Overview

The Open Database License (ODbL) is a legal instrument designed to govern the use, sharing and modification of database contents. It treats databases as works subject to copyright and related database rights, while setting conditions to keep data openly available. The ODbL is commonly described as a copyleft licence because it requires that certain freedoms granted with the original database be preserved in derivative databases.

Key features and obligations

At a practical level the ODbL permits copying, distributing and creating adaptations of a database, but normally attaches three main obligations that users should understand:

  • Attribution: Users of the licensed database must acknowledge the original source when using or redistributing the data.
  • Share-alike for adapted databases: If someone publicly shares a modified or derived database, the modified database must be made available under the same ODbL terms.
  • Licence for produced works: Works that use data from an ODbL database (for example maps, analyses or images) may be treated differently from the database itself; the licence distinguishes between database adaptations and "produced works" and sets conditions for each case.

History and adoption

The ODbL was published by Open Data Commons, a project associated with the Open Knowledge community, to provide a database-specific alternative to general content licences. One of the most visible adoptions occurred in 2012 when the OpenStreetMap project changed its data licence from a Creative Commons model to the ODbL, a move that highlighted the need for licences tailored to datasets rather than to creative works alone. The licence has since been used by a variety of open data projects and repositories that require share-alike protection for database content.

Use cases and importance

ODbL is used by governments, research groups, mapping projects and data aggregators who want to encourage reuse while preventing downstream enclosure of assembled datasets. It is particularly relevant where national or regional database rights exist, since it speaks directly to the legal status of collections of facts and records. Implementers should consider how attribution is presented and how derivative datasets will be published to remain compliant.

Distinctions and practical notes

The ODbL differs from general content licences such as those in the Creative Commons family because it focuses on datasets and their specific modes of reuse. For practical guidance, organisations often consult the text and explanatory materials provided by the licence stewarding bodies, including Open Data Commons and the Open Knowledge community. Readers can find introductions and official texts through developer and project resources, and by following links to authoritative pages (see Open Data Commons and discussions comparing ODbL with Creative Commons licences).

When planning to publish or reuse large datasets under the ODbL, legal review is recommended to clarify how the licence interacts with local database rights, contracts and downstream distribution channels.