Database from Model", and allow the dialog to create a new database for me, which it does successfully as 'mydatabase.mdf' in the app's App_Data directory. Then I open the generated sql file (in Visual Studio). To run it of course I have to give it a connection. I am not sure if it's right, but I used '.\SQLEXPRESS' and Windows authentication. No idea how I'd tell it where the MDF is. Then the problem -- upon executing it, I get: Msg 911, Level 16, State 1, Line 1 Could not locate entry in sysdatabases for database 'mydatabase'. No entry found with that name. Make sure that the name is entered correctly. And indeed there were no tables created in the MDF. So... what am I doing wrong, or am I off my rocker expecting this to work? :)

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  • generate only objectLayer of Entity Framework Model by edmgen tool

    - by loviji
    How to generate only objectLayer by edmgen tool, without generating csdl, ssdl and views ? *"%windir%\Microsoft.NET\Framework\v4.0.30319\edmgen.exe" /mode:fullgeneration /c:"Data Source=.\sqlexpress; Initial Catalog=uqs; Integrated Security=SSPI" /project:generateEntityModel /entitycontainer:uqsEntities /namespace:uqsModel /language:CSharp /outobjectlayer:"D:/uqsObjectLayer.cs" * in this script I don't write location to write csdl, ssdl and views , but they are generated in C:\Users\adminUser in windows Vista and objectLayer generated to D:/uqsObjectLayer.cs. If I use /mode:EntityClassGeneration, this option requires the /incsdl argument and either the /project argument or the /outobjectlayer argument. The /language argument is optional. But I don't want use csdl file. As I understand, edmgen.tool can not create objectlayer without csdl file. Now is there alternate way or tool for generating objectlayer from db?

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  • UDF call in entity framework is cached

    - by Fred Yang
    I am doing a test after reading an article http://blogs.msdn.com/alexj/archive/2009/08/07/tip-30-how-to-use-a-custom-store-function.aspx about udf function called. When I use a function with objectContext.Entities.Where( t= udf(para1, para2) == 1), here the Entities is not ObjectQuery, but an ObjectSet, the first time I call the method, it runs correctly, if I reuse the objectContext,and run it again but with different para1, para2, then the previous parameter values still cached, and the result is same as previous one, which is wrong. The sql profiler shows that both query hit the database, but the t-sql is the same. Am I missing something? And the ObjectSet does not support .where(esql_string). How to get udf working with ObjectSet? Thanks Fred

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  • Error reached after genereated entity framework classes by edmgen tool

    - by loviji
    Hello, First I read this question, but this knowledge did not help to solve my problems. In initial I've created edmx file by Visual Studio. Generated files with names: uqsModel.Designer.cs uqsModel.edmx This files are located on App_Code folder. And my web app work normally. In Web Config generated connectionstring automatically. <add name="uqsEntities" connectionString="metadata=res://*/App_Code.uqsModel.csdl|res://*/App_Code.uqsModel.ssdl|res://*/App_Code.uqsModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=aemloviji\sqlexpress;Initial Catalog=uqs;Integrated Security=True;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" /></connectionStrings> Then I had to generate classes by the instrument edmgen tool(full generation mode). Generated new files with names: uqsModel.cs uqsModel.csdl uqsModel.msl uqsModel.ssdl uqsViews.cs it save new classed to the folder where edmx files located before, and remove existing edmx files. And when page redirrects to any web page server side code fails. And problem: Unable to load the specified metadata resource. Some idea, please.

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  • Entity Framework - Optimistic Concurrency Issue

    - by Cranialsurge
    I have a windows service that runs every 10 seconds ... each time it runs, it takes some test data, modifies it and persists it to the database using the EntityFramework. However, on every second run, when I try to persist the change I get the following Optimistic Concurrency Exception:- Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries I know for a fact that there is nothing else writing to that DB but my service which updates records every 10 seconds. What could be causing the concurrency exception here ?

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  • Entity Framework - MySQL - Datetime format issue

    - by effkay
    Hello; I have a simple table with few date fields. Whenever I run following query: var docs = ( from d in base.EntityDataContext.document_reviews select d ).ToList(); I get following exception: Unable to convert MySQL date/time value to System.DateTime. MySql.Data.Types.MySqlConversionException: Unable to convert MySQL date/time value to System.DateTime The document reviews table has two date/time fields. One of them is nullable. I have tried placing following in connection string: Allow Zero Datetime=true; But I am still getting exception. Anyone with a solution?

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  • Unable to specify abstract classes in TPH hierarchy in Entity Framework 4

    - by Lee Atkinson
    Hi I have a TPH heirachy along the lines of: A-B-C-D A-B-C-E A-F-G-H A-F-G-I I have A as Abstract, and all the other classes are concrete with a single discriminator column. This works fine, but I want C and G to be abstract also. If I do that, and remove their discriminators from the mapping, I get error 3034 'Two entities with different keys are mapped to the same row'. I cannot see how this statement can be correct, so I assume it's a bug in some way. Is it possible to do the above? Lee

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  • Entity Relationship Multiple 1:1's

    - by Evan
    I have an application where I have a generic object (table) called Hull. Each hull in the table is unique. I have another object that has three hulls, but they are specifically the Port_Hull, Center_Hull and Starboard_Hull. Rather than create a One to Many relationship, I was trying to create a one to one relationship for each one, but this results in numerous errors unless I make the relationship from Hull to Vessel one to many (which it is not). Any idea how I go about this, or should I abandon the concept and make the vessel to hull relationship one to many and deal with lists that always have three entries? p.s. Using uniqueidentifiers as many users can be adding records while disconnected. Hull Table HullID uniqueidentifier (primary key) plus bunch of hull data fields Vessel Table VesselID uniqueidentifier (primary key) MainHullID uniqueidentifier (tried as key and non-key) PortHullID uniqueidentifier StarboardHullID uniqueidentifier plus bunch of Vessel data fields

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