Conceptual Query Language Research Articles

Development of a Conceptual Query Language: Adopting the User-Centered Methodology

The pervasiveness of end-user computing tools in the home and in workplaces, as well as the linkage of PCs into networks, have led to a convergence of end-user computing and corporate computing. As a result of this phenomenon, and because the productivity of end-users with these tools depends on how well suited the tools are to users, the issue of the suitability of computing tools for end-users is a valid concern for organizations. In the area of databases (DBs), the concern is that of ensuring the suitability of ad hoc querying and reporting tools for end-users. The significance of this concern lies in the realization that organizations and DB users are depending on more and more complex DBs, for example those being placed on the Web. DB researchers therefore argue for the adoption of the user-centered approach in developing these tools, to ensure suitability. The adoption of this approach in the development of the Conceptual Query Language (CQL) is reported in this paper. Also discussed is the series of experimental tests conducted to ascertain the impact of the approach on the usability of CQL. The test results suggest an improvement in user performance with and perception of CQL as a result of user participation in its development process.

An abbreviated concept-based query language and its exploratory evaluation

Research on the use of conceptual information in database queries has primarily focused on semantic query optimization. Studies on the important aspects of conceptual query formulation are currently not as extensive. Only a relatively small number of works exist in this area. The existing concept-based query languages are similar in the sense that they require the user to specify the entire query path in formulating a query. In this study, we present the Conceptual Query Language (CQL), which does not require entire query paths to be specified but only their terminal points. CQL is an abbreviated concept-based query language that allows for the conceptual abstraction of database queries and exploits the rich semantics of semantic data models to ease and facilitate query formulation. CQL was developed with the aim of providing typical end-users like secretaries and administrators an easy-to-use database query interface for querying and report generation. A CQL prototype has been implemented and currently runs as a front-end to an underlying relational DBMS. A statistical experiment conducted to probe end-users' reaction to using CQL vis-à-vis SQL as a database query language indicates that end-users perform better with CQL and have a better perception of it than of SQL. This paper discusses the design of CQL, the strategies for CQL query processing, and the comparative study between CQL and SQL.

Enriching the conceptual basis for query formulation through relationship semantics in databases

The rapid increase in end-user computing calls into question the suitability of existing database query languages (DBQLs). Because the typical DB end-user is not a DB specialist, it is essential that DBQLs use concepts that are as close as possible to those in the end-users’ cognitive mental model and adopt interface techniques that are suited to end-users’ abilities. Concept-based query languages are well suited for this. This realization has motivated further research in conceptual, or semantic, query approaches. However, the primary focus in this field has been on semantic query optimization, not on query formulation. In this study, we address ourselves to the problem of formulation of queries using concepts. We propose a concept-based query language, called the conceptual query language (CQL), which allows for the conceptual abstraction of database queries and exploits the rich semantics of data models to ease and facilitate query formulation. The CQL approach uses the relationship semantics of semantic data models to render transparent the technical complexities of existing DB query languages. Association semantics are also used to automatically construct query graphs and pseudo-natural language explanations of queries, and to generate SQL codes. A set theoretic formalism for conceptual queries is developed and used. This paper discusses the design of CQL, its expressive power, its implementation, and the strategies for CQL query processing. The implementation of a CQL prototype is briefly discussed in this paper. User experiments were carried out extensively and showed the advantage of CQL over alternative languages such as SQL.

A formal basis for an abbreviated concept-based query language

Concept-based query languages allow users to specify queries directly against conceptual schemas. The primary goal of their development is ease-of-use and user-friendliness. However, existing concept-based query languages require the end-user to explicitly specify query paths in totality, thereby rendering such systems not as easy to use and user-friendly as they could be. The conceptual query language (CQL) discussed in this paper also allows end-users to specify queries directly against the conceptual schemas of database applications, using concepts and constructs that are native to and exist on the schemas. Unlike other existing concept-based query languages, however, CQL queries are abbreviated, i.e., the entire path of a query does not have to be specified. CQL is, therefore, an abbreviated concept-based query language. CQL is developed with the aim of combining the ease-of-use and user-friendliness of concept-based languages with the power of formal languages. It does not require end-users to be familiar with the structure and organization of the application database, but only with the content. Therefore, it makes minimal demands on end-users' cognitive knowledge of database technology without sacrificing expressive power. In this paper, the formal semantics and the theoretical basis of CQL are presented. It is shown that, while CQL is easy to use and user-friendly, it is nonetheless more than first-order complete. A contribution of this study is the use of the semantic roles played by entities in their associations with other entities to support abbreviated conceptual queries. Although only mentioned here in passing, a prototype of CQL has been implemented as a front-end to a relational database manager.

Natural language querying of databases: an information extraction approach in the conceptual query language

Natural language (NL) interfaces for database (DB) query formulation have always been recognized as a much-needed enhancement for DB end-users. NL systems, however, have shortcomings that have led some DB researchers to question their practicality. The drawbacks stem primarily from their weak interpretative power. This weakness is, to a large extent, due to their inability to deal with the nuances in human use of natural language. Some studies, however, show that NL database systems are practical and useful in narrow domains like DB querying. One way of addressing the difficulty with NL database query languages (DBQLs) is to combine concept-based DBQL paradigms with NL approaches to enhance the overall ease-of-use of the query interface. In this study, the conceptual query language-with-natural language (CQL/NL) is proposed. CQL/NL uses information extraction methods to filter NL query statements for search predicates that are derived from constructs on conceptual schemas. In this way, it avoids the computational difficulty with full-fledged NL parsing. In the main, we draw on certain concepts in natural language processing and computational linguistics to develop CQL/NL.

Exploiting fact verbalisation in conceptual information modelling

An increasing number of approaches to conceptual information modelling use verbalisation techniques as an aid to derive a model for a given universe of discourse (the problem domain). The underlying assumption is that by elaborate verbalisation of samples of facts, taken from the universe of discourse, one can elicit a complete overview of the relevant concepts and their inter-relationships. These verbalisations also provide a means to validate the resulting model in terms of expressions familiar to users. This approach can be found in modern ER variations, Object-Role Modelling variations, as well as different Object-Oriented Modelling techniques. After the modelling process has ended, the fact verbalisations are hardly put to any further use. As we belief this to be unfortunate, this article is concerned with the exploitation of fact verbalisations after finishing the actual information system. The verbalisations are exploited in four directions. We consider their use for a conceptual query language, the verbalisation of instances, the description of the contents of a database, and for the verbalisation of queries in a computer supported query environment. To put everything in perspective, we also provide an example session with an envisioned tool for end-user query formulation that exploits the verbalisations.