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  • Adding existing entity to navigation property of a different entity

    - by Shay Friedman
    I'm using EF4 and I'm running into a problem when I try to do something that looks quite trivial to me. I have two entities, let's call them A and B. These entities have a many-to-many association between them with a navigation property on A that contains a list of related B entities. What I want to do is to add existing B entities to a new A entity. When I try to do that, I get an exception: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. Has anyone run into such a problem?

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  • Need to debug LINQ simple queries in Visual Studio 2010

    - by maxima120
    I often get in a position when I need to know why my LINQ doesnt work as intended... I use object collections and extensions. I dont want spend more than couple of minutes on it. LINQ supposed to make developer's life easier not harder. I hoped VS 2010 will have it fixed but I now use RC and it still doesnt let me type LINQ and check what is going on... Says as before "Expression cannot contain lambda expressions"... Is there some add-on for Visual Studio so I can quickly and effectively run ad-hoc queries and find out what is going on and where I am wrong?

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  • ASP.NET MVC 3 Linq uppercase or lowercase database search

    - by user1495557
    I need immediate help. ): and i know little english. ASP.NET MVC 3 Linq uppercase or lowercase contains search Example: string metin="baris"; var IcerikAra = (from icerik in Context.dbDokumanEditor join kategori in Context.dbDokumanKategori on icerik.KategoriID equals kategori.KategoriID where icerik.Icerik.toLower().Contains(metin) select new { KategoriID=kategori. KategoriAd=kategori.KategoriAd }).ToList(); Exception: StackTrace: at System.Data.EntityClient.EntityCommandDefinition.ExecuteStoreCommands(EntityCommandentityCommand, CommandBehavior behavior) at System.Data.Objects.Internal.ObjectQueryExecutionPlan.Execute[TResultType](ObjectContext context, ObjectParameterCollection parameterValues) at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable.GetEnumerator() at System.Data.Entity.Internal.Linq.InternalQuery`1.GetEnumerator() at System.Data.Entity.Infrastructure.DbQuery`1.System.Collections.Generic.IEnumerable.GetEnumerator() at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source) at Plus.Areas.DokumanEditor.Controllers.DokumanController.DokumanIcerikAramaBaslat(String metin) Error Message: An error occurred while executing the command definition. See the inner exception for details. thanks..

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  • Deleting entity with child relationships using .Net Entity Framework problem

    - by Am
    My God, EF is so frustrating. I can't seem to be able to get my head around what I need to do so I can delete an object. I seem to be able to remove the object but not the related child objects. Can anyone tell me what is the rule of thumb when you want to delete all related child objects of a given object? I've tried loading all related objects like this: if (!object.childobjects.IsLoaded) object.childobjects.Load(); but once I do the following I get errors related to the relationships: modelcontext.DeleteObject(object); modelcontext.SaveChanges(); Why can't I just load the object using modelcontext.GetObjectByKey and remove it along with its child objects? My other question is can I delete an object using Entity command like so? DELETE e from objectset as e where e.id = 12 I've tried few variations and all of them throw exceptions.

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  • Linq to NHibernate, Order by Rand() ?

    - by Felipe
    Hi everybody, I'm using Linq To Nhibernate, and with a HQL statement I can do something like this: string hql = "from Entity e order by rand()"; Andi t will be ordered so random, and I'd link to know How can I do the same statement with Linq to Nhibernate ? I try this: var result = from e in Session.Linq<Entity> orderby new Random().Next(0,100) select e; but it throws a exception and doesn't work... is there any other way or solution? Thanks Cheers

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  • Querying a Single Column with LINQ

    - by Hossein Margani
    Hi Every one! I want to fetch array of values of a single column in a table, for example, I have a table named Customer(ID,Name), and want to fetch ids of all customers. my query in LINQ is: var ids = db.Customers.Select(c=>c.ID).ToList(); The answer of this query is correct, but I ran SQL Server Profiler, and saw the query which was like this: SELECT [t0].[ID], [t0].[Name] FROM [dbo].[Customer] AS [t0] I understood that LINQ selects all columns and then creates the integer array of ID fields. How can I write a LINQ query which generates this query in SQL Server: SELECT [t0].[ID] FROM [dbo].[Customer] AS [t0] Thank you.

