During bug reporting, The same bugs could be repeatedly reported. As a result, extra time could be spent on bug triaging and fixing. In order to reduce redundant effort, it is important to provide bug reporters with the ability to search for previously reported bugs efficiently and accurately. The existing bug tracking systems are using relatively simple ranking functions, which often produce unsatisfactory results. In this paper, we apply Ranking SVM, a Learning to Rank technique to construct a ranking model for accurate bug report search. Based on the search results, a topic model is used to cluster the bug reports into multiple facets. Each facet contains similar bug reports of the same topic. Users and testers can locate relevant bugs more efficiently through a simple query. We perform evaluations on more than 16,340 Eclipse and Mozilla bug reports. The evaluation results show that the proposed approach can achieve better search results than the existing search functions.

In a database application, for each attribute, a value is created initially via insertion. Then, the value can be referenced or updated via selection and updating respectively. Eventually, when the record is deleted, the values of the attributes are also deleted. These occurrences of events are associated with the states to constitute the attribute lifecycle. Our empirical studies discover that faults and incompleteness in database applications are highly associated with the attribute lifecycle. Consequently, we propose a novel approach to automatically extract the attribute lifecycle out of a database application from its source code through inter-procedural static program analysis. Data mining methods are applied to predict faults and incompleteness in database applications. Experiments on PHP systems give evidence to support applicability and accuracy of the proposed method.

Key and referential constraints are two main integrity constraints in database applications. These constraints can be automatically enforced by the Database Management System with their exception—violation from these constraints—handled by programmers. This paper proposes an approach to relieve the burden of programmers from mechanical coding for handling exceptions of these constraints violation by using program transformation. We first propose an extended abstract syntax tree to include SQL query semantics. Based on it, each code pattern that requires exception handling together with the exception handling code to be inserted is represented as a transformation rule. We provide two alternatives to handle the exceptions: one is to handle the exceptions in conjunction with the built-in enforcement feature in Database Management System; the other is handling them without using the feature provided in Database Management System. Hence, two types of transformation rules are provided accordingly. A tool GEHPHP (Generation of Exception Handling for PHP Systems) has been developed to implement the proposed approach. Experiments have also been conducted to evaluate the applicable of the approach.

Database is a major component of many software systems. This paper proposes a novel graph called the attribute dependency graph to reveal the dependencies between attributes in a database application and also the programs involved. The authors propose an approach to automatically extract the attribute dependency graph out of a database application from its source code through inter-procedural static program analysis. The extracted information is a straightforward indicator that benefits the maintenance process, particularly for impact analysis on the modifications in a database application. A tool has been developed to implement the proposed approach for PHP-based database applications. Case studies have also been conducted to demonstrate the use of our approach.

Key and referential constraints are the two main integrity constraints in database applications. These constraints can be enforced by the Database Management System automatically. Any violation from these constraints is handled by programmer's written code. This paper proposes an approach to relieve the burden of programmers from the mechanical coding for the exception handling of these constraints. In our approach, first SQL operations that may lead to constraint violations are identified. Then, based on SQL query patterns, the code for exception handling is generated accordingly and inserted into the program automatically. We provide two alternative ways to handle the exceptions: one is handling the exceptions without using the automated enforcement in Database Management System, the other is to handle it in conjunction with the DBMS enforcement. We have developed a tool, GEHPHP (Generation of Exception Handling for PHP Systems), and conducted experiments to verify the proposed approach.

Recent reports reveal that majority of the attacks to Web applications are input manipulation attacks. Among these attacks, SQL injection attack malicious input is submitted to manipulate the database in a way that was unintended by the applications' developers is one such attack. This paper proposes an approach for assisting to code verification process on the defense against SQL injection. The approach extracts all such defenses implemented in code. With the use of the proposed approach, developers, testers or auditors can then check the defenses extracted from code to verify their adequacy. We have evaluated the feasibility, effectiveness, and usefulness of the proposed approach by a set of open-source systems. Our experiment results showed that the proposed approach is effective in extracting all the possible defenses implemented/adopted by Web applications. We observed that the proposed approach would be useful in identifying the false positive cases resulting from other related approaches and auditing the code in order to fix the actual vulnerable cases.

Bug reporting is an uncoordinated process that is often the cause of redundant workload in triaging and fixing bugs due to many duplicated bug reports. Furthermore, quite often, same bugs are repeatedly reported as users or testers are unaware of whether they have been reported from the search query results. In order to reduce both the users and developers' efforts, the quality of search in a bug tracking system is crucial. However, all existing search functions in a bug tracking system produce results with undesired relevance and ranking. Hence, it is essential to provide an effective search function to any bug tracking system.

Database applications constitute a large portion of the software systems. This paper proposes a novel graph called attribute dependency graph to show the dependencies between attributes in a database application and also the programs involved. We propose an approach to automatically extract the attribute dependency graph through analyzing the source code of database applications. The extracted information can be used in the maintenance process particularly in the impact analysis upon modification of a database application. A tool has been developed to implement the proposed approach for PHP-based database applications. Case studies have also been conducted to demonstrate the use of our proposed approach.