seql.tree
Facilities to build trees of records based on a supplied
EQL field expression. This is exists because even though
LEFT JOIN queries build ad-hoc trees of data, a flat
(potentially unsorted!) list of records is what SQL will
give. The build function builds back the tree.
Facilities to build trees of records based on a supplied EQL field expression. This is exists because even though LEFT JOIN queries build ad-hoc trees of data, a flat (potentially unsorted!) list of records is what SQL will give. The `build` function builds back the tree.
buildclj
(build schema {:keys [fields]} records)The join query perfomed by seql.query/execute returns a flat list of entries,
potentially unsorted (this is database implementation specific)
recompose a tree of entities as specified in fields.
For instance let's assume the following list of records coming from a database query:
[{:account/id 0 :user/id 0}
{:account/id 0 :user/id 1}
{:account/id 2 :user/id 3}]
Calling build with a field definition of [:account/id {:account/users [:user/id]}]
will group the records together into:
[{:account/id 0 :account/users [{:user/id 0} {:user/id 1}]}
{:account/id 2 :account/users [{:user/id 3}]}]
Under the hood, the implementation keeps recursing between two functions:
walk-treewhich groups records togetheradd-relation-fnwhich builds a closure to add nested fields belonging to a relation
The join query perfomed by `seql.query/execute` returns a flat list of entries,
potentially unsorted (this is database implementation specific)
recompose a tree of entities as specified in fields.
For instance let's assume the following list of records coming from a database
query:
[{:account/id 0 :user/id 0}
{:account/id 0 :user/id 1}
{:account/id 2 :user/id 3}]
Calling `build` with a field definition of `[:account/id {:account/users [:user/id]}]`
will group the records together into:
[{:account/id 0 :account/users [{:user/id 0} {:user/id 1}]}
{:account/id 2 :account/users [{:user/id 3}]}]
Under the hood, the implementation keeps recursing between two functions:
- `walk-tree` which groups records together
- `add-relation-fn` which builds a closure to add nested fields belonging to a relationcljdoc is a website building & hosting documentation for Clojure/Script libraries
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