Jean-Luc Hainaut

Contribution to a theory of database reverse engineering

Both a general framework and specific techniques for file and database reverse engineering (recovering its conceptual schema) are proposed. The framework relies on a process/product model that matches formal as well as empirical design procedures. Based on the analysis of database design processes, two major phases are defined, i.e., data structure extraction and data structure conceptualization. For each of them, a set of activities is proposed. Most of these activities can be described as transformation and integration of specifications.<<ETX>>

Database Design Recovery

The design of a software component, such as a database, is the trace of all the processes, products and reasonings that have led to the production of this artifact. Such a document is the very basis of system maintenance and evolution processes. Unfortunately, it does not exist in most situations. The paper describes how the design of a database or of a collection of files can be recovered through reverse engineering techniques. Recording the reverse engineering activities provides a history of this process. By normalizing and reversing this history, then by conforming it according to a reference design methodology, one can obtain a tentative design of the source database. The paper describes the baselines of the approach, such as a wide spectrum specification model, semantics-preserving transformational techniques, and a design process model. It describes a general procedure to build a possible DB design, then states the requirements for CASE support, and describes DB-MAIN, a prototype CASE tool which includes a history processor. Finally it illustrates the proposals through an example.

Program Understanding in Databases Reverse Engineering

The main argument of the paper is that database understanding (or reverse engineering) requires sophisticated program understanding techniques, and conversely. Database reverse engineering (DBRE) can be carried out following a generic methodology, one of the phases of which consists in eliciting all the implicit and untranslated data structures and constraints. Evidences of these hidden constructs can be found by analysing how the programs use and update the data. Hence the need for program analysis techniques such as searching for cliches, dependency analysis, program slicing and synthetic views. The paper explains how these techniques contribute to DBRE, and describes DB-MAIN, a programmable and extensible CASE environment that supports DBRE through program understanding techniques.

Database reverse engineering: from requirements to CARE tools

This paper analyzes the requirements that CASE tools should meet for effective database reverse engineering (DBRE), and proposes a general architecture for data-centered applications reverse engineering CASE environments. First, the paper describes a generic DBMS-independent DBRE methodology, then it analyzes the main characteristics of DBRE activities in order to collect a set of desirable requirements. Finally, it describes DB-MAIN, an operational CASE tool developed according to these requirements. The main features of this tool that are described in this paper are its unique generic specification model, its repository, its transformation toolkit, its user interface, the text processors, the assistants, the methodological control and its functional extensibility. Finally, the paper describes five real-world projects in which the methodology and the CASE tool were applied.

Strategies for data reengineering

This paper describes and analyzes a series of strategies to migrate data-intensive applications from a legacy data management system to a modern DMS. Considering two ways to migrate the data and three ways to propagate the corresponding perturbation to the program code, the paper identifies six reference strategies that provide different levels of quality and induce different costs. Three of them are discussed in detail and illustrated by the conversion of COBOL files into a SQL database.

Requirements for information system reverse engineering support

This paper proposes a general architecture for information systems (or data-centered applications) reverse engineering CASE environments. Recovering the specifications of such applications requires recovering first those of their data, i.e. database reverse engineering (DBRE). First, the paper describes a generic DMS-independent DBRE methodology, then it analyses the main characteristics of DBRE activities in order to collect a set of minimum or desired requirements. Finally, it describes the main features of an operational CASE tool developed according to these requirements. This study and these developments are being carried out as part of the DB-MAIN and DB-PROCESS projects.

Transformation-based Database Reverse Engineering

The paper presents a DBMS-independent database reverse engineering (DBRE) methodology based on a generic process model and on transformation techniques. DBRE is proposed as a two-phase process consisting in recovering the DBMS-dependent data structures (data structure extraction) then in recovering their semantics (data structure conceptualization). The second phase, that is strongly linked with the logical design phase of current database design methodologies, can be performed by application of a selected set of standard schema restructuring techniques, or schema transformations. The paper illustrates the methodology by applying it to various DBRE processes : removing optimization structures, untransfating Relational, COBOL, CODASYL, TOTAL/IMAGE and IMS database as well as file structures, and finally conceptual normalization.

Specification preservation in schema transformations—application to semantics and statistics

Abstract Software design can be modeled as a sequence of transformations applied on initial specifications. In the database domain too, most engineering processes can be described as schema transformations. First, this paper presents a wide spectrum specification model intended to describe data structures at different abstraction levels and according to the current modelling paradigms. This model includes the representation of statistical data about the instances of the data structures. Then, it defines and discusses the concepet transformation. The properties of specification preservation is defined and applied to two important aspects, namely semantics discussed and illustrated by some aspects of DB-MAIN, a representative CASE tool based on this approach.

The transformational approach to database engineering

In the database engineering realm, the merits of transformational approaches, that can produce in a systematic way correct, compilable and efficient database structures from abstract models, has long be recognized. Transformations that are proved to preserve the correctness of the source specifications have been proposed in virtually all the activities related to data structure engineering: schema normalization, logical design, schema integration, view derivation, schema equivalence, data conversion, reverse engineering, schema optimization, wrapper generation and others. This paper addresses both fundamental and practical aspects of database transformation techniques. The concept of transformation is developed, together with its properties of semantics-preservation (or reversibility). Major database engineering activities are redefined in terms of transformation techniques, and the impact on CASE technology is discussed. These principles are applied to database logical design and database reverse engineering. They are illustrated by the use of DB-MAIN, a programmable CASE environment that provides a large transformational toolkit.

Data Reverse Engineering using System Dependency Graphs

Data reverse engineering (DRE) is a complex and costly process that requires a deep understanding of large data-intensive software systems. This process can be made easier with the use of program understanding methods and tools. In this paper, we focus on the program slicing technique and we show how it can be adapted to support DRE. We present a DML-independent SDG construction approach involving the analysis of database operations as a first stage. We describe a tool based upon this approach and we report on two industrial DRE projects