entity-framework-5

问题 I am migrating an MVC 3 application from EF 4.3 to EF 5. I noticed that EF 5 expects a CreatedOn column in the __MigrationHistory table, which does not exist as the migrations were created by an older version. SELECT TOP (1) [c].[CreatedOn] AS [CreatedOn] FROM [dbo].[__MigrationHistory] AS [c] How do I resolve this issue without wiping my migration history? I am thinking of a query to infer the column's value from the migration name, which is in the following format: 201203111201542

问题 We have a static class library to deal with repeated multi-contextual tasks. Is it bad practice to create an EF db context as member of a static class? DB contexts are meant to be disposed of for a reason. Having them disposed frequently keeps the connection pool "flowing" and probably (here I'm speculating) assures that tables don't remain locked. So am I inviting trouble having a db context in a static class or am I overthinking this? 回答1: IMO this is definitally not something you want to

问题 I'm using .NET 4.0, MVC3, and EF5 with code first. My solution is split up into three projects, with the dependencies as indicated: Project.Web -> Project.BLL -> Project.DAL The Project.DAL layer contains my entity framework data context class and all my entities, but my startup project is Project.Web, so it contains my Web.config, connection strings, and the actual SQL compact database. I'm trying to enable migrations so I can add a new table to my EF model without wiping the existing data.

问题 I was using EF4 and a piece of code I found to get the MaxLength value from an entity like this: public static int? GetMaxLength(string entityTypeName, string columnName) { int? result = null; using (fooEntities context = new fooEntities()) { Type entType = Type.GetType(entityTypeName); var q = from meta in context.MetadataWorkspace.GetItems(DataSpace.CSpace) .Where(m => m.BuiltInTypeKind == BuiltInTypeKind.EntityType) from p in (meta as EntityType).Properties .Where(p => p.Name == columnName

问题 I was using EF4 and a piece of code I found to get the MaxLength value from an entity like this: public static int? GetMaxLength(string entityTypeName, string columnName) { int? result = null; using (fooEntities context = new fooEntities()) { Type entType = Type.GetType(entityTypeName); var q = from meta in context.MetadataWorkspace.GetItems(DataSpace.CSpace) .Where(m => m.BuiltInTypeKind == BuiltInTypeKind.EntityType) from p in (meta as EntityType).Properties .Where(p => p.Name == columnName

问题 I just enabled migrations in my project and added a few fields to UserProfile : [Table("UserProfile")] public class UserProfile { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int UserId { get; set; } public string UserName { get; set; } public string Email { get; set; } public string Description { get; set;} public DateTime? CreatedOn { get; set; } public DateTime? LastAccess { get; set; } } I Add-migration AddFieldsForUserProfile and it created: ... public

问题 I am working on winRT and entity framework (to SQL), the layer that communicates between them is WCF Service. In the entity framework I am using the Repository Pattern and I have the method: public IQueryable<User> GetBySearch(Expression<Func<User, bool>> search) { return this.Context.Users.Where(search); } Everything works fine, but when I add it to WCF [OperationContract] IQueryable<User> GetUserBySearch(Expression<Func<User, bool>> search); and: public IQueryable<User> GetUserBySearch

问题 I just upgraded my MVC4 project to .NET 4.5 and EF5 and started using VS2012. After realizing I needed to set-up auto-migrations in the Package Manager again I ran Enable-Migrations - EnableAutomaticMigrations and received the error No context type was found in the assembly 'MySolutionName'. Some Research has said that it has to do with EF5 not enabling prereleases. I ran Install-Package EntityFramework -IncludePrerelease but it said EF5 was already installed (which it was when I installed it

问题 I am getting this error when I try to use code first migrations. My context has a constructor with the connection name. public class VeraContext : DbContext, IDbContext { public VeraContext(string NameOrConnectionStringName = "VeraDB") : base(NameOrConnectionStringName) { } public IDbSet<User> Users { get; set; } public IDbSet<Product> Products { get; set; } public IDbSet<IntCat> IntCats { get; set; } } This connection name is injected with ninject when the project runs, I have also specified

问题 I just upgraded my MVC4 project to .NET 4.5 and EF5 and started using VS2012. After realizing I needed to set-up auto-migrations in the Package Manager again I ran Enable-Migrations - EnableAutomaticMigrations and received the error No context type was found in the assembly 'MySolutionName'. Some Research has said that it has to do with EF5 not enabling prereleases. I ran Install-Package EntityFramework -IncludePrerelease but it said EF5 was already installed (which it was when I installed it