Simplified Database Schema. A simplified version of the Ensembl variation database schema. Sequence variants are stored in the variation table shown in the top centre of the figure. A sequence variant is defined as having a source, flanking sequence and at least one allele. Structural variants have their own table. Connections to the Ensembl core database for sequencing information and genome annotations are highlighted. The full database schema is provided as a supplemental file and available at http://www.ensembl.org/info/docs/api/variation/variation_schema.html.