linkml-map

LinkML Map is a framework for specifying and executing declarative mappings between data models. At its core is the TransformationSpecification — a YAML-based language for describing how to map one data model to another, independent of serialization format or execution engine.

Features:

• YAML-based lightweight transformation syntax
• Python library for executing mappings on data files
• Tabular data support (TSV/CSV) with streaming for large datasets
• Experimental SQL compilation backend (DuckDB) for set-based transforms
• Derivation of target (implicit) schemas, allowing easy customization of data models (profiling)
• Simple YAML dictionaries for simple mappings
• Automatic unit conversion
• Use of subset of Python to specify complex mappings
• Visualizations of mappings
• Mappings are reversible (provided all expressions used are reversible)
• Multiple output formats (YAML, JSON, JSONL, TSV, CSV)

For full documentation see linkml.io/linkml-map/.

Status:

The transformation data model is not yet fully stable, and may be subject to change. Not all parts of the model are implemented in the reference Python framework.

Quickstart

Install:

pip install linkml-map
# or, in a uv-managed project: uv add linkml-map

When using uv, prefix CLI invocations with uv run (e.g. uv run linkml-map --help).

Run the included example (the example files live in this repo):

git clone https://github.com/linkml/linkml-map.git
cd linkml-map/tests/input/examples/personinfo_basic
linkml-map map-data --unrestricted-eval \
  -T transform/personinfo-to-agent.transform.yaml \
  -s source/personinfo.yaml \
  data/Container-001.yaml

See the Quick Start guide for the expected output and next steps.

More

• Tutorial Notebook
• Full docs
• Compliance Suite
• API Docs