Entity Framework - Invalid Column Name '*_ID"

I've narrowed this down to some issue between Code First and Database first EF, but I'm not sure how to fix it. I'll try to be as clear as I can, but I honestly am missing some of the understanding here myself. This is Entity Framework 4.4

I inherited a project where Entity Framework was used, but many of the actual files were deleted with no real way to go back. I re-added EF (Database first) and replicated a T4 setup that the project was built around. It generated code versions of all the database models and a DBContext code file.

If my connection string looks like a "normal" .NET connection string I get an error about an invalid column Name "ProcessState_ID" does not exist. ProcessState_ID is not in the code base at all, it is not in the EDMX file or anything. This appears to be some automatic EF conversion in the query.

When I make the connection string match the Entity Framework model it works fine.

Now in trying to match the previous code with Entity Framework I'd like to keep the "normal" .NET connection string.

So I have two questions here: 1. What is a good way to go from a normal connection string to an EF connection string in code? 2. Is there another fix here that I'm not seeing to stop the invalid column name error?

Check to see if you have any ICollections.

What I have figured out is when you have an ICollection that references a table and there is no column that it can figure out, it creates one for you to try to make the connection between the tables. This specifically happens with ICollection and has driven me "batty" trying to figure it out.

This is a late entry for those (like me) who didn't immediately understand the other 2 answers.

So...

EF is trying to map to the EXPECTED name from the PARENT TABLES KEY-REFERENCE...and since...the FOREIGN KEY name was "changed or shortened" in the databases CHILD TABLE relationship...you would get the message above.

(this fix may differ between versions of EF)

FOR ME THE FIX WAS:
ADDING the "ForeignKey" attribute to the model

public partial class Tour
{
    public Guid Id { get; set; }

    public Guid CategoryId { get; set; }

    [Required]
    [StringLength(200)]
    public string Name { get; set; }

    [StringLength(500)]
    public string Description { get; set; }

    [StringLength(50)]
    public string ShortName { get; set; }

    [StringLength(500)]
    public string TourUrl { get; set; }

    [StringLength(500)]
    public string ThumbnailUrl { get; set; }

    public bool IsActive { get; set; }

    [Required]
    [StringLength(720)]
    public string UpdatedBy { get; set; }

    [ForeignKey("CategoryId")]
    public virtual TourCategory TourCategory { get; set; }
}