C# – SubSonic 3 auto migrations in a live environment

In C# 5 and earlier, to give auto implemented properties an initial value, you have to do it in a constructor.

Since C# 6.0, you can specify initial value in-line. The syntax is:

public int X { get; set; } = x; // C# 6 or higher

DefaultValueAttribute is intended to be used by the VS designer (or any other consumer) to specify a default value, not an initial value. (Even if in designed object, initial value is the default value).

At compile time DefaultValueAttribute will not impact the generated IL and it will not be read to initialize the property to that value (see DefaultValue attribute is not working with my Auto Property).

Example of attributes that impact the IL are ThreadStaticAttribute, CallerMemberNameAttribute, ...

You can still use SubSonic 3 as a DAL and let SubSonic 2.2 generate the migrations for you. You just need sonic.exe and it's dependencies to execute the migration files.

To be more precise, I have folder Migrations in my DataLayer Project, that keeps all the migration Files but set the BuildAction to none. So I have Syntax Highlighting (but no error checking unless I set BuildAction back to compile) but the code does not mess my project.

You can keep them in an own project, of course. But I like it this way to have it under version control and be sure that my current DAL is matching my migration version.

In addition, I have named my config file migration.config (instead of app.config/web.config) and use this commandline to execute my migrations.

Command:           /path/to/sonic.exe  
Arguments:         migrate /config migration.config
Working Directory: $(SolutionDir)MyProject.Datalayer

Notice the /config switch to override the config file sonic.exe is looking for.