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  • RIA Services - Two entity models share an entity name

    - by Alex
    I have two entity models hooked up to two different databases. However, the two databases both have a table named 'brand', for example. As such, there is a naming conflict in my models. Now, I've been able to add a namespace to each model, via Custom Tool Namespace in the model's properties, but the generated code in my Silverlight project will try to use both namespaces, and come up with this, Imports MyProject.ModelA Imports MyProject.ModelB Public ReadOnly Property brands() As EntitySet(Of brand) Get Return MyBase.EntityContainer.GetEntitySet(Of brand) End Get End Property giving me this exception: 'Error 1 'brand' is ambiguous, imported from the namespaces or types 'MyProject.ModelA,MyProject.ModelB'. Has anyone had experience with naming conflicts like this using RIA services? How did you solve it?

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  • LINQ to Entities and Business / Validation Rules

    - by Chris
    We have a requirement where we need to allow users to dynamically create custom reports that will run against our database and return sets of data. It would be something similar to this: http://www.marcuswhitworth.com/2009/12/dynamic-linq-with-expression-trees/ but would ultimately contain the ability to create more complicated logic. I believe LINQ to Entities might possibly allow us to do something like we're attempting to achieve. I should note that these reports are going to need to run against multiple tables. Can anyone point me in the right direction for something like this? Has anyone done anything similar with LINQ to Entities?

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  • NHibernate Linq - Duplicate Records

    - by adegiamb
    I am having a problem with duplicate blog post coming back when i run the linq statement below. The issue that a blog post can have the same tag more then once and that's causing the problem. I know when you use criteria you can do the followingcriteria.SetResultTransformer(new DistinctRootEntityResultTransformer()); How can I do the same thing with linq? List<BlogPost> result = (from blogPost in _session.Linq<BlogPost>() from tags in blogPost.Tags where tags.Tag == tag && blogPost.IsPublished && blogPost.Slug != slugToExclude orderby blogPost.DateCreated descending select blogPost).Distinct() .Skip(recordsToSkip).Take(pageSize).ToList();

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  • Entity Framework 4.1 auto generate with DbContext when creating ADO.NET Entity Data Model

    - by smudgedlens
    I would like to work with DbContext instead of ObjectContext. I updated EF so now I have the DbContext, but I want to generate my strongly-typed context based on the DbContext and not the ObjectContext. When I add new ADO.NET Entity Data Model, it is still based on the ObjectContext. Is it not possible to have it base off of DbContext in Visual Studio 2010 with EF 4.1? UPDATE: Okay, I followed the directions in this link and was able to generate the DbContext template objects. However, now it is saying there is ambiguity between the template entities and the entities in my .edmx file. How do I resovle this? Do I blow away the ones in the .edmx file?

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  • linq with Include and criteria

    - by JMarsch
    How would I translate this into LINQ? Say I have A parent table (Say, customers), and child (addresses). I want to return all of the Parents who have addresses in California, and just the california address. (but I want to do it in LINQ and get an object graph of Entity objects) Here's the old fashioned way: SELECT c.blah, a.blah FROM Customer c INNER JOIN Address a on c.CustomerId = a.CustomerId where a.State = 'CA' The problem I'm having with LINQ is that i need an object graph of concrete Entity types (and it can't be lazy loaded. Here's what I've tried so far: // this one doesn't filter the addresses -- I get the right customers, but I get all of their addresses, and not just the CA address object. from c in Customer.Include(c = c.Addresses) where c.Addresses.Any(a = a.State == "CA") select c // this one seems to work, but the Addresses collection on Customers is always null from c in Customer.Include(c = c.Addresses) from a in c.Addresses where a.State == "CA" select c; Any ideas?

