In this paper, we summarize our experience in developing and using the Snowball Rapid Systems Engineering Tool. We highlight the techniques we used such as: Rapid Systems Engineering(TM) (RASE(TM)), Instant Code Gener...
详细信息
ISBN:
(纸本)0818684828
In this paper, we summarize our experience in developing and using the Snowball Rapid Systems Engineering Tool. We highlight the techniques we used such as: Rapid Systems Engineering(TM) (RASE(TM)), Instant Code Generation(TM), Instant Reverse Engineering(TM), and Dynamic Document Capture(TM). We elaborate on the implementation of these techniques and their advantages to systems development, problems rye encountered while developing Snowball, and we briefly discuss our experience while using Snowball to develop a large Internet-based object-oriented database system.
Several researchers have considered integrating multiple unstructured, semi-structured, and structured data sources by modeling all sources as edge labeled graphs. Data in this model is self-describing and dynamically...
详细信息
ISBN:
(纸本)3540648232
Several researchers have considered integrating multiple unstructured, semi-structured, and structured data sources by modeling all sources as edge labeled graphs. Data in this model is self-describing and dynamically typed, and captures both schema and data information. The labels are arbitrary atomic values, such as strings, integers, reals, etc., and the integrated data graph is stored in a unique data repository, as a relation of edges. The relation is dynamically typed, i.e. each edge label is tagged with its type. Although the unique, labeled graph repository is flexible, it looses all static type information, and results in severe efficiency penalties compared to querying structured databases, such as relational or object-oriented databases. III this paper we propose an alternative method of storing and querying semi-structured data, using storage schemas, which are closely related to recently introduced graph schemas [BDFS97]. A storage schema splits the graph's edges into several relations, some of which may have labels of known types (such as strings or integers) while others may be still dynamically typed. We show here that all positive queries in UnQL, a query language for semistructured data, can be translated into conjunctive queries against the relations in the storage scheme. This result may be surprising, because UnQL is a powerful language, featuring regular path expressions, restructuring queries, joins, and unions. We use this technique in order to translate queries on the integrated, semi-structured data into queries on the external sources. In this setting the integrated semi-structured data is not materialized but virtual and the problem is to translate a query against the integrated view, possibly involving regular path expressions and restructuring, into queries which can be answered by the external sources. Here we use again the storage schema in order to split the graph into relations according to their sources. Any positive UnQL query is
In conventional computer supported cooperative work (CSCW) systems, usually only one video-based environment is shared by all the users. In this paper, we will show that multiple environments are required and they can...
详细信息
ISBN:
(纸本)0818683082
In conventional computer supported cooperative work (CSCW) systems, usually only one video-based environment is shared by all the users. In this paper, we will show that multiple environments are required and they can be realized utilizing object-oriented database technology. A cooperative work environment can be regarded as a room where users work together by sharing documents and equipment through available communication facilities. In one environment, users, documents and equipment are handled as objects and these different types of objects have some attributes and methods in common, such as location attributes and layout methods. However, using the Existing concepts of the conventional object-oriented model, such as class, complex object and collection object, it is difficult to define one environment namely a set with different types of elements brit having some attributes and methods in common. The object deputy model introduced by the authors can be ea:tended to formulate such Environments. Since the object deputy model can uniformly handle object views, roles, migration and multiple inheritance, we can realize flexible, dynamic and powerful environments based on object-oriented databases.
Three nontrivial limitations of the existing Java™ technology are considered from the viewpoint of object-oriented database technology. The limitations are: Lack of support for orthogonal persistence, lack of parametr...
详细信息
作者：
Morris, APetry, FETulane Univ
Dept Elect Engn & Comp Sci Ctr Intelligent & Knowledge Based Syst New Orleans LA 70118 USA
Fuzzy set approaches are particularly suitable for issues of modeling uncertainty in spatial data. We survey where and how uncertainty may appear in spatial data. We consider the issues involved in developing the mode...
详细信息
ISBN:
(纸本)0780344537
Fuzzy set approaches are particularly suitable for issues of modeling uncertainty in spatial data. We survey where and how uncertainty may appear in spatial data. We consider the issues involved in developing the modeling of uncertain spatial data in the framework of object-oriented databases. Finally we outline the issues in an approach for implementing fuzzy spatial queries in a commercially available object-oriented database.
Time is an important aspect of all real-woild pheiiümeria. Events occur at specilic points in time;objrcis and their rela-tionshiips exist and change over time. Tradii ionally, temporal database systems allow dif...
详细信息
We present in this paper a generic object-oriented benchmark (the object Clustering Benchmark) that has been designed to evaluate the performances of clustering policies in object-oriented databases. OCB is generic be...
详细信息
ISBN:
(纸本)3540642641
We present in this paper a generic object-oriented benchmark (the object Clustering Benchmark) that has been designed to evaluate the performances of clustering policies in object-oriented databases. OCB is generic because its sample database may be customized to fit the databases introduced by the main existing benchmarks (e.g., OO1). OCB's current form is clustering-oriented because of its clustering-oriented workload, but it can be easily adapted to other purposes. Lastly, OCB's code is compact and easily portable. OCB has been implemented in a real system (Texas, running on a Sun workstation), in order to test a specific clustering policy called DSTC. A few results concerning this test are presented.
According to the ANSI/SPARC architecture, external schemas are derived from the database conceptual schema. In object-oriented databases (OODBs), an external schema may include classes defined in the conceptual schema...
详细信息
ISBN:
(纸本)0818683082
According to the ANSI/SPARC architecture, external schemas are derived from the database conceptual schema. In object-oriented databases (OODBs), an external schema may include classes defined in the conceptual schema just as it may also contain derived classes which are directly or indirectly defined on the basis of conceptual schema classes. In the definition of derived classes in OODBs three main issues have to be resolved, namely: the integration of derived classes with other classes in an object schema;the definition of classes with new objects;and the transmission of modifications between the objects in derived classes and those of the classes from which they are defined. A solution to the first issue was proposed in [18] and [19]. In this paper, the two remaining issues are further studied and new conceptual level solutions are put forward. Our proposals are informally illustrated through some examples.
Data versioning is important for many applications such as CASE, CAD and CAM. New design objects in these applications are usually created from existing ones because they share a large degree of similarity. In this pa...
详细信息
ISBN:
(纸本)0818691832
Data versioning is important for many applications such as CASE, CAD and CAM. New design objects in these applications are usually created from existing ones because they share a large degree of similarity. In this paper, we propose a difference-based version model for object-oriented database systems. The large object is stored only the difference data from its parent version. To show the feasibility of this version model, a prototype is implemented and a performance study on the version storage and access time is made. We observe from this study that, when the difference between two versions is less than 10%, the system has the best storage efficiency and incurs the least overhead in access time. Our implementation experience also shows that the proposed version model can be implemented as an independent module to plug in a data storage system easily.
In the context of the object-oriented data model, a compile-time approach is given that provides for a significant reduction of the amount of run-time transaction overhead due to integrity constraint checking. The hig...
详细信息
ISBN:
(纸本)3540648232
In the context of the object-oriented data model, a compile-time approach is given that provides for a significant reduction of the amount of run-time transaction overhead due to integrity constraint checking. The higher-order logic Isabelle theorem prover is used to automatically prove which constraints might, or might not be violated by a given transaction in a manner analogous to the one used by Sheard and Stemple (1989) for the relational data model. A prototype transaction verification tool has been implemented, which automates the semantic mappings and generates proof goals for Isabelle. Test results are discussed to illustrate the effectiveness of our approach.
暂无评论