Query in linguaggio naturale per il dominio della dieta mediterranea
Authors: Luca Anselma, Dario Ferrero, Alessandro Mazzei (Università di Torino, 2021)
Topic: Lexical and Semantic Resources and Analysis

Abstract
This paper presents an ongoing work for allowing users to ask questions in natural language to a database management system on the domain of repeats. The system translates questions from Italian language to SQL explaining an interlingua represented by a logical formalism such as relational calculus. There are two specific features of  this project: first, the use of relational calculus as semantic representation for interlingua translation; second, the role played by pragmatic information, that  is the Mediterranean diet domain implicitly encoded in the schema database.

Introduction
Access to large numbers of data by ordinary people is one of the many challenges faced for years to allow a smoother interaction between man and machine. The nature of human communication presents many aspects difficult to formalize through precise rules: ambiguity in the use of words and expressions, cultural and idiomatic differences, the reliance on implicit information given by the context.  This is also true in specific domains, such as the one that binds people to food  <cit.>.  For this purpose, the Natural Language Interfaces (NLIs) have been the subject of research for several years, systems able to interpret, model and execute a question formulated in Natural Language on some kind of basis of knowledge (bases of data, ontologies, etc.). The applications are therefore among the most diverse, from the simple search bars of a website, to the latest Voice Assistant and other services also web-based <cit.>.  The use of natural language has advantages and disadvantages compared to formal languages such as queries written in one of the database query languages. One of the advantages is the user's familiarity with natural language. One disadvantage is the extreme expressiveness of human language, which makes a total coverage of the vocabulary impossible and therefore possible interpretations of the meaning.        In this work we present an NLI to question a database in the domain of the Mediterranean diet. A question about this domain expressed in Italian will be analyzed through the use of a grammar feature-based context-free, represented by the relational calculation on tuple, and finally transformed into SQL through a recursive process based on the pragmatic of the application domain. A distinctive element of this project, compared to the classic examples of conversion based on the logic of the first order <cit.>, is the explicit use of relational calculation to represent the meaning of the sentence. Moreover, an important role is played by the pragmatic domain, which binds the language used in questions to the formalization of recipes, and which is codified in the database schema.

Conclusion
In this work were presented the first results of a project still in progress to interpret a question in natural language as an SQL question in the domain of the Mediterranean diet. The two main features of this project were the use of relational calculation on tuple to represent the meaning of the sentence (Section <ref>) and the use of domain specificities to then transform this representation into SQL (Section <ref>). In the future we intend to complete the questions contained in the proposed corpus and then integrate the prototype into a conversational agent on the domain of the management of a healthy diet. Considering the presence of indeterminateness in natural language, it might be interesting to provide support for extensions of the relational model that treat indeterminateness <cit.>.