The document discusses several implementation challenges for object relational database systems (ORDBMS). It outlines issues related to storage and access methods for efficiently storing and accessing different data types like ADTs and structured objects. Query processing is more complex due to support for ADTs and user-defined functions that can introduce bugs or security issues. The query optimizer must also understand the new functionality to optimize queries appropriately.

1. Implementation Issues
with
Object Relational Database
System

2. 04/21/172
Several Implementation Challenges Due to
Enhanced Functionality of ORDBMS
 Storage & Access Method
 Query Processing
 Query Optimization

3. 04/21/173
Storage & Access Method
 efficiently store ADT objects and structure objects and provide efficient
indexed access to both
● Large ADTs, like BLOBs(Binary Large Object),
require special storage, typically in a different
location on disk from the tuples that contain
them
● Disk-based pointers are maintained from the
tuples to the
objects they contain.
● A complication arises with array types. Arrays
are broken
into contiguous chunks, which are then stored in
some order
on disk.

4. 04/21/174
Query Processing
 ADTs and structured types call for new functionality in
processing queries
● To register an aggregation function, a user must implement three methods,
which we call initialize, iterate and terminate.
● ADTs give users the power to add code to the DBMS; this power can be abused.
● A buggy or malicious ADT method can bring down the database server or even
corrupt the database.
● User-defined ADT methods are very expensive

5. 04/21/175
Query Optimization
 To handle new query processing functionality, an optimizer must know
about the new functionality and use it appropriate

6. 04/21/175
Query Optimization
 To handle new query processing functionality, an optimizer must know
about the new functionality and use it appropriate