CONCLUSIONES Y RECOMENDACIONES
A.1. Conceptos Teórico de una Celda Electrolítica
Natural language (NL) systems for querying a database have shown technical feasibility and promise in terms of practical use, as evidenced by a large number of experimental systems [9, 87-89]. Some examples are shown in Table 2.4, which compares a restricted natural language with SQL.
Table 2.4: Research Conducted to Compare SQL and Natural Languages
1- Shneiderman
The aim of this study was to compare the use of Structured Query Language (SQL) and English in formulating valid database queries.
Subjects:
22 students participated in this study.Teaching / Training:
Students were enrolled in an undergraduate Cobolprogramming and information systems course.
Evaluation:
Three types of evaluation tests were employed in this study:- Comprehension questions involving three SEQUEL samples that students were to execute against the given database, and four English queries that had to be translated into SEQUEL.
- Situation Problem (SEQUEL) - Situation Problem (English)
Results:
The number of valid English and valid SQL queries had no significantdifferences. However, the number of invalid queries for English was significantly more than for SQL. In addition, natural language usage would be extremely
Researcher Reference Results
Shneiderman [8] Both languages were equal in valid query Vassiliou et al.[90] Natural language less verbose
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difficult without user knowledge of the application domain. There were no restrictions on the complexity of queries for natural language subjects. Under these circumstances, the SQL subjects might tend to write easy and simple questions to avoid syntax errors.
2-
Vassiliou et al.
The aim of the study is to compare performance between subjects using SQL and subjects using the prototype natural language system, USL (User Specialty Languages).
Subjects:
61 students were divided into three groups:1. Group 1 (10 students): USL with application training.
2. Group 2 (34 students): USL with application and language training. 3. Group 3 (17 students): SQL with application and language training.
Teaching / Training :
The three groups were trained for two hours in theapplication domain. Moreover, the second and third groups were trained in their respective languages (SQL or USL) for three and one half hours. Subjects in the first group were given a ten minute introduction to the interaction philosophy of USL.
Evaluation:
All groups were given the same paper-and-pencil test consisting offifteen questions. Students were asked to write the required queries to answer the questions in their assigned language. They were also asked to indicate on a five point scale the extent of their understanding of the question, how certain they were of a solution strategy, and how complex they believed the questions to be.
Results:
The reported results showed that there was no difference in subject’sperformance found on the basis of language type. In addition, the finding of a longer answer time for SQL subjects is consistent with the finding that SQL subjects had an average query length that was substantially larger than the USL
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average length. Moreover, the fact that USL subjects did not perform better than SQL subjects might be related to the time required for training to use natural language query systems which are quite demanding in restrictions
3- Turner et al.
The aim of this study was to test the performance differences between SQL and USL subjects.
Subjects:
8 paid students participated in this study.Teaching / Training:
Training consisted of a 1.5 hour classroom sessioncovering the application domain (date definitions, codes, structures, organization, key actors, etc.), and two 1.5 hour classroom instruction sessions in the respective language followed by a paper and pencil test. Both treatment groups (i.e. SQL and USL) were then given six 1.5 hour hands-on practice sessions with the system using requests modelled after actual user requests. An additional 1.5 hour classroom session was then given in each language followed by another six 1.5 hour practice sessions.
Evaluation:
Two tests were conducted as paper and pencil tests. The secondtest was constructed with questions that described problem situations in the application domain. Students were then asked to write the related queries that would generate the information needed to answer the question.
Results:
There was no significant difference in terms of performance, but thestandard deviation for the USL subject scores was almost twice that of the SQL subjects, suggesting more variation in USL subject performance. The results were based on data from only eight subjects, so one must be careful in interpreting the results.
Before interpreting the above reviewed studies, it is important to understand the nature of SQL and the natural language. SQL statements’ nature, syntax and content are different than other natural languages that novice express in their
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daily life. The rigid SQL syntax compared to the inexact and loose nature of NL, results in many students not being able to successfully write SQL as some of the above studies and others, such as Reisner [4, 57], reported as well.
Although many of the studies conclude that there is no significant difference between NL and SQL, it is possible to argue that NL may not be the best for use in executing a complex query or producing technical data. There are many limitations of natural language [66], such as:
- Users or learners may not be aware of the contents and semantics of the database. Therefore, they attempt to request information that is not available in the database.
- Using natural language without sufficient training allows the ambiguities of English syntax to pollute the query process.
- Many users can be aware of English syntax, but failed to understand the semantic of database.
- The efforts of creating and maintaining a natural language interface might be more than for a concise query language.
It is possible to argue, that computer science students are expecting to join the industry. Therefore, they should be able to process different type of query with level of complexity. Thus, teaching SQL within database course should be preferred among academics. One could think that introducing a restricted NL might be a good option to be introduced in level one or at school (i.e. before joining the university or at the foundation level in university). In other words, NL might be an alternative option for novice with no mathematical background, relational algebra, or computer concepts.
The next section investigates the influence of augmented use of query language and database structure.
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