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  • Linq 2 SQL using base class and WCF

    - by Gena Verdel
    Hi all. I have the following problem: I'm using L2S for generating entity classes. All these classes share the same property ID which is autonumber. So I figured to put this property to base class and extend all entity classes from the base one. In order to be able to read the value I'm using the override modifier on this property in each and every entity class. Up to now it's live and kicking. Then I decided to introduce another tier - services using WCF approach. I've modified the Serialization mode to Unidirectional (and added the IsReference=true attribute to enable two directions), also added [DataContract] attribute to the BaseObject class. WCF is able to transport the whole object but one property , which is ID. Applying [DataMember] attribute on ID property at the base class resulted in nothing. Am I missing something? Is what I'm trying to achieve possible at all? [DataContract()] abstract public class BaseObject : IIccObject public virtual long ID { get; set; } [Table(Name="dbo.Blocks")] [DataContract(IsReference=true)] public partial class Block : INotifyPropertyChanging, INotifyPropertyChanged { private static PropertyChangingEventArgs emptyChangingEventArgs = new PropertyChangingEventArgs(String.Empty); private long _ID; private int _StatusID; private string _Name; private bool _IsWithControlPoints; private long _DivisionID; private string _SHAPE; private EntitySet<BlockByWorkstation> _BlockByWorkstations; private EntitySet<PlanningPointAppropriation> _PlanningPointAppropriations; private EntitySet<Neighbor> _Neighbors; private EntitySet<Neighbor> _Neighbors1; private EntitySet<Task> _Tasks; private EntitySet<PlanningPointByBlock> _PlanningPointByBlocks; private EntityRef<Division> _Division; private bool serializing; #region Extensibility Method Definitions partial void OnLoaded(); partial void OnValidate(System.Data.Linq.ChangeAction action); partial void OnCreated(); partial void OnIDChanging(long value); partial void OnIDChanged(); partial void OnStatusIDChanging(int value); partial void OnStatusIDChanged(); partial void OnNameChanging(string value); partial void OnNameChanged(); partial void OnIsWithControlPointsChanging(bool value); partial void OnIsWithControlPointsChanged(); partial void OnDivisionIDChanging(long value); partial void OnDivisionIDChanged(); partial void OnSHAPEChanging(string value); partial void OnSHAPEChanged(); #endregion public Block() { this.Initialize(); } [Column(Storage="_ID", AutoSync=AutoSync.OnInsert, DbType="BigInt NOT NULL IDENTITY", IsPrimaryKey=true, IsDbGenerated=true)] [DataMember(Order=1)] public override long ID { get { return this._ID; } set { if ((this._ID != value)) { this.OnIDChanging(value); this.SendPropertyChanging(); this._ID = value; this.SendPropertyChanged("ID"); this.OnIDChanged(); } } } [Column(Storage="_StatusID", DbType="Int NOT NULL")] [DataMember(Order=2)] public int StatusID { get { return this._StatusID; } set { if ((this._StatusID != value)) { this.OnStatusIDChanging(value); this.SendPropertyChanging(); this._StatusID = value; this.SendPropertyChanged("StatusID"); this.OnStatusIDChanged(); } } } [Column(Storage="_Name", DbType="NVarChar(255)")] [DataMember(Order=3)] public string Name { get { return this._Name; } set { if ((this._Name != value)) { this.OnNameChanging(value); this.SendPropertyChanging(); this._Name = value; this.SendPropertyChanged("Name"); this.OnNameChanged(); } } } [Column(Storage="_IsWithControlPoints", DbType="Bit NOT NULL")] [DataMember(Order=4)] public bool IsWithControlPoints { get { return this._IsWithControlPoints; } set { if ((this._IsWithControlPoints != value)) { this.OnIsWithControlPointsChanging(value); this.SendPropertyChanging(); this._IsWithControlPoints = value; this.SendPropertyChanged("IsWithControlPoints"); this.OnIsWithControlPointsChanged(); } } } [Column(Storage="_DivisionID", DbType="BigInt NOT NULL")] [DataMember(Order=5)] public long DivisionID { get { return this._DivisionID; } set { if ((this._DivisionID != value)) { if (this._Division.HasLoadedOrAssignedValue) { throw new System.Data.Linq.ForeignKeyReferenceAlreadyHasValueException(); } this.OnDivisionIDChanging(value); this.SendPropertyChanging(); this._DivisionID = value; this.SendPropertyChanged("DivisionID"); this.OnDivisionIDChanged(); } } } [Column(Storage="_SHAPE", DbType="Text", UpdateCheck=UpdateCheck.Never)] [DataMember(Order=6)] public string SHAPE { get { return this._SHAPE; } set { if ((this._SHAPE != value)) { this.OnSHAPEChanging(value); this.SendPropertyChanging(); this._SHAPE = value; this.SendPropertyChanged("SHAPE"); this.OnSHAPEChanged(); } } } [Association(Name="Block_BlockByWorkstation", Storage="_BlockByWorkstations", ThisKey="ID", OtherKey="BlockID")] [DataMember(Order=7, EmitDefaultValue=false)] public EntitySet<BlockByWorkstation> BlockByWorkstations { get { if ((this.serializing && (this._BlockByWorkstations.HasLoadedOrAssignedValues == false))) { return null; } return this._BlockByWorkstations; } set { this._BlockByWorkstations.Assign(value); } } [Association(Name="Block_PlanningPointAppropriation", Storage="_PlanningPointAppropriations", ThisKey="ID", OtherKey="MasterBlockID")] [DataMember(Order=8, EmitDefaultValue=false)] public EntitySet<PlanningPointAppropriation> PlanningPointAppropriations { get { if ((this.serializing && (this._PlanningPointAppropriations.HasLoadedOrAssignedValues == false))) { return null; } return this._PlanningPointAppropriations; } set { this._PlanningPointAppropriations.Assign(value); } } [Association(Name="Block_Neighbor", Storage="_Neighbors", ThisKey="ID", OtherKey="FirstBlockID")] [DataMember(Order=9, EmitDefaultValue=false)] public EntitySet<Neighbor> Neighbors { get { if ((this.serializing && (this._Neighbors.HasLoadedOrAssignedValues == false))) { return null; } return this._Neighbors; } set { this._Neighbors.Assign(value); } } [Association(Name="Block_Neighbor1", Storage="_Neighbors1", ThisKey="ID", OtherKey="SecondBlockID")] [DataMember(Order=10, EmitDefaultValue=false)] public EntitySet<Neighbor> Neighbors1 { get { if ((this.serializing && (this._Neighbors1.HasLoadedOrAssignedValues == false))) { return null; } return this._Neighbors1; } set { this._Neighbors1.Assign(value); } } [Association(Name="Block_Task", Storage="_Tasks", ThisKey="ID", OtherKey="BlockID")] [DataMember(Order=11, EmitDefaultValue=false)] public EntitySet<Task> Tasks { get { if ((this.serializing && (this._Tasks.HasLoadedOrAssignedValues == false))) { return null; } return this._Tasks; } set { this._Tasks.Assign(value); } } [Association(Name="Block_PlanningPointByBlock", Storage="_PlanningPointByBlocks", ThisKey="ID", OtherKey="BlockID")] [DataMember(Order=12, EmitDefaultValue=false)] public EntitySet<PlanningPointByBlock> PlanningPointByBlocks { get { if ((this.serializing && (this._PlanningPointByBlocks.HasLoadedOrAssignedValues == false))) { return null; } return this._PlanningPointByBlocks; } set { this._PlanningPointByBlocks.Assign(value); } } [Association(Name="Division_Block", Storage="_Division", ThisKey="DivisionID", OtherKey="ID", IsForeignKey=true, DeleteOnNull=true, DeleteRule="CASCADE")] public Division Division { get { return this._Division.Entity; } set { Division previousValue = this._Division.Entity; if (((previousValue != value) || (this._Division.HasLoadedOrAssignedValue == false))) { this.SendPropertyChanging(); if ((previousValue != null)) { this._Division.Entity = null; previousValue.Blocks.Remove(this); } this._Division.Entity = value; if ((value != null)) { value.Blocks.Add(this); this._DivisionID = value.ID; } else { this._DivisionID = default(long); } this.SendPropertyChanged("Division"); } } } public event PropertyChangingEventHandler PropertyChanging; public event PropertyChangedEventHandler PropertyChanged; protected virtual void SendPropertyChanging() { if ((this.PropertyChanging != null)) { this.PropertyChanging(this, emptyChangingEventArgs); } } protected virtual void SendPropertyChanged(String propertyName) { if ((this.PropertyChanged != null)) { this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } private void attach_BlockByWorkstations(BlockByWorkstation entity) { this.SendPropertyChanging(); entity.Block = this; } private void detach_BlockByWorkstations(BlockByWorkstation entity) { this.SendPropertyChanging(); entity.Block = null; } private void attach_PlanningPointAppropriations(PlanningPointAppropriation entity) { this.SendPropertyChanging(); entity.Block = this; } private void detach_PlanningPointAppropriations(PlanningPointAppropriation entity) { this.SendPropertyChanging(); entity.Block = null; } private void attach_Neighbors(Neighbor entity) { this.SendPropertyChanging(); entity.FirstBlock = this; } private void detach_Neighbors(Neighbor entity) { this.SendPropertyChanging(); entity.FirstBlock = null; } private void attach_Neighbors1(Neighbor entity) { this.SendPropertyChanging(); entity.SecondBlock = this; } private void detach_Neighbors1(Neighbor entity) { this.SendPropertyChanging(); entity.SecondBlock = null; } private void attach_Tasks(Task entity) { this.SendPropertyChanging(); entity.Block = this; } private void detach_Tasks(Task entity) { this.SendPropertyChanging(); entity.Block = null; } private void attach_PlanningPointByBlocks(PlanningPointByBlock entity) { this.SendPropertyChanging(); entity.Block = this; } private void detach_PlanningPointByBlocks(PlanningPointByBlock entity) { this.SendPropertyChanging(); entity.Block = null; } private void Initialize() { this._BlockByWorkstations = new EntitySet<BlockByWorkstation>(new Action<BlockByWorkstation>(this.attach_BlockByWorkstations), new Action<BlockByWorkstation>(this.detach_BlockByWorkstations)); this._PlanningPointAppropriations = new EntitySet<PlanningPointAppropriation>(new Action<PlanningPointAppropriation>(this.attach_PlanningPointAppropriations), new Action<PlanningPointAppropriation>(this.detach_PlanningPointAppropriations)); this._Neighbors = new EntitySet<Neighbor>(new Action<Neighbor>(this.attach_Neighbors), new Action<Neighbor>(this.detach_Neighbors)); this._Neighbors1 = new EntitySet<Neighbor>(new Action<Neighbor>(this.attach_Neighbors1), new Action<Neighbor>(this.detach_Neighbors1)); this._Tasks = new EntitySet<Task>(new Action<Task>(this.attach_Tasks), new Action<Task>(this.detach_Tasks)); this._PlanningPointByBlocks = new EntitySet<PlanningPointByBlock>(new Action<PlanningPointByBlock>(this.attach_PlanningPointByBlocks), new Action<PlanningPointByBlock>(this.detach_PlanningPointByBlocks)); this._Division = default(EntityRef<Division>); OnCreated(); } [OnDeserializing()] [System.ComponentModel.EditorBrowsableAttribute(EditorBrowsableState.Never)] public void OnDeserializing(StreamingContext context) { this.Initialize(); } [OnSerializing()] [System.ComponentModel.EditorBrowsableAttribute(EditorBrowsableState.Never)] public void OnSerializing(StreamingContext context) { this.serializing = true; } [OnSerialized()] [System.ComponentModel.EditorBrowsableAttribute(EditorBrowsableState.Never)] public void OnSerialized(StreamingContext context) { this.serializing = false; } }

