Databases are used to store data. Like other photograph management programs, digiKam uses the database to avoid data duplication, reduce data redundancy, enable fast search, and guarantee data integrity. Using a database also drastically reduces the cost of data entry, storage and retrieval. Additionally, any user can access the data using query language.

digiKam stores data (including albums, album roots, tags, thumbnails, face recognition data, image metadata, file paths, settings and others) in four databases:

  • Core database for all collection properties: hosts all albums, images and searches data.

  • Thumbnail database for compressed thumbnails: hosts image thumbs using wavelets compression images (PGF format).

  • Similarity database to store image fingerprints to enable fuzzy search.

  • Face database for storing face recognition metadata: hosts face histograms for face recognition.

Example of digiKam remote MySQL configuration hosted on a NAS from the local network

Details on database settings can be found in Database Setup section.

Migrating From Other Software

To populate the digiKam database from file properties managed by another software, it's recommended to write all metadata in XMP sidecar files for the best interoperability. digiKam cannot parse proprietary and closed source databases, while XMP sidecar is standardized and well documented.

Read Metadata Setup section to use XMP sidecar with digiKam. The Advanced panel offers profile management to handle special cases while importing and exporting metadata to and from 3rd-party software.

In a fresh installation of digiKam, you can create a new root collection at the directory where you store images managed by other software. The contents will be parsed and the database will be populated with the information found in the XMP sidecar files.

After the items are read (this can take a while), you will be able to see all tags, labels and comments in digiKam item properties.