Inheritance about jugglingdb

[1602]

What are your expectations due to inheritance? How it should be affected in persistence? In relational database we can create new table for inherited class with relation 'belongs to' or 'has one'. This table will only contain attributes for child class.

To be honest, I don't like this idea. Inheritance for persistent classes increases difficulty badly, IMHO.

Let's discuss.

[juggy]

My use case is what I described with Transaction.

• Transaction
  • FreeTransaction
  • PaypalTransaction

Exact same fields, but the behaviors change.

Maybe it can be done as a mixin or something, but the obvious way is to inherit.

[bentruyman]

I have a similar requirement. I have several schemas that look similar to the following:

Channel = {
  name: String,
  description: String,
  type: String,
  url: String,
  timeout: Number
}

ConfiguredChannel = {
  channel: Channel,
  timeout: Number
}

ChannelSet = {
  name: String,
  description: String,
  configuredChannels: [ConfiguredChannel]
}

ConfiguredChannelSet = {
  channelSet: ChannelSet,
  startTime: Number
}

Display = {
  name: String,
  configuredChannelSets: [ConfiguredChannelSet]
}

I'd like ConfiguredChannels to inherit their parent's attributes, like timeout. If no timeout is specified on the ConfiguredChannel, I'd use something like a pre-save hook to inherit that property from the parent. ChannelSets are comprised of ConfiguredChannels and a few other properties. Different Displays can reuse several predefined ConfiguredChannelSets but specify their startTime.

Maybe I'm modeling my data incorrectly — but this schema seems to "feel" right.

[1602]

I think this feature is not for schema definition internals, you can do some inheritance outside, like $.extend in jquery: define some "abstract" attributes set and reuse it for different model definitions.

[wbw20]

This issue should be implemented. Yeah its really hairy, but other popular ORMs have it (hibernate, active record). For instance, people might want their hierarchy to share an ID namespace. This is more than just using $.extend to save code. That being said, I realize its a huge complexity overhead