Make factory name mandatory

[voievodin]

The problem

For each factory e.g.

{
  "v": "4.0",
  "name": "my-factory",
  "id": "i0rx6mlihjaayugt",
  "creator": {
    "name": "username",
    "created": 1465332525959,
    "userId": "user1234567"
  },
  "workspace": { }
}

the combination of factory.name + factory.creator.userId must be unique, so the factory
may be accepted as /<namespace>/<factory-name> where the namespace is the name of the user who is the creator of the factory.
Those factories which don't have name, cannot be accepted in the format described above.

Right now multiple factories with the same name may exist, as the unique constraint is missing.
In this case the first factory returned from factory service will be used.

The actual problem here is that the unique constraint like this requires partial unique index, which is not a common feature of database systems. It could look like this:

CREATE UNIQUE INDEX idx ON factory (user_id, name) WHERE (user_id IS NOT NULL)

While it works for PostgreSQL it doesn't for H2.

Proposed solution

Make factory name mandatory on database level + add a unique constraint on (user_id, name).

Each time factory service receives a factory without name it must set its name to some value e.g. factory id or generate a new factory name, so in this way clients are still not required to send factory name so everything works like before

For those factories in database that don't have name create a migration script that sets names equal to factory ids(or the values generated by the same principle as the values set by service) e.g:

factory_id	factory_name	user_id
factory123	null	user123
factory234	null	user123

⬇️ becomes ⬇️

factory_id	factory_name	user_id
factory123	factory123	user123
factory234	factory234	user123

For those factories in database that have duplicated name + user_id create a migration script that
leaves the very first factory with such a name as it is and modifies all the other factories in a way defined by the script from the previous statement. So the factories with such a name are accepted as they were(the first one) e.g:

factory_id	factory_name	user_id
factory123	example	user123
factory234	example	user123

⬇️ becomes ⬇️

factory_id	factory_name	user_id
factory123	example	user123
factory234	factory234	user123

[voievodin]

Check out factory_migration branch, it provides factory schema