Databases Reference
In-Depth Information
Exhibit 37-1. Internet-based client/server communication.
Furthermore, distributed object management technologies need to be exam-
ined for heterogeneous database integration through the Internet. This
chapter discusses the impact of the Internet on various DBMS functions.
DBMS FUNCTIONS
Key DBMS functions include data representation, query management,
transaction management, storage management, security management,
integrity management, and metadata management. For an Internet data-
base, functions such as browsing and filtering also have to be managed.
Data Representation
Various data representation schemes have been proposed for text data-
bases, including standard generalized markup language (SGML), hypertext
markup language (HTML), and office document architecture (ODA). How-
ever, a considerable amount of data will also be stored in structured (i.e.,
relational and object-oriented) databases. Appropriate data models for
representing structured as well as unstructured databases include inte-
grated object-oriented, relational, and hypertext-based data models for
Internet database management. Currently there are no agreed-on standard
data models; appropriate mappings between the standards and the hetero-
geneous data models used by the databases must also be developed.
Query Management
Query management involves developing language and processing tech-
niques. The query language depends to a great extent on the data model used.
Languages based on SQL are popular for relational as well as nonrelational
database systems. For example, object-oriented DBMSs use variations of SQL
for database access. An appropriate SQL-based language needs to be devel-
oped for accessing structured and unstructured databases. SQL extensions
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