Database Reference
In-Depth Information
I. The existence condition in relational calculus is similar to the JOIN oper-
ation in relational algebra.
J. If a commercial language can perform every operation in relational
algebra, then the commercial language is said to be relationally complete.
2. Describe the data manipulation method of relational algebra. Compare this
with the relational calculus method and explain the difference. Specify a
typical data query in a banking environment. Find the result for this query
using both generic languages.
3. As a data modeler for a small appliance store, describe the steps you would
take to create a relational data model.
4. A large manufacturer of electronic components wants to implement a rela-
tional database. Which method would you adopt to create the relational data
model? Give a list of the important tables in your data model.
5. The relational data model consists of two-dimensional tables, not random
tables but tables that conform to relational rules. What are these rules and
properties of a relational model? Describe the rules.
Search WWH ::
Custom Search