Can I apply CC0 to a database or dataset?
Yes, you can apply CC0 to a database or dataset, provided you control the copyright and any sui generis database rights that apply. The one exact condition is that CC0 requires you to waive all copyright and related rights to the fullest extent permitted by law, without any license conditions attached. The decisive exception is that CC0 does not waive rights you do not hold, such as third-party copyright in individual data entries or rights governed by privacy, publicity, trademark, patent, or contract law. Before using the CC0 tool, verify that you own or have permission for every component of the database: structure, selection, and each item.
What CC0 Waives and What It Leaves Alone
What The Dedication Covers
CC0 is a public-domain dedication, not a license. It has three parts: a waiver of copyright and related rights, a fallback license where the waiver is not legally effective, and a non-assertion promise limited to remaining Copyright and Related Rights. For a database, this means you are giving up copyright in the original selection, coordination, and arrangement of data, as well as any sui generis database right that might exist under European law or similar regimes.
But CC0 cannot waive rights you do not own. If a dataset contains facts scraped from public records, the individual facts themselves are not copyrightable. Their compilation may be. If the dataset includes copyrighted images, text, or software code, those components are not covered by your CC0 dedication unless you own them too.
What Remains After The Dedication
The crucial distinction is between CC0, the Public Domain Mark (PDM), expired copyright, and licensed use. PDM is a label for material already free from known copyright restrictions worldwide. It changes no rights. Expired copyright depends on jurisdiction and the life of the author; you cannot rely on a single publication year. Licensed use, such as CC BY 4.0, grants specific permissions with conditions. CC0 is the only tool that aims to remove all copyright conditions entirely.
It does not guarantee clearance under privacy, publicity, trademark, patent or contract law. Rights held by other people remain, and CC0 expressly leaves the affirmer.s trademark and patent rights unaffected.
Copyright Versus Sui Generis Database Rights
Copyright protects the original expression in a database: the selection and arrangement of its contents. Sui generis database rights, which exist in the European Union and a few other jurisdictions, protect the investment of time and money in obtaining, verifying, and presenting the data. Version 4.0 of the Creative Commons licenses expressly addresses sui generis database rights. They are licensed along with copyright under the standard CC 4.0 tools. CC0 goes further: it waives both copyright and sui generis rights as far as the affirmer can. If you apply CC0 to a database you created, you are waiving your own copyright and your own database right. But if the database incorporates data from sources that retain their own sui generis rights, you cannot waive those.
This is where the failure case lives. A common mistake is to apply CC0 to a dataset compiled from public APIs or government records, assuming all rights are cleared. Public records are not copyrighted. Sui generis database rights may still protect the collective investment in the dataset if the original compiler spent substantial resources. If you repackage that data, you might infringe the original database right. The safe approach is to apply CC0 only to data you gathered yourself and for which you can document your own investment. For any third-party data, obtain a separate assurance, ideally a CC0 or public-domain dedication from the original source, before including it.
| Tool | What It Does | Who Can Apply It | Does It Cover Database Rights? |
|---|---|---|---|
| CC0 | Waives copyright and related rights; grants fallback license | Only the rights holder or authorised agent | Yes, includes sui generis database rights |
| Public Domain Mark (PDM) | Labels material already in the public domain | Anyone, but only appropriate if work is free of known restrictions worldwide | No, changes no rights |
| CC BY 4.0 | Licenses copyright with attribution condition | Only the rights holder | Yes, version 4.0 expressly covers sui generis database rights |
| Expired Copyright | Work is no longer protected by copyright | No one applies it; status is determined by law | Depends on jurisdiction; sui generis rights may persist independently |
| No License (All Rights Reserved) | Copyright and database rights remain fully enforced | Implicitly the rights holder | Yes, all rights are retained |
The Practical Steps to Apply CC0 to a Database
Attaching The Notice Correctly
Applying CC0 is not a legal process with a registry. Creative Commons does not register works, verify ownership, or give legal advice. You attach a notice to your database that states you are dedicating it to the public domain using the CC0 tool. The official chooser at creativecommons.org generates a standardised notice. Include the deed URL (creativecommons.org/publicdomain/zero/1.0/) and the legal code URL (same URL plus /legalcode). In the notice, identify yourself as the affirmer, name the database, and indicate that you are waiving all copyright and related rights to the fullest extent permitted.
