| Abstract |
Object-oriented databases have quite complicated needs concerning the user-friently data entry and the interactive update, because of the multiple relations that may hold among the objects. In spite of the difficulties tha may exist, there is a need for a system which provides the users with the capability to enter data in a friendly way. It is also desirable for this system to guide and help the user in each step and in the same time to hold the user's operations under control. This thesis deals with the construction of an interactive tool for information acquisition to object-oriented databases. The tool, which is called Data Entry Form(DEF), is a part of the Semantic Index System (SIS). It is used for the update of databases that are based on the data model of the knowledge presentation languages Telos. The DEF offers a complete set of operations that covers the whole set of Telos primitive updates. The operations in the DEF are implemented by a set of update forms, which provides the user with the capability to update the database objects interactively. These forms are related with operations for creation, deletion, rename, instantiation, generalization and attribution for nodes and attributes. Aprocess model is used, in order to describe the databases interactive update process. This model is based on the task-oriented approach. A task is defined by the objects that are allowed to be updated and the operations that can be performed on these objects. In this way, parts of the database can be isolated and updated indepentendly from others, using predefined operations. The system users can update the database using the tasks which are assigned to them. The DEF, based on the prementioned model, uses the task-oriented approach. The DEF has the ability to preserve a set of integrity constraints which are not checked by the semantic checker of the SIS system. This is accomplished by the use of an integrity constraint model which has been developed. Also the tool provides facilities for granding permission to the users. Furthermore the tool provides acceleration facilities and guiding mechanisms during the interactive update. The DEF can easily be adapted to the needs of an application, without the use of a programming language. For this purpose, it is sufficient to adapt the process and the integrity constraint model to the application. The tool has been tested in several SIS applications, producing quite satisfactory results.
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Διαλογική Ενημέρωση Οντοκεντρικών Βάσεων Δεδομένων
