Datomic Pull API by Stuart Holloway.
From the post:
Datomic‘s new Pull API is a declarative way to make hierarchical selections of information about entities. You supply a pattern to specify which attributes of the entity (and nested entities) you want to
pull, anddb.pullreturns amapfor each entity.Pull API vs. Entity API
The Pull API has two important advantages over the existing Entity API:
Pull uses a declarative, data-driven spec, whereas Entity encourages building results via code. Data-driven specs are easier to build, compose, transmit and store. Pull patterns are smaller than entity code that does the same job, and can be easier to understand and maintain.
Pull API results match standard collection interfaces (e.g. Java maps) in programming languages, where Entity results do not. This eliminates the need for an additional allocation/transformation step per entity.
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A sign that it is time to catch up on what has been happening with Datomic!