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  • SQL SERVER – Creating All New Database with Full Recovery Model

    - by pinaldave
    Sometimes, complex problems have very simple solutions. Let us see the following email which I received recently. “Hi Pinal, In our system when we create new database, by default, they are all created with the Simple Recovery Model. We have to manually change the recovery model after we create the database. We used the following simple T-SQL code: CREATE DATABASE dbname. We are very frustrated with this situation. We want all our databases to have the Full Recovery Model option by default. We are considering the following methods; please suggest the most efficient one among them. 1) Creating a Policy; when it is violated, the database model can be fixed 2) Triggers at Server Level 3) Automated Job which goes through all the databases and checks their recovery model; if the DBA has not changed the model, then the job will list the Databases and change their recovery model Also, we have a situation where we need a database in the Simple Recovery Model as well – how to white list them? Please suggest the best method.” Indeed, an interesting email! The answer to their question, i.e., which is the best method to fit their needs (white list, default, etc)? It will be NONE of the above. Here is the solution in one line and also the easiest way: Just go to your Model database: Path in SSMS >> Databases > System Databases >> model >> Right Click Properties >> Options >> Recovery Model - Select Full from dropdown. Every newly created database takes its base template from the Model Database. If you create a custom SP in the Model Database, when you create a new database, it will automatically exist in that database. Any database that was already created before making changes in the Model Database will not be affected at all. Creating Policy is also a good method, and I will blog about this in a separate blog post, but looking at current specifications of the reader, I think the Model Database should be modified to have a Full Recovery Option. While writing this blog post, I remembered my another blog post where the model database log file was growing drastically even though there were no transactions SQL SERVER – Log File Growing for Model Database – model Database Log File Grew Too Big. NOTE: Please do not touch the Model Database unnecessary. It is a strict “No.” If you want to create an object that you need in all the databases, then instead of creating it in model database, I suggest that you create a new database called maintenance and create the object there. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, Readers Question, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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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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  • Any good C++ Component/Entity frameworks?

    - by Pat
    (Skip to the bold if you want to get straight to my question :) ) I've been dabbling in the different technologies available out there to use. I tried Unity and component based design, managing to get a little guy up and running around a map with basic pathfinding. I really loved how easy it was to program using components, but I wanted a bit more control and something more 2D friendly, so I went with LibGDX. I looked around and found 2 good frameworks for Java, which are Artemis and Apollo. I didn't like Artemis much, so I went with Apollo, which I loved. I managed to integrate it with Box2D and get a little guy running around bouncing balls. Great! But since I want to try out most of the options, there is still C++/SFML that I haven't tried yet. Coming from a Java/C# background, I've always wanted to get my hands dirty with C++. But then, after some looking around, I noticed there aren't any Component-Based frameworks for me to use. There's a somewhat done porting of Artemis, but, aside from not being completely finished, I didn't quite like Artemis even in Java. I found Apollo's approach much more.. logical. So, my question is, are there any good Component/Entity frameworks for C++ that I can use that are similar to Artemis, or preferably, Apollo?

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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 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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  • Anemic Domain Model, Business Logic and DataMapper (PHP)

    - by sunwukung
    I've implemented a rudimentary ORM layer based on DataMapper (I don't want to use a full blown ORM like Propel/Doctrine - for anything beyond simple fetch/save ops I prefer to access the data directly layer using a SQL abstraction layer). Following the DataMapper pattern, I've endeavoured to keep all persistence operations in the Mapper - including the location of related entities. My Entities have access to their Mapper, although I try not to call Mapper logic from the Entity interface (although this would be simple enough). The result is: // get a mapper and produce an entity $ProductMapper = $di->get('product_mapper'); $Product = $ProductMapper->find('[email protected]','email'); //.. mutaute some values.. save $ProductMapper->save($Product) // uses __get to trigger relation acquisition $Manufacturer = $Product->manufacturer; I've read some articles regarding the concept of an Anemic Domain model, i.e. a Model that does not contain any "business logic". When demonstrating the sort of business logic ideally suited to a Domain Model, however, acquiring related data items is a common example. Therefore I wanted to ask this question: Is persistence logic appropriate in Domain Model objects?

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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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  • override delete function in entity framework

    - by k0ni
    How can i make my own delete method to prevent that the data really gets deleted? i want to set a datetime field when it gets deleted insted of a normal delete. i read about overriding the submitchanges function, but i don't get it to work thanks

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  • How to create relationship between two tables with revisions using Entity Framework

    - by Chris Ridenour
    So I am in the process of redesigning a small database (and potentially a much larger one) but want to show the value of using revisions / history of the business objects. I am switching the data from Access to MSSQL 2008. I am having a lot of internal debate on what version of "revision history" to use in the design itself - and thought I had decided to add a "RevisionId" to all tables. With this design - adding a RevisionId to all tables we would like tracked - what would be the best way to create Navigational Properties and Relationships between two tables such as | Vendor | VendorContact | where a Vendor can have multiple contacts. The Contacts themselves will be under revision. Will it require custom extensions or am I over thinking this? Thanks in advance.

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  • DeleteObject method is missing in Entity Framework 4.1

    - by bobetko
    This is driving me crazy. I am getting error that object doesn't contain definition for DeleteObject. Here is my line of code that produces an error: ctx.Tanks.DeleteObject(Tank); I tried to reference another object from another edmx file that my friend has created and then everything is fine, DeleteObject exists. I don't think I miss any references in my project. And project itself contains edmx file and I used DBContext to create POCOs. Any ideas?

