Handle Fields with default values

[agenovese]

Looking for feedback, we need to decide how we want to handle/represent fields with default values.

Options:

• Try to extract the default value from the org.jooq.Table
  • Has the advantage that the client code can use the value of the field before the instance is persisted
  • Is pretty complex, and possibly wouldn't work in all circumstances. The default value is an SQL expression, not sure if it can depend on the other values in the object or even on values in other tables.
• Use an Option for the field, and have none indicate a desire to leave the field out
  • Simple, matches the behaviour of nullable fields
  • Hard to distinguish from a nullable field
  • not symmetrical, a fetched row with the default value doesn't look like a new row with the default value
• Use an Either[Unit, T] or similar, with the lhs representing a default value and the rhs representing a set value
  • Seems inelegant
  • no ability to use the default value before storage
  • not symmetrical, a fetched row with the default value doesn't look like a new row with the default value