Systems, implementations, applications, and a query language for a tetrahedral data model for unstructured data are disclosed. The tetrahedral data model includes a vertex, four facets, and lines between the facets. The vertex represents a unique identifier for the underlying unstructured data. The four facets represent basic attributes, semantic features, low-level features, and raw data. The lines represent relationships between connected elements. The tetrahedral data model is implemented in the logical schema in an Unstructured data Base Management System (UDBMS), which stores the basic attributes and the semantic features in XML files, stores the low-level features and the raw data using a three-dimensional big table, and stores the associations in an adjacency matrix. A tetrahedral annotation module creating and populating tetrahedrons can be integrated into unstructured data processing apparatuses. An unstructured data query language provides comprehensive query operations for unstructured data represented by the tetrahedral data model in an UDBMS.