Asp.Net MVC Adding A Table - asp.net

Question

I have seen several tutorials and examples about starting with a new database, and about adding columns and fields to models/existing tables. I need to add 2 new tables to a production database without messing with the existing tables.
I tried creating 2 new models and then using add-migration like I did with fields for existing models but this did not work, it created an empty migration with an empty Up and empty Down field.
I'm iffy to do anything because I am going to have to do this to a production DB after I get it working on test DB.
Bascially:
public class ChatModel {
public int Id { get; set; }
public string CaseNumber { get; set; }
public string AgentName { get; set; }
public string CustomerEmail { get; set; }
public DateTime Time { get; set; }
public string Transcript { get; set; }
public virtual SurveyModel Survey { get; set; }
}
and
public class SurveyModel {
[ForeignKey("ChatModel")]
public int ChatId { get; set; }
public int Id { get; set; }
public string Question1 { get; set; }
public string Question2 { get; set; }
...
public virtual ChatModel Survey { get; set; }
}

Answer 1

First Point : Why Up and down functions are empty?
Check your Migrations directory inside your project. It contains all the classes for migration which get created in Timestamp_MigrationName format. You might want to check few most recently created files in that directory to see if your recent model related changes (two new tables) are already present in any one of them. Possibly because of execution of the Add-Migration command more than once your new migration files which are getting created are coming empty as EF is not detecting any new model changes since you ran Update-Database command last time.
Second Point : How to update the production database with latest Model changes which has two new tables
Updating the production database is a crucial thing. I don't think you are planning to update your production database directly from your development environment by running Add-Migration and Update-Database command. It is highly risky and never recommended. Using the pair of "Add-Migration" and "Update-Database" commands is the right way if you intend to update your development/local database. For updating your production database here are the set of commands which you should be firing:
Remove the _MigrationName.cs file from Migration folders under your project which contains the changes related to your two new tables. This step is required only because you are getting empty Up and Down functions whenever you are running Add-Migration command. Otherwise this step would not have been required if everything was smooth.
Run the command Add-Migration AddNewModels on package manager console.
Run the command Update-Database -Script on package manager console. This step creates a .sql extension file which will contain all the t-sql queries (DDL statements) required to make all the new schema changes. Visual Studio opens the newly created *.sql file automatically in front of you for a quick review and saving at a path of your choice.
Run the command Update-Database to commit the changes to your local/development database. This step is required else you will not be able to start new migrations if you desire.
Now hand-over the scripts file which got created in step # 3 above to your production DBA and you are good to go. You production database upgrade will happen seamlessly without any errors and your application will be compatible with the changes.