Semantic interpretation of a database query language

In this paper, we will discuss a system that semantically interprets a formal database accessing language and generates natural language from this interpretation. In the past, the major way of communication between a user and a database was by means of a formal language. One such language is the SQL query language. Even though constructed as a user friendly language, SQL exemplifies the same difficulties for users as do other formal languages, namely a fairly rigid syntax, the necessity of variable binding, the lack of pronouns, and in the case of erroneous queries error messages that do not provide much insight. To alleviate some of the formal language problems, yet utilize the power of the formal language, we set out to build a natural language ‘umbrella’ for the SQL user. Our goal was not to build a natural language query system, but rather to use semantic knowledge and natural language for paraphrasing the formal language (SQL) and producing error messages as a feedback mechanism. In this way we build a genuine help facility, which would not only aid the user in dealing with SQL, but also trap erroneous queries.     

Two-dimensional specification of universal quantification in agraphical database query language

A technique is proposed for specifying universal quantification and existential quantification (combined with negation) in a two-dimensional (graphical) database query language. Unlike other approaches that provide set operators to simulate universal quantification, this technique allows a direct representation of universal quantification. Syntactic constructs for specifying universal and existential quantifications, two-dimensional translation of universal quantification to existential quantification (with negation), and translation of existentially quantified two-dimensional queries to relational queries are presented. The resulting relational queries can be processed directly by many existing database systems. The authors claim that this technique renders universal quantifications easy to understand. To substantiate this claim, they provide a simple, easy-to-follow guideline for constructing universally quantified queries     

Visual interaction using an iconic system

IBS (Icon Based System) is an experimental graphical query language based on icons. It demonstrates the capabilities of a workstation environment by integrating the aspects of database programming in one graphical setting. Namely, it allows direct manipulation of objects dealing with pictorial data as well as alphanumeric data. We point out the interaction techniques between users and database systems. Then we describe the design of IBS, illustrate its features, and show how queries are formulated in a medical context.     

Formalizing visual interaction with historical databases

Recent database applications are typically oriented towards a large set of non-expert users, and therefore, they need to be equipped with suitable interfaces facilitating the interaction with the system. Moreover, the incorporation of the time dimension in database systems is a desirable feature. Indeed, several temporal data models and the corresponding textual query languages have been proposed. However, there is a limited amount of research concerning the investigation of user-oriented languages for querying temporal databases. Our proposal addresses such a need. In particular, we propose a visual query environment, namely Temporal Visual Query Environment (TVQE) which provides an easier interaction of the user with temporal databases. The system adopts a diagrammatic representation of the database schema (including temporal classes and relationships) and a “graphical notebook” as interaction metaphor. In our approach, non-database experts are released from syntactical difficulties which are typical of textual languages, and they can easily express temporal queries by means of elementary graphical operations (e.g. click on a node label). Differently from many proposals in the field of visual query languages, the language underlying TVQE is provided with formal syntax and semantics. It is based on a minimal set of temporal graphical primitives (TGPs), which are defined on a Temporal Graph Model (TGM), with visual syntax and object-based semantics. In this paper we mainly concentrate on the formal aspects of TVQE, and provide some hints on the visual interaction mechanisms and implementation issues.     

Metaform: updatable form screens and their application to the use of office metaphors in query language instruction

A database interface language and system, called Metaform, which automatically generates multi-relational form screen interfaces for use by non-computer professionals has been developed. A form screen is a subset of the relational database, with a particular relation or combination of relations being represented. Through form screens, users can simultaneously query and update several relations in the database without having to know about its underlying structure. An overview of the Metaform system is presented and several examples of the use of the Metaform query language and update operators are described.

A series of 'usability' studies were conducted on a prototype of the Metaform system to examine the claims that the form concept aids computer-naive users in building complex database queries. These studies adopted the form screen concept to present six office paper work analogies to users to help them to understand the database retrieval concepts. The analogies of a file cabinet, a file folder, a stack of forms, a single form, a table of information on a form and a field of information were used in a two-staged training module.