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  • Using Custom Validation with LINQ to SQL in an ASP.Net application

    - by nikolaosk
    A friend of mine is working in an ASP.Net application and using SQL Server as the backend. He also uses LINQ to SQL as his data access layer technology. I know that Entity framework is Microsoft's main data access technology. All the money and resources are available for the evolution of Entity Framework. If you want to read some interesting links regarding LINQ to SQL roadmap and future have a look at the following links. http://blogs.msdn.com/b/adonet/archive/2008/10/29/update-on-linq-to-sql-and...(read more)

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  • Role of an entity state in a component based system?

    - by Paul
    Component-based entity systems are all the rage these days; everyone seems to agree they are the way to go, but no one really has a definitive implementation of such a system. I was wondering, what role do entity states (walking-left, standing, jumping, etc) have in a CBS? Do they act like controllers (i.e. they handle events and change the entity's attributes based on those events)? What about cases where a state would, for example, require that the entity enters no-clip mode? Should, that state, when it enters, maybe set the CollisionComponent of the entity to a null pointer or something? (Then, on exit, the state should restore the entity's CollisionComponent to its previous state.) Also, I guess it's the current state's job to change the entity's state to something else, right?

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  • Entity Framework - Foreign key constraints not added for inherited entity

    - by Tri Q
    Hello, It appears to me that a strange phenomenon is occurring with inherited entities (TPT) in EF4. I have three entities. 1. Asset 2. Property 3. Activity Property is a derived-type of Asset. Property has many activities (many-to-many) When modeling this in my EDMX, everything seems fine until I try to insert a new Property into the database. If the property does not contain any Activity, it works, but all hell breaks loose when I add some new activities to the new Property. As it turns out after 2 days of crawling the web and fiddling around, I noticed that in the EF store (SSDL) some of the constraints between entities were not picked up during the update process. Property_Activity table which links properties and activities show only one constraint FK_Property_Activity_Activity but FK_Property_Activity_Property was missing. I knew this is an Entity Framework anomoly because when I switched the relationship in the database to: Asset <-- Asset_Activity <-- Activity After an update, all foreign key constraints are picked up and the save is successful, with or without activities in the new property. Is this intended or a bug in EF? How do I get around this problem? Should I abandon inheritance altogether?

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  • LINQ to Entity, using a SQL LIKE operator

    - by Mario
    I have a LINQ to ENTITY query that pulls from a table, but I need to be able to create a "fuzzy" type search. So I need to add a where clause that searches by lastname IF they add the criteria in the search box (Textbox, CAN be blank --- in which case it pulls EVERYTHING). Here is what I have so far: var query = from mem in context.Member orderby mem.LastName, mem.FirstName select new { FirstName = mem.FirstName, LastName = mem.LastName, }; That will pull everything out of the Member table that is in the Entity object. Then I have an addition to the logic: sLastName = formCollection["FuzzyLastName"].ToString(); if (!String.IsNullOrEmpty(sLastName)) query = query.Where(ln => ln.LastName.Contains(sLastName)); The problem is when the search button is pressed, nothing is returned (0 results). I have run the query against the SQL Server that I expect to happen here and it returns 6 results. This is the query I expect: SELECT mem.LastName, mem.FirstName FROM Members mem WHERE mem.LastName = 'xxx' (when xxx is entered into the textbox) Anyone see anything wrong with this?

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  • Entity Framework: insert with one-to-one reference

    - by bomortensen
    Hi 'overflow! I'm having a bit trouble inserting into a mssql database using Entity Framework. There's two tables that I want to insert into, where one of table 1s fields is a foreign key in table2. This is the code I have so far: Media media = null; foreach(POI p in poiList) { media = new Media() { Path = p.ImagePath, Title = p.Title }; if (media != null && !context.Media.Any(me => me.Title == p.ImageTitle)) { context.AddToMedia(media); context.SaveChanges(); } PointOfInterest poi = new PointOfInterest() { Altitude = 2000.0, ID = p.ID, Latitude = p.Latitude, Longitude = p.Longitude, LatitudeRoute = p.LatitudeRoute, LongitudeRoute = p.LongitudeRoute, Description = p.Description, Title = p.Title, DefaultImageID = media.ID, }; context.AddToPointOfInterest(poi); } context.SaveChanges(); The following gives me this error: An object with the same key already exists in the ObjectStateManagerAn object with the same key already exists in the ObjectStateManager I'm still learning how to use the entity framework, so I don't even know if this would be the right approach to insert into two referenced tables. Can anyone enlighten me on this? :) Any help would be greatly appreciated! Thanks!

