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Agenda. TMA02 M877 Block 1 - Foundations. Requirements for New Database Technology. Multiple Databases Block 2 - Distributed Data Management Additional Data Requirements Block 3 – Databases with Objects Block 4 – Databases with Multimedia Developments in Using Data
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Agenda • TMA02 • M877 Block 1 - Foundations
Requirements for New Database Technology • Multiple Databases • Block 2 - Distributed Data Management • Additional Data Requirements • Block 3 – Databases with Objects • Block 4 – Databases with Multimedia • Developments in Using Data • Block 5 – Decision Support Systems
Why Multiple Databases? • User want direct control of own data • Purchase of third-party software package • An organisation may develop a number of systems with separate databases.
Why Multiple Database? • Off-line/remote access/update of data. • Replicated Database System
Uses of Basic Replications • Information distribution • Information off-loading
Composite Value • Composite value is composed of a number of parts. • For example, address is composed of flat/room, floor, block, building/estate, street and district. • It needs to be a single value in order to be perceived as a unit for updating, and to preserve the relational principle of only having an atomic value for each column in a row. • It needs to be a composite value so that it can have a number of parts, together with functions to extract from that value the parts we need to use in queries.
Complex Data • Document, e.g. txt, doc, pdf etc • Image • Audio • Video
Developments in Using Data • Decision support system • Use data as an information resource rather than just to support the daily operation of an organization • Develop a separate database specially designed to satisfy decision support requirements, which is known as data warehouse/data mart. • Characteristics of data warehouses are:- • Massive data • Queries are mainly concerned with trends and summaries of data over time (OLAP) • Design needs to allow for the specialized usage. • Find 'rules' about certain properties of the data in some table of data – data mining.
Using Java • JDBC – Java Database Connectivity • SQLJ • JDO – Java Data Object
Special-purpose Database Systems • Repositories • Temporal databases • Spatial databases • Logic databases • Document databases • Multimedia databases