Intra-data source Relationships
This is the official documentation of the agent_ruby
Ruby agent.
We've seen that when building data sources, collections must fulfill the contract they defined when declaring their capabilities.
The same is also true for Intra-data source relationships which are declared on the structure of a collection: declared relations must be handled when processing filters
, projection
, and aggregations
.
In practice
one-to-many
and many-to-many
relationships do not require additional work: Forest Admin will automatically call the destination collection with a valid filter.
On the other hand, many-to-one
and one-to-one
relationships require the implementer to make all fields from the target collection available on the source collection (under a prefix).
Example
If a structure declaration contains the following statement
module App
module Collections
class Movie < ForestAdminDatasourceToolkit::Collection
include ForestAdminDatasourceToolkit::Schema
include ForestAdminDatasourceToolkit::Components::Query:: ConditionTree
def initialize(datasource)
super(datasource, 'Movie')
# [...]
add_field('director', ManyToOneSchema.new(
foreign_key: 'director_id',
foreign_key_target: 'id',
foreign_collection: 'People'
))
end
end
end
end
Then the collection must accept references to fields from the people
collection under the director
prefix in all method parameters.
datasource.collection('Movie').list(
caller,
ForestAdminDatasourceToolkit::Components::Query::Filter.new(
condition_tree: ForestAdminDatasourceToolkit::Components::Query::ConditionTree::ConditionTreeBranch.new(
aggregator: 'and',
conditions: [
ForestAdminDatasourceToolkit::Components::Query::ConditionTree::ConditionTreeLeaf.new(
field: 'title',
operator: 'Equal',
value: 'E.T.'
),
ForestAdminDatasourceToolkit::Components::Query::ConditionTree::ConditionTreeLeaf.new(
field: 'director:firstName',
operator: 'Equal',
value: 'Steven'
),
],
),
sort: ForestAdminDatasourceToolkit::Components::Query::Sort.new(
[
{
field: 'director:birthDate',
ascending: true
}
]
)
)
)
should return
{
"id": 34,
"title": "E.T",
"director": { "firstName": "Steven", "lastName": "Spielberg" }
}
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