[SearchLight] - Can't edit primary key before saving about genieframeworkdemos HOT 2 CLOSED

@PGimenez
You could use this kind of convention where you use the same id for both but it's a bad idea, for multiple reasons:

a) it does not work in real life, with concurrent access (multiple users). When you have multiple users adding rows, the insert operations will run out of sync, becoming very difficult to "reserve" ids.

b) in terms of database design, it's not a good approach - by using foreign keys you can define relationships at database level to trigger cascade deletes and other operations.

c) same goes for what the users expect - most people will understand that there is a relationship by looking at the foreign keys.

d) SearchLight maps to the concept of primary key <-> foreign key with the Relationships API, allowing to set and manage relationships.

As such, we'd be showcasing a non-standard and not good approach to DB design, which is not ideal for a tutorial. Best thing would be to use the SearchLight Relationship API (which is not extensively documented though).

from genieframeworkdemos.

But if you run a quick initial iteration using this approach, it won't work through the ORM. You'll need to run a query, something like:

prediction.price = model([getfield(house, i) for i in 2:14])[1]
prediction.error = abs(prediction.price - house.MEDV)
prediction.timestamp = string(now())
@show prediction
save!(prediction)

SearchLight.query("
UPDATE predictions set id = $(house.id) where id = $(prediction.id)
")

# then retrieve prediction using the new id, if neede
prediction = findone(Prediction, id = house.id)

from genieframeworkdemos.