An Object Relational Database Management System - 1371 Words

INTRODUCTION An object-relational database management system (ORDMS) is a DBMS that supports both relational and object-oriented functions. SQL:1999 seems like the most innovative update to the language since its induction, largely because of the adoption of object-oriented related upgrades. COLLECTION TYPES â€Å"A collection is an ordered group of elements, all of the same type.† (Oracle 2002) With this addition it became possible to use set operators which allows for a single result from two queries. Operator Returns UNION All distinct rows selected by either query UNION ALL All rows selected by either query, including all duplicates INTERSECT All distinct rows selected by both queries MINUS All distinct rows selected by the first query†¦show more content†¦3. Varrays – this also uses sequential numbering as the key which makes its use ideal when trying to access its contents in sequence. However, because varrays holds a fixed number of elements, the method should be used when the amount of elements is predetermined. USER-DEFINED DATA TYPES (UDT) UDTs have numerous ways of implementation. They act much like the typedefs in the C language and can be used as defining a table, element, or even column type. Distinct user-defined types of power allow the use of name equivalence instead of structural equivalence. Compatible operations can be achieved by using the CAST operation. Structured user-defined types allow for type inheritance which creates subtypes that inherit attributes and functions of their super types or references types. â€Å"There are several reasons why UDT s are useful within an object database† (Burleson Consulting 2014): 1. Encapsulation – The existence of a complete entity. This means once the data definitions, default values, and value constraints are defined uniformity and consistency are guaranteed. Because of this, once nested UDTs will retain uniformity throughout the database. 2. Reusability – Refers to the reuse of the hierarchy of common data structures which we learned in a previous course saves coding time and insures uniformity. 3. Flexibility – This is obvious in the name, User-Defined Data Type, as it allows great flexibility when creating