The Full Picture: Federating, Replicating, and Caching Remote Data in CAP — Part 1

Part one of two, and the concepts half: terminology, what CAP already does, and what a project still has to write. It fixes a vocabulary — federation is the umbrella for making remote data part of your model, delegation forwards each request to the remote at query time, replication is a scheduled copy into the local database, and caching is an option on either rather than a third strategy — which collides with CAP's own, since what this series calls replication is what the CAP-level Data Federation guide calls federation. From the ground the Service Integration guide covers, it lists what is left to hand-write: cross-service $expand, navigation filters across the boundary, write forwarding, timeouts and retries, then scheduling, delta detection, backoff, a guard for two app instances sharing one schedule, idempotent writes, and knowing whether the last run succeeded. That list is why the edge to cds-data-federationcds-data-federationcds-pluginA data federation plugin for SAP CAP applications that declares delegation, caching and replication on a consumption view through CDS annotations, instead of hand-written handlers.independent, cap holds: the second half maps it onto @federation.delegate and @federation.replicate and says which package carries which part — annotations in cds-data-federationcds-data-federationcds-pluginA data federation plugin for SAP CAP applications that declares delegation, caching and replication on a consumption view through CDS annotations, instead of hand-written handlers.independent, cap, the scheduled engine in cds-data-pipelinecds-data-pipelinecds-pluginDeclarative scheduled pipelines between CAP services — each one a linear READ, MAP, WRITE from a single source to a single target, with tracking, retry, delta support and a management API.independent, cap, response caching through cds-cachingcds-cachingcds-pluginA caching plugin for CAP covering queries, requests, function results and remote service responses, through a read-through API or @cache annotations, with HCQL and MCP support.independent, cap — so it is the design rationale for the annotations, not the API reference. The gap list and the plugins answering it come from the same person who maintains them; cap-replication-democap-replication-demosampleReplication between systems with CAP.independent, cap and SAP's xtravels sample are cited as the hand-written form of the same work. Part 2 is announced as a walkthrough of a demo application and is not covered here.

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Mike ZaschkaMike ZaschkaPersonWrote this
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