At the end of each training sequence, users answered questions with the prototype and with paper and pencil which tapped their understanding of the database retrievals they were learning to perform. The results from these questionnaires were mixed. Users performed successful relational queries for simple retrievals and for those using existential quantifiers. They had difficulty with queries involving multiple steps and intermediate stages. Although users understood and used the analogies, they ran into difficulties with the ambiguities in the English statements of the queries, thus suggesting a need for another level of metaphors and/or problem representation tools not associated with the machine but with the user's comprehension of database retrieval problems.     

A visual query language for graphical interaction withschema-intensive databases

This paper presents a visual query language called VQL for interacting with an object-oriented schema-intensive data model. VQL allows convenient access to the various types of knowledge captured by the semantic model. It consists of a set of “graphical primitives” along with a combination grammar for creating graphical queries. The visual language is internally supported by a prolog-like predicate based query language. The formal grammar underlying the predicate based language is also presented. Apart from being able to create simple queries that can be specified in SQL or QBE, VQL can be used for making queries on any object-oriented data model including the generalization of the E-R model. VQL also handles complicated, indirect queries, specially those that require a reasoning system for query interpretation and response generation. Further, recursive queries on graph structures such as finding transitive closures of graphs may be easily specified. Perhaps the most powerful feature of VQL is its ability to provide high semantic expressibility (in being able to specify highly complex queries) while maintaining simplicity in the user's query formulation process. VQL is embedded in an object-oriented graphical database interaction environment that supports schema creation and manipulation in addition to database querying and updation. The prototype has been implemented in Smalltalk-80 running on a Sun 3/60 workstation. All the illustrations of visual interaction presented are taken from actual interaction sessions     

Metaform: updatable form screens and their application to the use of office metaphors in query language instruction

Abstract

A database interface language and system, called Metaform, which automatically generates multi-relational form screen interfaces for use by non-computer professionals has been developed. A form screen is a subset of the relational database, with a particular relation or combination of relations being represented. Through form screens, users can simultaneously query and update several relations in the database without having to know about its underlying structure. An overview of the Metaform system is presented and several examples of the use of the Metaform query language and update operators are described.

A series of ‘usability’ studies were conducted on a prototype of the Metaform system to examine the claims that the form concept aids computer-naive users in building complex database queries. These studies adopted the form screen concept to present six office paper work analogies to users to help them to understand the database retrieval concepts. The analogies of a file cabinet, a file folder, a stack of forms, a single form, a table of information on a form and a field of information were used in a two-staged training module.

At the end of each training sequence, users answered questions with the prototype and with paper and pencil which tapped their understanding of the database retrievals they were learning to perform. The results from these questionnaires were mixed. Users performed successful relational queries for simple retrievals and for those using existential quantifiers. They had difficulty with queries involving multiple steps and intermediate stages. Although users understood and used the analogies, they ran into difficulties with the ambiguities in the English statements of the queries, thus suggesting a need for another level of metaphors and/or problem representation tools not associated with the machine but with the user's comprehension of database retrieval problems.     

TQuery: a context-sensitive temporal query language.

Users of electronic medical databases request pertinent information by recasting their clinical questions into a formal database query language. Because the query language is the user's only access to the data, the query language must be powerful enough to enable users to express their data requirements. However, a competing need is for the query language to be restrictive enough so that queries can have unambiguous semantics and the query processor can generate correct answers. We describe a query language, called TQuery , that was designed specifically to formulate database queries that are dependent on temporal and contextual relationships. TQuery specifications express contextual constraints without the need to explicitly reference calendar dates. TQuery is the database query language used to retrieve patient data from an object-oriented electronic patient medical-record system called the temporal network (TNET). TNET and TQuery were developed to support the real-time temporal reasoning and representation needs of a LISP workstation-based medical expert system.     

