Hello,
I have the following schema that was designed before we were aware that
partitioning tables at the database server level is possible:
people: id, partition_id
profiles: id, person_id
data_points_x: id, profile_id
mappings_x: id, source_id, target_id
class Person < Sequel::Model
one_to_many :profiles
end
class Profile < Sequel::Model
many_to_one :person
one_to_many :data_points
end
class DataPoint < Sequel::Model
many_to_one :profile
one_through_one :source, join_table: mapping_x, left_key: target_id,
right_key: source_id, class: self
one_through_one :target, join_table: mapping_x, left_key: source_id,
right_key: target_id, class: self
end
Is there a way for the associated table partly be based on a column? For
example:
Profile[1].data_points
# SELECT people.partition_id FROM profiles JOIN people ON
profiles.person_id = patients.id -- returns '3', for example
# SELECT * FROM data_points_3 WHERE profile_id = 1; -- uses partition_id
from Person model for data_points_3
DataPoint instances should also know from which partition they are to be
able to correctly fetch its source and/or target:
DataPoint[1].source
# SELECT person.partition_id FROM data_points_3
# JOIN profiles ON data_points_3.profile_id = profiles.id
# JOIN patients ON patient_profiles.patient_id = patients.id
# WHERE data_points.id = 1;
# SELECT source_id FROM mappings_3 WHERE target_id = 1; -- assuming
returns 2
# SELECT * FROM data_points_3 WHERE id = 2;
The first SELECT query can also be omitted if the join_tables for the
:source and :target could be based from the derived table names for the
DataPoint instances i.e.:
^data_points_(?<partition_id>\d+)
"mappings_#{partition_id}"
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