Direct Access to the Zotero SQLite Database
Zotero uses mozStorage, a database API backed by the SQLite database engine, offering the power of a relational database system within the Mozilla development environment. All system data and item metadata is stored in an SQLite database, zotero.sqlite, within the Zotero data directory.
However, external access to the SQLite database (including direct access via the mozStorage API) should be done only in a read-only manner. Modifying the database while Zotero is running can easily result in a corrupted database, as mozStorage caching breaks the normal file-locking in SQLite that allows for safe concurrent file access. And even if Firefox is shut down before accessing the file, modifying the database directly bypasses the data validation and referential integrity checks performed by Zotero and the Zotero server that are required for Zotero to function properly. Generally, the SQLite database should be viewed as an internal database that has the benefit of being externally readable for people who want to get the data out in other ways.
Also be aware that the SQLite database structure can change between Zotero releases.
Zotero Client Data Model
Each bibliographic record in Zotero has an “item type” (book, journal article, thesis, …), a set of fields (author, title, date, …), and field values. The selection of fields depends on the item type; for instance, a thesis has a “university” field which other items do not have.
Item types and fields, as well as translations into various languages, are defined in theZotero data schema. Zotero can be used in many languages, but you should always refer to item types and fields with their internal name as defined in data schema.
In theory, you can change and add item types and fields, but this will break Zotero sync and may make break many parts of Zotero functionality, such as item import and citation formatting. If you need to add additional information to your records, you should use the “Extra” field that is available for all item types.
In addition to the basic item types and fields, each item can have associated user data, including:
- a set of notes
- a set of attachments
- a set of tags
- a set of links to related items
Attachments (PDFs, snapshots, etc.) are stored inside the Zotero data directory, in separate subdirectories named after the ID of the item they belong to.
For a list of the internal names of fields, their English equivalents, and their CSL mappings, see the CSL/Zotero Metadata Field Index.