The original database. **Proba DB [5] contains data from 1,174 scientific articles (Bibliography table) about 49,285 samples of igneous rocks (Measurements**
table). Samples are collected all over the globe, which is reflected in the Localities, llocal, lglobal and lgroup tables. The samples are assigned a rock type
(Rocks table), a genesis type (Errupttypes table), age (ages table), and, which is the main thing, weight percentage (Concentrations table) of chemical substances and isotopes (list in the Elements table).

This brief description alone already shows that table and column identifiers can only approximately match the terms used by petrologists to exchange sample data. The transition to CNL also solves the problem of converting the data saved in RDB to knowledge in a form directly understandable to experts in the subject domain.

CNL sentences. **List 1 includes examples of all types of CNL sentence required**
to present all facts contained in the Proba DB. Local (internal) proper names required to name various objects within the knowledge base are used in the sentences. So, PUB5633 is the name of article number 5633 (from bibliography.id)
in the DB. SAM32994 is the name of sample number 32994 (from measurements.id) in the DB, etc. Words are connected by letter " **" in compound terms.**
The text also contains well-known global proper names, for example, Iceland, Atlantic **Ocean.**
List 1. Example of CNL sentences.

PUB5633 is a publication. A title of PUB5633 is "A CONTRIBUTION TO THE GEOLOGY OF THE K...".

SAM32994 is a sample. SAM32994 is a rhyolite. PUB5633 describes SAM32994. PLC32994 is a place. PLC32994 is a part of Iceland.

A gathering_place of SAM32994 is PLC32994. SUB469812 is a substance. SAM32994 includes SUB469812. WPC469812 is a weight_percent. A value of WPC469812 is 73.95. A component of WPC469812 is SUB469812.

The sentence structure is very simple. A very limited natural language is actually required to record all facts contained in a RDB if RDB is normalized. But RDB Proba is normalized not everywhere. Completing normalization is one of the tasks of reorganizing a DB to enable automatic conversion to **knowledge.**
Rules of mapping the RDB content to CNL have been developed. These rules are the specification for SQL-scripts dumping RDB to CNL text [15].

OWL ontology: getting and analysis. All generated sentences are ACE language [3] sentences, and are selected so that a concrete APE compiler 2**could**
compile them to OWL. A portion of the knowledge contained in each article is 2 **Attempto Parsing Engine** http://attempto.ifi.uzh.ch/site/tools/