Science Data Model Schemas

This repository stores schema definitions for user-facing data products (the Science Data Model, or SDM). These schema definitions are YAML files that are designed to be read with felis (https://github.com/lsst-dm/felis), which can create derived schema formats from the YAML definitions (e.g., SQL CREATE TABLE statements, or IVOA TAP_SCHEMA table contents.) These YAML schema definitions serve as the "source of truth" for other downstream usage, including verification of the catalog outputs from Rubin Observatory science pipelines.

The schemas in this repository serve several different purposes:

• yml/imsim.yaml describes the outputs of the pipelines for LSSTCam-imSim. It is used to generate the data preview schemas, which are fixed at the time of their release, while this one will continue to evolve. This schema is used by ci_imsim, which verifies that the schema of the pipeline output files agree with the contents of this file.

• The various dp0X schemas represent what is actively being served by the various data previews. These are created from yml/imsim.yaml at a specific point in time.

• yml/apdb.yaml describes the schema used in the Alert Production Database (APDB). This schema reflects the current schema that is used for Alert Production with ap_pipe. It is also used in nightly ap_verify runs for continuous integration. Previous processing runs may differ from the current schema. The user-queryable Prompt Products Database (PPDB) is expected to have a very similar schema to the APDB.

• yml/hsc.yaml describes the outputs of the latest data release production pipelines for HyperSuprimeCam. This schema is used by ci_hsc, which verifies that the schema of the pipeline output files agree with the contents of this file.

Release assets

Each release of sdm_schemas includes the following additional release assets, generated automatically via GitHub Actions when a new tag is created.

• datalink-columns.zip contains a set of YAML files with a restricted subset of the Felis schema. Currently, they identify the principal and minimal columns for a subset of the tables defined by the schema in this repository. Principal columns are those for which the principal flag is set in the TAP schema, and have the meaning defined in the IVOA TAP specification. Minimal columns are still experimental and in flux. These files are intended for use with the datalinker service of a Rubin Science Platform depoyment.

• datalink-snippets.zip contains a JSON manifest and a set of XML files that define VOTables following the IVOA DataLink specification. This release asset is intended for use with the TAP service of a Rubin Science Platform deployment and is used to add DataLink records to the responses from a TAP query. Those DataLink records, in turn, provide links to operations that a client may wish to perform on those results, such as closely-related TAP queries.