SqlException (0x80131904): Invalid object name 'dbo.Categories'

Question

I am getting the exception above when I run an application. The application is using asp.net mvc 3 / C#. I made an mdf file and added it under App_Data folder in Visual Web

Answer 1

Try using model builder class.It is the way to configure or explicitly define the mapping between table and model class.

In your entity/context class try adding this code

protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
       base.OnModelCreating(modelBuilder);
       modelBuilder.Entity<Category>().ToTable("Category");
    }

Its a method.Make sure ur using all the including statements.

Answer 2

What you really want to do to fix this is in you Context class you should have a method called OnModelCreating... make sure it has this:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
}

Answer 3

This usually means a simple configuration issue:

• perhaps there genuinely is no such table
• perhaps the table is there, but there is no dbo scheme (it might be in Fred.Categories)
• perhaps the db is case-sensitive (which is fine), and the table is actually dbo.CATEGORIES

Any of these will cause the above exception. In particular, you state:

My database contains 6 tables and one of them is Category.

Now to a machine, Category != Categories

Answer 4

Proven,tested & verified for table with name category or any SQL keywords named table use ToTable to instruct specific table name

 protected override void OnModelCreating(DbModelBuilder modelBuilder)
 {
     modelBuilder.Entity<category>().ToTable("category");
 }

Answer 5

Since this was still top search hit on the exception in April of 2018 and it led me to a solution, let me tack this on for a specific situation...

Our application is based on ABP and ABP.Zero, and we already have a pattern that fit Marc's answer. While I bet explicit mapping in the OnModelCreating method (a la Dhananjay's answer) would have worked perfectly, it seemed like ABP's mapping was working perfectly up to this point and I didn't want to break the pattern.

My solution was to add a table attribute to the entity class, and this settled EF's confusion.

using System;
using Abp.Domain.Entities;
using System.ComponentModel.DataAnnotations.Schema;

namespace Discovery.History
{

    [Table("HistoryRecords")]
    public class HistoryRecord : Entity<int>
    {
        public int ResearcherCount { get; set; }
        public DateTime DateSubmitted { get; set; }
        public string Comments { get; set; }
    }
}