Placement And Contract Traps
Where this goes wrong is in the details. If your database has a complex structure with multiple tables or a user interface, ensure the notice is visible on the download page, inside the data file as a header comment or metadata field, and in any documentation. Do not apply CC0 if the database is subject to a contract that restricts reuse, even if you own the copyright. A contract term can override a public-domain dedication. A dataset obtained under a fee-based subscription that prohibits redistribution cannot be released under CC0 without breaching that contract. Check the terms of any data source before dedicating.
What Most Often Goes Wrong With CC0 and Databases
The single most common mistake is applying CC0 to a database built from multiple sources without verifying rights in each component. A researcher scrapes public data, adds curated annotations, and releases the combined dataset under CC0. The public data may be free. The annotations are copyrighted. The original compiler may hold sui generis database rights. The researcher has waived only their own rights, not the third-party rights. The result is that users who rely on the CC0 dedication may be infringing, and the researcher may face a takedown request or legal action.
The practical fix is straightforward. Before applying CC0, document the provenance of every row, every column, every annotation. If any component came from a source that requires attribution or restricts reuse, do not include it unless you have explicit permission to waive those terms. If the database is entirely your own creation, original survey data, experimental results, or your own measurements, CC0 is safe. For anything else, treat the dedication as incomplete. The one sentence that sums up the decisive failure: applying CC0 to a database that contains third-party data without permission does not make that third-party data free, and it can expose both you and your reusers to liability.
Common Questions
Can I apply CC0 to a database that contains third-party data?
Only if you have permission from each third-party rights holder to waive their rights. CC0 waives only the rights you control. If the database includes copyrighted text, images, or data from other sources, those components remain protected.
Does CC0 waive sui generis database rights in all countries?
No. CC0 aims to waive them to the fullest extent permitted by law. But the existence and scope of sui generis rights vary by jurisdiction. The European Union recognises them; many other countries do not. CC0 cannot waive a right that does not exist, and it cannot waive a right you do not hold.
What is the difference between CC0 and the Public Domain Mark for a dataset?
CC0 is a tool you apply to waive your own rights. PDM is a label for material you believe is already free of known copyright restrictions worldwide. PDM changes no rights. If you created the dataset, use CC0. If you are sharing a dataset that is already in the public domain, PDM is appropriate.
If I apply CC0, can I later change my mind and restrict use?
No. CC0 is irrevocable. Once you dedicate a database to the public domain, you cannot withdraw the dedication from copies already distributed. You can stop distributing new copies under any terms, but existing copies remain under CC0. This is the same rule as with Creative Commons licenses.
Does CC0 require attribution?
No. CC0 has no conditions. Users are not required to credit you. However, citation and research integrity norms may still make credit proper. If you need attribution, use CC BY 4.0 instead of CC0. Do not attach CC0 and then demand credit; that contradicts the tool's purpose.
Can I use CC0 for a database that includes software code?
Creative Commons recommends against using any CC tool for software code. Use a recognised free/open-source software license, such as the GNU General Public License or MIT License, which are designed for source code, patents, and distribution. Non-code assets in the same project, such as documentation, may carry a separate CC license if clearly marked.
What happens if someone uses my CC0 database in a way I do not like?
CC0 removes all copyright and related-right conditions. You cannot object on copyright grounds. However, non-copyright rights, privacy, publicity, trademark, patent, contract, or cultural heritage laws, may still restrict the use. If the use violates those, local legal advice is needed. Creative Commons does not enforce individual dedications.