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  • Entity Framework Custom Query Function

    - by Josh
    I have an Entity Framework 4.0 Entity Object called Revision w/ Nullable DateEffectiveFrom and DateEffectiveTo dates. I was wondering if there was a short-hand way of querying an object's RevisionHistory based on a particular QueryDate date instead of having to use the following query structure: var results = EntityObject.Revisions.Where(x => (x.DateEffectiveFrom == null && x.DateEffectiveTo == null) || (x.DateEffectiveFrom == null && x.DateEffectiveTo >= QueryDate) || (x.DateEffectiveFrom <= QueryDate && x.DateEffectiveTo == null) || (x.DateEffectiveFrom <= QueryDate && x.DateEffectiveTo >= QueryDate)); I've tried creating the following boolean function in the Revision class: partial class Revision { public bool IsEffectiveOn(DateTime date) { return (x.DateEffectiveFrom == null && x.DateEffectiveTo == null) || (x.DateEffectiveFrom == null && x.DateEffectiveTo >= date) || (x.DateEffectiveFrom <= date && x.DateEffectiveTo == null) || (x.DateEffectiveFrom <= date && x.DateEffectiveTo >= date)); } ... } And then updating the query to: var results = EntityObject.Revisions.Where(x => x.IsEffectiveOn(QueryDate)); but this obviously doesn't translate to SQL. Any ideas would be much appreciated.

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  • Auditing in Entity Framework.

    - by Gabriel Susai
    After going through Entity Framework I have a couple of questions on implementing auditing in Entity Framework. I want to store each column values that is created or updated to a different audit table. Rightnow I am calling SaveChanges(false) to save the records in the DB(still the changes in context is not reset). Then get the added | modified records and loop through the GetObjectStateEntries. But don't know how to get the values of the columns where their values are filled by stored proc. ie, createdate, modifieddate etc. Below is the sample code I am working on it. //Get the changed entires( ie, records) IEnumerable<ObjectStateEntry> changes = context.ObjectStateManager.GetObjectStateEntries(EntityState.Modified); //Iterate each ObjectStateEntry( for each record in the update/modified collection) foreach (ObjectStateEntry entry in changes) { //Iterate the columns in each record and get thier old and new value respectively foreach (var columnName in entry.GetModifiedProperties()) { string oldValue = entry.OriginalValues[columnName].ToString(); string newValue = entry.CurrentValues[columnName].ToString(); //Do Some Auditing by sending entityname, columnname, oldvalue, newvalue } } changes = context.ObjectStateManager.GetObjectStateEntries(EntityState.Added); foreach (ObjectStateEntry entry in changes) { if (entry.IsRelationship) continue; var columnNames = (from p in entry.EntitySet.ElementType.Members select p.Name).ToList(); foreach (var columnName in columnNames) { string newValue = entry.CurrentValues[columnName].ToString(); //Do Some Auditing by sending entityname, columnname, value } }

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  • Entity Framework and differences between Contains between SQL and objects using ToLower

    - by John Ptacek
    I have run into an "issue" I am not quite sure I understand with Entity Framework. I am using Entity Framework 4 and have tried to utilize a TDD approach. As a result, I recently implemented a search feature using a Repository pattern. For my test project, I am implementing my repository interface and have a set of "fake" object data I am using for test purposes. I ran into an issue trying to get the Contains clause to work for case invariant search. My code snippet for both my test and the repository class used against the database is as follows: if (!string.IsNullOrEmpty(Description)) { items = items.Where(r => r.Description.ToLower().Contains(Description.ToLower())); } However, when I ran my test cases the results where not populated if my case did not match the underlying data. I tried looking into what I thought was an issue for a while. To clear my mind, I went for a run and wondered if the same code with EF would work against a SQL back end database, since SQL will explicitly support the like command and it executed as I expected, using the same logic. I understand why EF against the database back end supports the Contains clause. However, I was surprised that my unit tests did not. Any ideas why other than the SQL server support of the like clause when I use objects I populate in a collection instead of against the database server? Thanks! John

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  • Understanding many to many relationships and Entity Framework

    - by Anders Svensson
    I'm trying to understand the Entity Framework, and I have a table "Users" and a table "Pages". These are related in a many-to-many relationship with a junction table "UserPages". First of all I'd like to know if I'm designing this relationship correctly using many-to-many: One user can visit multiple pages, and each page can be visited by multiple users..., so am I right in using many2many? Secondly, and more importantly, as I have understood m2m relationships, the User and Page tables should not repeat information. I.e. there should be only one record for each user and each page. But then in the entity framework, how am I able to add new visits to the same page for the same user? That is, I was thinking I could simply use the Count() method on the IEnumerable returned by a LINQ query to get the number of times a user has visited a certain page. But I see no way of doing that. In Linq to Sql I could access the junction table and add records there to reflect added visits to a certain page by a certain user, as many times as necessary. But in the EF I can't access the junction table. I can only go from User to a Pages collection and vice versa. I'm sure I'm misunderstanding relationships or something, but I just can't figure out how to model this. I could always have a Count column in the Page table, but as far as I have understood you're not supposed to design database tables like that, those values should be collected by queries... Please help me understand what I'm doing wrong...

