Overview

Data dictionaries are organized collections of schemas that define the structure, constraints, and relationships of data models. Overture's Data Dictionary Manager, Lectern, is designed to manage collections of data dictionaries and can be integrated into any data platform. Lectern typically works with Overture's tabular data submission service, Lyric, to ensure data quality and consistency throughout the submission workflow.

Key Features

• Schema Definition: Define schemas that specify the structure, constraints, and relationships of data elements
• Version Control: Track changes of data structures over time.
• Difference Computation: Compare versions to understand changes in data requirements.
• Schema Validation: Validate the structure and syntax of data dictionary schema against the Lectern base meta-schema.
• Integration: includes a RESTful API (Swagger) for integration with larger data management systems.

System Architecture

Lectern operates as a central Dictionary Schema repository, providing dictionary management and validation services through its RESTful API. The service maintains schemas in a database (mongoDb), tracking versions and relationships between different schema elements. In the Overture platform Lectern's schemas are consumed by Lyric, which stores and uses them to validate incoming tabular data submissions.

Repository Structure

The repository is organized with the following directory structure:

.
├── apps/
│   └── server
└── packages/
│   ├── client
|   ├── common
|   ├── dictionary
|   └── validation
└── scripts/

Click here to view the Lectern repository on GitHub

The modules in the monorepo are organized into three categories:

• apps/: Standalone processes meant to be run. These are published to ghcr.io as container images.
• packages/: Reusable packages shared between applications and other packages. Packages are published to NPM.
• scripts: Utility scripts for use within this repo.

Lectern Components

Each component serves a specific purpose within Lectern, providing functionality for server operations, client interactions, dictionary management, and data validation. Below is a detailed breakdown of the core components:

Component	Package Name	Path	Published Location	Description
Lectern Server	@overture-stack/lectern-server	apps/server/		Lectern Server web application.
Lectern Client	@overture-stack/lectern-client	packages/client		TypeScript Client to interact with Lectern Server and Lectern data dictionaries. This library provides a REST client to assist in fetching data from the Lectern server. It also exposes the functionality from the Lectern Validation library to use a Lectern data dictionary to validate data.
Lectern Dictionary		@overture-stack/lectern-dictionary		Dictionary meta-schema definition, includes TS types, and Zod schemas. This also exports all utilities for getting the diff of two dictionaries.
Lectern Validation	@overture-stack/lectern-validation	packages/validation/		Validate data using Lectern Dictionaries.