No IFs,ANDs, or ORs: A study of database querying

The difficulty of expressing database queries was examined as a function of the language used. Two distinctly different query methods were investigated. One used a standard database query language, SQL, requiring users to express an English query using a formal syntax and appropriate combinations of boolean operators. The second used a newly designed Truth-table Exemplar-Based Interface (TEBI), which only required subjects to be able to choose examplars from a system-generated table representing a sample database. Through users' choices of critical exemplars, the system could distinguish between interpretations of an otherwise ambiguous English query. Performance was measured by number correct, time to complete queries, and confidence in query correctness. Individual difference analyses were done to examine the relationship between subjects' characteristics and ability to express database queries. Subjects' performance was observed to be both better, and more resistant to variability in age and levels of cognitive skills, when using TEBI than when using SQL to specify queries. Possible reasons for these differences are discussed.     

Building a database feedback system

Previous research has shown that user accuracy in database retrievals can be greatly improved by the provision of a conceptual level interface. However, there are still certain queries that are quite difficult. This calls for a feedback system which can provide feedback, regarding the system's interpretation of the query, to further enhance the user's accuracy, with the ultimate goal of 100% accuracy. This paper describes the design and implementation of a database feedback system on top of MERM, a Modified Entity-Relationship Model based DBMS. Specifically, the database feedback system performs the following functions:—it provides English translation of the query;—it shows syntax errors and suggests possible solutions to rephrase a syntactically wrong query; and—it shows likely semantic errors and suggests possible solutions.The results of a laboratory experiment which studies the effects of the database feedback system on user's performance is also reported in this paper.     

The Functional Data Model as the Basis for an Enriched Database Query Language

Conventional database languages rely on the user specifying what relations are to be used when evaluating a query. Consequently they preclude queries which involve searching for unspecified connections or associations in the database. In this paper we present Hydra, a functional language with all the facilities to define, update and query a database, which also enables users to carry out associational queries. Hydra uses a graph-based data model in which nodes represent values or entities and arcs the relationships between them. Associational facilities are made possible by the provision of built-in functions which find paths through the database graph. The mappings between sets of nodes in the database graph are represented as functions at the Hydra language level and it is as lists of such functions that associational results are returned. The use of a functional language is important since such languages allow functions to be returned as results; such an approach could not be adopted in a logic-based language which would not permit predicates to be returned as answers. Hydra also allows users to define general computational functions which are not considered to form part of the database. This use of two sets of functions achieves a computationally complete system which extends the query power of previous database systems without compromising their expressive or query power.     

A graphical user interface for Boolean query specification

Online information repositories commonly provide keyword search facilities through textual query languages based on Boolean logic. However, there is evidence to suggest that the syntactic demands of such languages can lead to user errors and adversely affect the time that it takes users to form queries. Users also face difficulties because of the conflict in semantics between AND and OR when used in Boolean logic and English language. Analysis of usage logs for the New Zealand Digital Library (NZDL) show that few Boolean queries contain more than three terms, use of the intersection operator dominates and that query refinement is common. We suggest that graphical query languages, in particular Venn-like diagrams, can alleviate the problems that users experience when forming Boolean expressions with textual languages. A study of the utility of Venn diagrams for query specification indicates that with little or no training users can interpret and form Venn-like diagrams in a consistent manner which accurately correspond to Boolean expressions. We describe VQuery, a Venn-diagram based user interface to the New Zealand Digital Library (NZDL). In a study which compared VQuery with a standard textual Boolean interface, users took significantly longer to form queries and produced more erroneous queries when using VQuery. We discuss the implications of these results and suggest directions for future work. Received: 15 December 1997 / Revised: June 1999     

Supporting efficient multimedia database exploration

Due to the fuzziness of query specification and media matching, multimedia retrieval is conducted by way of exploration. It is essential to provide feedback so that users can visualize query reformulation alternatives and database content distribution. Since media matching is an expensive task, another issue is how to efficiently support exploration so that the system is not overloaded by perpetual query reformulation. In this paper, we present a uniform framework to represent statistical information of both semantics and visual metadata for images in the databases. We propose the concept of query verification, which evaluates queries using statistics, and provides users with feedback, including the strictness and reformulation alternatives of each query condition as well as estimated numbers of matches. With query verification, the system increases the efficiency of the multimedia database exploration for both users and the system. Such statistical information is also utilized to support progressive query processing and query relaxation. Received: 9 June 1998/ Accepted: 21 July 2000 Published online: 4 May 2001     