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  • Missing something with Entity Framework for .NET 3.5?

    - by AC
    Is it not possible to have EF create the necessary entities when I have two related tables linked with a FK in .NET3.5SP1? I see where the checkbox to support this is disabled but it is available in .NET4. I've got a DB that has only tables with relationships in it. I need to build a Silverlight app (SL4) that allows management of the data within this app. I can't use .NET4 on the server... only .NET3.5SP1 so FK relationship bit in EF4 isn't available to me. Looking to avoid building as much of the plumbing to get back to the DB from the SL4 app as possible...

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  • Entity Framework 5 upgrade from 4

    - by user1714591
    I'm having an issue with the Where clause in a search, in my original version EF4 I could add a Where clause with 2 parameters, the where clause (string predicate) and a ObjectParameter list such as var query = context.entities.Where(WhereClause.ToString(), Params.ToArray()); since my upgrade to EF5 I don't seem to have that option am I missing something? This was originally used to build dynamic where clause such as "it.entity_id = @entity_id" then holding the variable value in the ObjectParameter. I'm hoping I don't have to rewrite all the searches that have been built out this way, so any assistance would be greatly appreciated. Cheers

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  • Entity Framework 4 - Delete Object

    - by GibboK
    I have 3 Tables in my DataBase CmsMasterPages CmsMasterPagesAdvSlots (Pure Juction Table) CmsAdvSlots Here a Picture of my EDM: I need find out all objects CmsAdvSlot connected with a CmsMasterPage (it is working in my code posted belove), and DELETE the result (CmsAdvSlot) from the DataBase. My Problem is I am not able to DELETE this Objects when I found theme. Error: The object cannot be deleted because it was not found in the ObjectStateManager. int findMasterPageId = Convert.ToInt32(uxMasterPagesListSelector.SelectedValue); CmsMasterPage myMasterPage = context.CmsMasterPages.FirstOrDefault(x => x.MasterPageId == findMasterPageId); var resultAdvSlots = myMasterPage.CmsAdvSlots; // It is working until here foreach (var toDeleteAdv in resultAdvSlots) { context.DeleteObject(myMasterPage.CmsAdvSlots.Any()); // ERORR HERE!! context.SaveChanges(); } Any idea how to solve it? Thanks for your time! :-)

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  • Entity Framework 4.0 GetChanges() equivalent

    - by Jonathan
    Hi In LINQ to SQL, you can override SubmitChanges and use the method this.GetChangeSet() to get all the inserts, updates and deletes so that you can make last minute changes before it is committed to the database. Can this be done in EF 4.0? I see there is a override for SaveChanges but I need to know the equivalent for GetChangeSet()

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  • Entity Framework - Self Tracking Objects - how to reset client side?

    - by David
    I am using wcf with self tracking entity framework objects. On the client side i have bound an entity to an edit form (which has multiple textboxes and comboboxes). After the user hits Save, the entity is sent through wcf to the server wcf service which will attempt to save the entity. If there is a failure (say a network failure), I need to reset the current entity back to original values. How best can I do this client side? (I recognize with Self Tracking objects there is a property OriginalValues however that collection seems to have count=0) so not sure how to get the original values? Thanks-

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  • Extracting the Date from a DateTime in Entity Framework 4 and LINQ

    - by Ken Cox [MVP]
    In my current ASP.NET 4 project, I’m displaying dates in a GridDateTimeColumn of Telerik’s ASP.NET Radgrid control. I don’t care about the time stuff, so my DataFormatString shows only the date bits: <telerik:GridDateTimeColumn FilterControlWidth="100px"   DataField="DateCreated" HeaderText="Created"    SortExpression="DateCreated" ReadOnly="True"    UniqueName="DateCreated" PickerType="DatePicker"    DataFormatString="{0:dd MMM yy}"> My problem was that I couldn’t get the built-in column filtering (it uses Telerik’s DatePicker control) to behave.  The DatePicker assumes that the time is 00:00:00 but the data would have times like 09:22:21. So, when you select a date and apply the EqualTo filter, you get no results. You would get results if all the time portions were 00:00:00. In essence, I wanted my Entity Framework query to give the DatePicker what it wanted… a Date without the Time portion. Fortunately, EF4 provides the TruncateTime  function. After you include Imports System.Data.Objects.EntityFunctions You’ll find that your EF queries will accept the TruncateTime function. Here’s my routine: Protected Sub RadGrid1_NeedDataSource _     (ByVal source As Object, _      ByVal e As Telerik.Web.UI.GridNeedDataSourceEventArgs) _     Handles RadGrid1.NeedDataSource     Dim ent As New OfficeBookDBEntities1     Dim TopBOMs = From t In ent.TopBom, i In ent.Items _                   Where t.BusActivityID = busActivityID _       And i.BusActivityID And t.ItemID = i.RecordID _       Order By t.DateUpdated Descending _       Select New With {.TopBomID = t.TopBomID, .ItemID = t.ItemID, _                        .PartNumber = i.PartNumber, _                        .Description = i.Description, .Notes = t.Notes, _                        .DateCreated = TruncateTime(t.DateCreated), _                        .DateUpdated = TruncateTime(t.DateUpdated)}     RadGrid1.DataSource = TopBOMs End Sub Now when I select March 14, 2011 on the DatePicker, the filter doesn’t stumble on time values that don’t make sense. Full Disclosure: Telerik gives me (and other developer MVPs) free copies of their suite.

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