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A C++ Binding for Penguin: a System for Data Sharing among Heterogeneous Object Models
- 4th Int. Conf. Foundations of Data Organization and Algorithms
, 1993
"... . The relational model supports the view concept, but relational views are limited in structure. OODBMSs do not support the view concept, so that all applications must share the same arrangement of object classes and inheritance. We describe the Penguin system and its support for the view concept. E ..."
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Cited by 8 (4 self)
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. The relational model supports the view concept, but relational views are limited in structure. OODBMSs do not support the view concept, so that all applications must share the same arrangement of object classes and inheritance. We describe the Penguin system and its support for the view concept. Each application can have its own arrangement of object classes and inheritance, and these are defined as views of an integrated, normalized conceptual data model, in our case the Structural Model. We define view-objects in a language-independent manner on top of the conceptual data model. These view-objects can be complex objects supporting a composite structure. We discuss the extension of Penguin to support PART-OF (reference) and IS-A graphs for composite view-objects. We also discuss the C++ binding to Penguin, where C++ code is generated for object classes corresponding to the view-objects along with basic operations on them (creation, query, navigate, browsing, and update). 1 Introduct...
Implementation of Object View Query on a Relational Database
- In Data and Knowledge Systems for Manufacturing and Engineering
, 1994
"... We present the implementation of the query function for the Penguin system. Penguin is an object-oriented database system that supports multiple object views on a relational database. It enables many applications to share a database using different object schemata. Also, users can take queries for t ..."
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We present the implementation of the query function for the Penguin system. Penguin is an object-oriented database system that supports multiple object views on a relational database. It enables many applications to share a database using different object schemata. Also, users can take queries for the Penguin database in their applications, to retrieve objects on the heterogeneous data model. The query function is very powerful for manufacturing and engineering purposes, that is, connections between relations and methods defined by users in applications are available in query requests. We introduce the object model and the query execution algorithm of the Penguin system with an example for a steel plant, and show the system configuration for the implementation of the query function. 1 Introduction In the field of manufacturing and engineering, an important requirement for database systems is the handling of complicated structures of data, such as manufacturing design data and producti...
Querying Heterogeneous Object Views of a Relational Database
- In Int. Symp. on Next Generation Database Systems and Their Applications (NDA
, 1993
"... We present the query processing algorithm for the Penguin system. Penguin supports multiple object views on a relational database, so that data may be shared by applications with heterogeneous object schemata. Penguin also offers an interface for the C++ language. We have developed a query processin ..."
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We present the query processing algorithm for the Penguin system. Penguin supports multiple object views on a relational database, so that data may be shared by applications with heterogeneous object schemata. Penguin also offers an interface for the C++ language. We have developed a query processing algorithm for querying composite object views. The query algorithm takes a query on a composite object view, and decomposes it into partial queries on the relational database. The final query result is composed from those partial results. We also discuss an optimization for reducing the volume of temporary data created in query processing. 1 Introduction Object-oriented programming is becoming quite prevalent for its benefits of software productivity, quality and reusability. Software developers are eager to adopt the object-oriented approach in new applications. On the other hand, the relational model introduced by Codd [7] is so widely accepted that most new database applications use re...
Consistency and Performance of Concurrent Interactive Database Applications
"... In many modern database applications, there is an emerging need for interactive environments where users directly manipulate the contents of the database. Graphical user interfaces (GUIs) display images of the database which must re ectaconsistent up{to{date state of the data with minimum perceivabl ..."
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In many modern database applications, there is an emerging need for interactive environments where users directly manipulate the contents of the database. Graphical user interfaces (GUIs) display images of the database which must re ectaconsistent up{to{date state of the data with minimum perceivable delay to the user. Moreover, the possibility of several applications concurrently displaying di erent views of the same database increases the overall system complexity. In this paper, we show how design, performance and concurrency issues can be addressed by adapting existing database techniques. We propose the use of suitable display schemas whose instances compose active views of the database, an extended client caching scheme which is expected to yield signi cant performance bene ts and a locking mechanism that maintains consistency between the GUIs and the database. 1
Efficient Refreshment of Data Warehouse Views
, 1997
"... : A data warehouse is a view on a set of distributed and possible loosely coupled source databases. For efficiency reasons a warehouse should be maintained as a materialized view. Therefore, efficient incremental algorithms must be used to periodically refresh the data warehouse. It is possible and ..."
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: A data warehouse is a view on a set of distributed and possible loosely coupled source databases. For efficiency reasons a warehouse should be maintained as a materialized view. Therefore, efficient incremental algorithms must be used to periodically refresh the data warehouse. It is possible and desirable to separate the process of warehouse refreshment from the process of warehouse use. In this paper we describe and compare view refreshment algorithms that are based on different combinations of materialized views, partially materialized views, and pointers. Our contribution is twofold. First, our algorithms and data structures are designed to minimize network communication and interactions between the warehouse and the source databases. The minimal set of data that is necessary for both warehouse refreshment and warehouse use is stored on the warehouse. Second, we describe the results of an experiment comparing these methods with respect to storage overhead and I/O. Briefly, the ex...