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  • LINQ to Entity: using Contains in the "select" portion throws unexpected error

    - by Chu
    I've got a LINQ query going against an Entity Framework object. Here's a summary of the query: //a list of my allies List<int> allianceMembers = new List<int>() { 1,5,10 }; //query for fleets in my area, including any allies (and mark them as such) var fleets = from af in FleetSource select new Fleet { fleetID = af.fleetID, fleetName = af.fleetName, isAllied = (allianceMembers.Contains(af.userID) ? true : false) }; Basically, what I'm doing is getting a set of fleets. The allianceMembers list contains INTs of all users who are allied with me. I want to set isAllied = true if the fleet's owner is part of that list, and false otherwise. When I do this, I am seeing an exception: "LINQ to Entities does not recognize the method 'Boolean Contains(Int32)' method" I can understand getting this error if I had used the contains in the where portion of the query, but why would I get it in the select? By this point I would assume the query would have executed and returned the results. This little ditty of code does nothing to constrain my data at all. Any tips on how else I can accomplish what I need to with setting the isAllied flag? Thanks

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  • Seeding many to many tables with Entity Framework

    - by Doozer1979
    I have a meeting entity and a users entity which have a many to many relationship. I'm using Autopoco to create seed data for the Users and meetings How do i seed the UserMeetings linking table that is created by EntityFramework with seed data? The linking table has two fields in it; User_Id, and Meeting_ID. I'm looping through the list of users that autopoco creates and attaching a random number of meetings Here's what i've got so far. foreach (var user in userList) { var rand = new Random(); var amountOfMeetingsToAdd = rand.Next(1, 300); for (var i = 0; i <= amountOfMeetingsToAdd; i++) { var randomMeeting = rand.Next(1, MeetingRecords); //Error occurs on This line user.Meetings.Add(_meetings[randomMeeting]); } } I got an 'Object reference not set to an instance of an object.' even though the meeting record that i'm trying to attach does exist. For info all this is happening prior to me saving the context to the DB.

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  • Entity Framework one-to-one relationship mapping flattened in code

    - by Josh Close
    I have a table structure like so. Address: AddressId int not null primary key identity ...more columns AddressContinental: AddressId int not null primary key identity foreign key to pk of Address County State AddressInternational: AddressId int not null primary key identity foreign key to pk of Address ProvinceRegion I don't have control over schema, this is just the way it is. Now, what I want to do is have a single Address object. public class Address { public int AddressId { get; set; } public County County { get; set; } public State State { get; set } public ProvinceRegion { get; set; } } I want to have EF pull it out of the database as a single entity. When saving, I want to save the single entity and have EF know to split it into the three tables. How would I map this in EF 4.1 Code First? I've been searching around and haven't found anything that meets my case yet. UPDATE An address record will have a record in Address and one in either AddressContinental or AddressInternational, but not both.

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  • Entity Filter child without include

    - by Lic
    i'm a C# developer and i have a trouble with Entity Framework 5. I have mapped my database with Entity using the default code generation strategy. In particolar there are three classes: menus, submenus and submenuitems. The relationships about three classes are: one menu - to many submenus one submenu - to many submenuitems. All classes have a boolean attribute called "Active". Now, i want to filter all the Menus with the SubMenus active, and the SubMenus with the SubMenuItems active. To get this i've tried this: var tmp = _model.Menus.Where(m => m.Active) .Select => new { Menu = x, SubMenu = x.SubMenus.Where(sb => sb.Active) .Select(y => new { SubMenu = y, SubMenuItem = y.SubMenuItems.Where(sbi => sbi.Active) }) }) .Select(x => x.Menu).ToList(); But didn't work. Someone can help me? Thank you for your help!

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