DBMS Models - Narrative
Links to the essential reading, resources, activities, databases, advanced topic forum and assessment upload referred to in this narrative are in the theme block in myCourse.
The relational model remains the most widely used DBMS model in industry for many reasons including meeting organisational needs, it is well understood and there are many robust and mature products based on the relational model. However, there are other data models including object and XML-based that may be more appropriate for particular organisations and applications.
Industry DBMS software such as Oracle normally have well established functionality for ensuring database integrity - in particular, declarative primary/referential/domain integity constraints. This theme builds on what you have studied in earlier years of the courses in respect of implementing, documenting and managing (using the data dictionnary) declarative constraints.
Database triggers offers useful functionality for ensuring integrity (where declarative integrity is not possible), and for database audit and security applications. We will therefore develop further your skills in the design, implementation and testing of database triggers. We will also apply them to implement data replication in the "Improving Data Access by Distribution and Replication" theme. We will start with a "Developing an Audit Trigger" practice activity to help consolidate these integrity and database trigger skills.
Oracle now incorporates XML functionality with its now substantial XMLDB product, and we will focus on this technology. We will apply some of the basic technology in meeting typical business requirements. XML was introduced in year 2, and so you should first revise this using the myCourse site and the many web XML resources available. We will focus on how XML relates to databases in the context of Oracle. In particular, we will use the XML datatype and SQL/XML for the update, insert, delete and retrieval of XML content in the databases. This complements what is covered in the Emerging Web Technologies unit that some of you are also studying.
The essential reading for this theme is Ritchie - XML and Databases - Ch.11 and the "XML and Databases" practice activity should help develop your skills.
The assessed activity involves developing the integrity of OE product and price information and its external availability using XML functionality in the database. The advanced topic and forum is the emerging XQuery language.