||Oracle Tips by Burleson
Preaggregation of data
When you pre-summarize data with
materialized views, you don’t need to change your SQL! Oracle has a
super-cool feature called query re-write where Oracle will
automatically know when your SQL can use a pre-summarized result.
So, I have my data, and I want to start
building my database. How can I visualize my data and go through
the normalization process with out constantly recreating the
database? For this, you want to use the Entity Relation Diagram.
Entity Relation Modeling
Data modeling is a method for developing the
structure of the database. It uses various tools to define the
data, relationships, semantics and data consistency requirements.
The Entity Relation Diagram (ERD) is where most designers start when
creating and normalizing a database. An ERD normally starts on
paper with a general layout of the database data entities and their
The entity/relation model was first
introduced by Professor Emeritus Peter Chen from the University of
Louisiana, and it is sometimes called a Chen diagram. In the 25
years since the introduction of this model, many permutations have
been created, but the basic principles of entity/relations modeling
While an E/R model may be free of redundant
information, it is impossible to implement the model in a relational
database without introducing redundancy to support the data
relationships. For example, if a data model was implemented using a
pointer-based DBMS, such as IMS, pointers would be used to establish
relationships between entities.
At some point, the diagram becomes unwieldy
on paper and an ERD tool is used to graphically finish the design.
In a nutshell, the ER diagram shows the data tables, and more
importantly, it shows the one-to-many and many-to-many data
The above book excerpt is from:
Fast writing SQL Reports with SQL*Plus
Col. John Garmany