MS SQL Server: Setting Default Values for Fields

Let's say you want certain fields to have their values set automatically when not explicitly passed. You can do this in the following ways:

• MS SQL Server defaults: configure default values, using fixed values or simple SQL functions, for columns in the table definition. E.g. an auto-incrementing id, a created_at timestamp, etc.
• Role based column presets: set up presets, using session variables or fixed values, that are applied when a row is created/updated with a particular user role. E.g. set a user_id field automatically from a session variable/authorization header.