Graphical presentation of boolean expressions in a database query language: design notes and an ergonomic evaluation

A new query language designed to improve ease-of-use and ease-of-learning for 'naive' users is presented. Its main interest is to avoid the explicit use of boolean operators for set operations by pointing on Venn diagrams. A human factors comparison with a more traditional design has been performed, using a query writing task. Results show that graphic representation of selected subsets allows less error-prone queries in a single relation database.     

数据修复与一致性查询处理研究

在数据库以及集成系统中通常存在违背数据约束的不一致查询问题。修复是解决该问题的主要手段之一,但目前还缺乏基于修复、约束与查询的统一模型研究。提出了基于删除元组修复、满足多种类型约束的一致性查询算法;阐明了具有简洁特性的约束定义与查询语句结构;构建了新的查询与修复系统模型,将关系实例集、非空的约束集、查询定义、修复方法等统一到模型中,以产生满足一致性约束要求的查询结果。所研究的方法、语言以及模型通用性强、适用面广,不局限于特定质量问题的修复与查询。     

数据库关键字查询技术研究

随着互联网技术与数据库技术的不断发展和相互结合,越来越多的用户需要访问在线数据库来获取各种信息,在该过程中,用户要对数据库中的数据进行查询。因此,用户就必需要掌握一定的结构化查询语言SQL,而且还要对数据库模式有一个认识和了解。但事实上,多数用户并不会使用结构化查询语言,也不了解数据库模式。所以,便产生了一个很自然的用户需求——数据库支持基于关键字的查询,文章主要就是对数据库支持基于关键字的查询进行简要的分析和探讨。     

Extending a Natural Language Interface with Geospatial Queries

In this installation of architectural perspectives, we describe an extension of a menu-based natural language interface (MBNLI) to support geospatial queries. Our extension makes it easier for application analysts and even inexperienced users to phrase complex queries without knowing the relational database query language SQL, database schemas (table structures), spatial operators, or spatial indexes.     

基于树状模型的复杂自然语言查询转SQL技术研究

自然语言查询转SQL(NL2SQL)是指将自然语言表达的查询文本自动转化成数据库系统可以理解并执行的结构化查询语言SQL表达式的技术.NL2SQL可以为普通用户提供数据库查询访问的自然交互界面,从而实现基于数据库的自然问答.复杂查询的NL2SQL是当前数据库学术界的研究热点,主流方法采用序列到序列(Seq2seq)的编解码方式对问题进行建模.然而,已有的工作大多基于英文场景,面向中文领域实际应用时,中文特殊的口语化表达导致复杂查询转化困难;此外,现有工作难以正确输出包含复杂计算表达式的查询子句.针对上述问题,提出一种树状模型取代序列表示,将复杂查询自顶向下分解为多叉树,树结点代表SQL的各组成元素,采用深度优先搜索来预测生成SQL语句.在Du SQL中文NL2SQL竞赛的两个官方测试集中,该方法分别取得了第1名和第2名的成绩,验证了其有效性.     

Kaleidoscope: a cooperative menu-guided query interface (SQLversion)

Kaleidoscope's approach is presented in the context of seeking improvement in the usability of interactive structured query language (SQL) interfaces. The system's cooperation is summarized as proposing valid query constituents step-by-step and providing lexical and semantic feedback immediately to users. To implement this intraquery guidance, the context-free grammar (CFG) is extended to capture the constraints useful for intraquery guidance, and the knowledge useful for pruning nonsensical queries and providing semantic feedback is articulated. For the SQL interface, this knowledge includes a strong domain concept, functional dependency, and integrity constraint rules, which can be acquired once in the database design step. The same types of knowledge are useful both for postquery cooperation and intraquery guidance. As SQL is supported bv virtually all database management system (DBMS) vendors, the approach presents a practical solution for casual database access