Multidimensional (MD) modeling is the foundation of data warehouses, MD databases, and On-Line Analytical Processing (OLAP) applications. In the past few years, there have been some proposals for representing the main MD properties at the conceptual level providing their own notations. In this paper, we present an extension of the Unified Modeling Language (UML), by means of stereotypes, to elegantly represent main structural and dynamic MD properties at the conceptual level. We make use of the Object Constraint Language (OCL) to specify the constraints attached to the defined stereotypes, thereby avoiding an arbitrary use of these stereotypes. The main advantage of our proposal is that it is based on a well-known standard modeling language, thereby designers can avoid learning a new specific notation or language for MD systems. Finally, we show how to use these stereotypes in Rational Rose 2000 for MD modeling.

The Unified Modeling Language (UML) has become the de facto standard for object-oriented analysis and design, providing different diagrams for modeling different aspects of a system. In this paper, we present the development of multidimensional (MD) models for data warehouses (DW) using UML package diagrams. In this way, when modeling complex and large DW systems, we are not restricted to use fiat UML class diagrams. We present design guidelines and illustrate them with various examples. We show that the correct use of the package diagrams using our design guidelines will produce a very simple yet powerful design of MD models. Furthermore, we provide a UML extension by means of stereotypes of the particular package items we use. Finally, we show how to use these stereotypes in Rational Rose 2000 for MD modeling.

OLAP tools divide concepts based on whether they are used as analysis dimensions, or are the fact subject of analysis, which gives rise to star shape schemas. Operations are always provided to navigate inside such star schemas. However, the navigation among different stars is usually overlooked. This paper studies different kinds of Object-Oriented conceptual relationships (part of UML standard) between stars (namely Derivation, Generalization, Association, andFlow) that allow to drill across them.

In the last years, lots of work have been devoted to multidimensional modeling, star shape schemas and OLAP operations. However, “drill-across ” has not captured as much attention as other operations. This operation allows to change the subject of analysis keeping the same analysis space we were using to analyze another subject. It is assumed that this can be done if both subjects share exactly the same analysis dimensions. In this paper, besides the implementation of an algebraic set of operations on a RDBMS, we are going to show when and how we can change the subject of analysis in the presence of semantic relationships, even if the analysis dimensions do not exactly coincide.

... as a very powerful mechanism for discovering crucial business information. Considering the extreme importance of the information managed by these kinds of applications, it is essential to specify security measures from the early stages of the DW design in the MD modeling process, and enforce them. In the past years, some proposals for representing main MD modeling properties at the conceptual level have been stated. Nevertheless, none of these proposals considers security issues as an important element in its model, so they do not allow us to specify confidentiality constraints to be enforced by the applications that will use these MD models. In this paper, we will discuss the specific confidentiality problems regarding DWs as well as present an extension of the Unified Modeling Language for specifying security constraints in the conceptual MD modeling, thereby allowing us to design secure DWs. One key advantage of our approach is that we accomplish the conceptual modeling of secure DWs independently of the target platform where the DW has to be implemented, allowing the implementation of the corresponding DWs on any secure commercial database management system. Finally, we will present a case study to show how a conceptual model designed with our approach can be directly implemented on top of Oracle 10g.

Abstract: Multidimensional (MD) modeling is the basis for Data warehouses (DW), multidimensional databases (MDB) and On-Line Analytical Processing (OLAP) applications. In this paper, we present how the Unified Modeling Language (UML) can be successfully used to represent both structural and dynamic properties of these systems at the conceptual level. The structure of the system is specified by means of a UML class diagram that considers the main properties of MD modeling with minimal use of constraints and extensions of the UML. If the system to be modeled is too complex, thereby leading us to a considerable number of classes and relationships, we describe how to use the package grouping mechanism provided by the UML to simplify the final model. Furthermore, we provide a UML-compliant class notation (called cube class) to represent OLAP users ' initial requirements. We also describe how we can use the UML state and interaction diagrams to model the behavior of a data warehouse system. To facilitate the interchange of conceptual MD models, we provide a Document Type Definition (DTD) which allows us to represent the same MD modeling properties that can be considered by using our approach. From this DTD, we can directly generate valid eXtensible Markup Language (XML) documents that represent MD models at the conceptual level. We believe that our innovative approach provides a theoretical foundation for simplifying the conceptual design of MD systems and the examples included in this paper clearly illustrate the use of our approach.

Extraction-Transformation-Loading (ETL) tools are pieces of software responsible for the extraction of data from several sources, their cleansing, customization and insertion into a data warehouse. In this paper, we propose a methodology for the earliest stages of the data warehouse design, with the goal of tracing the analysis of the structure and content of the existing data sources and their intentional mapping to the common conceptual data warehouse model. The methodology comprises a set of steps that can be summarized as follows: (a) identification of the proper data stores; (b) candidates and active candidates for the involved data stores; (c) attribute mapping between the providers and the consumers, and (d) annotation of the diagram with runtime constraints.

This paper introduces a Conceptual Data Model for Data Warehouse including multidimensional aggregation. It is based on Entity-Relationships data model. The conceptual data model gracefully extends standard Entity-Relationship data model with multidimensional aggregated entities. The model has a clear mathematical theoretic semantics grounded on standard ER semantics and the GMD logic-based multidimensional data model. The aim of this work is not to propose yet another conceptual data model, but to find the most general and precise formalism considering all the proposals for a conceptual data model in the data warehouse field, making therefore a possible formal comparison of the differences of the models in the literature, and to study the formal properties or extensions of such data models. 1

At present, it is very difficult to develop a methodology that fulfills all criteria and comprises all security constraints in the successful design of data warehouses. If that methodology were developed, its complexity would hinder its success. The solution, therefore, would be an approach in which techniques and models defined by the most accepted model standards were extended by integrating the necessary security aspects that at this moment in time are not covered by the existing methodologies. In this paper, we will focus on solving confidentiality problems in the conceptual modelling of data warehouses by defining a profile using the UML 2.0 extensibility mechanisms. In addition, we define an OCL extension that allows us to specify the security constraints of the elements in conceptual modelling of data warehouses and we apply this profile to an example.

A data warehouse (DW) is a complex information system primarily used in the decision making process by means of On-Line Analytical Processing (OLAP) applications. Although various methods and approaches have been presented for designing dierent parts of DWs, such as the conceptual and logical schemas or the Extraction-TransformationLoading (ETL) processes, no general and standard method exists to date for dealing with the whole design of a DW. In this paper, we ll this gap by presenting a method based on the Unied Modeling Language (UML) that allows the user to tackle all DW design phases and steps, from the operational data sources to the nal implementation and including the denition of the ETL processes. The main advantages of our proposal are: the use of a standard modeling notation (UML) in the models accomplished in the dierent design phases, the integration of dierent design phases in a single and coherent framework and the use of a grouping mechanism (UML packages) that allows the designer to layer the models according to dierent levels of detail. Finally, we also provide a set of steps that guide the DW design.