Rule 1: Map all concrete-problem domain classes to the RDBMS tables. Also, if an abstract Problem Domain class has multiple direct subclasses, map the abstract class to a RDBMS table. Rule 2: Map single-valued attributes to columns of the tables. Rule 3: Map methods to stored procedures or to program modules. Rule 4: Map single-valued aggregation and association relationships to a column that can store the key of the related table, i.e., add a foreign key to the table. Do this for both sides of the relationship. (one to one) Rule 5: Map multivalued attributes and repeating groups to new tables and create a one-to-many association from the original table to the new ones. Rule 6: Map multivalued aggregation and association relationships to a new associative table that relates the two original tables together. Copy the primary key from both original tables to the new associative table, i.e., add foreign keys to the table. (many to Rule 7: For aggregation and association relationships of mixed type, copy the primary key from the single-valued side (1..1 or 0.. of the relationship to a new column in the table on the multivalued side (1..* or 0..*) of the relationship that can store the key of the related table, i.e., add a foreign key to the table on the multivalued side of the relationship. (many to one or one to many For generalization/inheritance relationships: Rule 8a: Ensure that the primary key of the subclass instance is the same as the primary key of the superclass. The multiplicity of this new association from the subclass to the "superclass" should be 1..1. If the superclasses are concrete, that is, they can be instantiated themselves, then the multiplicity from the superclass to the subclass is 0..1, otherwise, it is 1..1. Furthermore, an exclusive-or (XOR) constraint must be added between the associations. Do this for each superclass. OR Rule 8b: Flatten the inheritance hierarchy by copying the superclass attributes down to all of the subclasses and remove the superclass from the design.* * It is also a good idea to document this modification in the design so that in the future, modifications to the design can be maintained easily.

Rule 1: Map all concrete-problem domain classes to the RDBMS tables. Also, if an abstract Problem Domain class has multiple direct subclasses, map the abstract class to a RDBMS table. Rule 2: Map single-valued attributes to columns of the tables. Rule 3: Map methods to stored procedures or to program modules. Rule 4: Map single-valued aggregation and association relationships to a column that can store the key of the related table, i.e., add a foreign key to the table. Do this for both sides of the relationship. (one to one) Rule 5: Map multivalued attributes and repeating groups to new tables and create a one-to-many association from the original table to the new ones. Rule 6: Map multivalued aggregation and association relationships to a new associative table that relates the two original tables together. Copy the primary key from both original tables to the new associative table, i.e., add foreign keys to the table. (many to Rule 7: For aggregation and association relationships of mixed type, copy the primary key from the single-valued side (1..1 or 0.. of the relationship to a new column in the table on the multivalued side (1..* or 0..) of the relationship that can store the key of the related table, i.e., add a foreign key to the table on the multivalued side of the relationship. (many to one or one to many For generalization/inheritance relationships: Rule 8a: Ensure that the primary key of the subclass instance is the same as the primary key of the superclass. The multiplicity of this new association from the subclass to the "superclass" should be 1..1. If the superclasses are concrete, that is, they can be instantiated themselves, then the multiplicity from the superclass to the subclass is 0..1, otherwise, it is 1..1. Furthermore, an exclusive-or (XOR) constraint must be added between the associations. Do this for each superclass. OR Rule 8b: Flatten the inheritance hierarchy by copying the superclass attributes down to all of the subclasses and remove the superclass from the design. * It is also a good idea to document this modification in the design so that in the future, modifications to the design can be maintained easily.

Principles of Information Systems (MindTap Course List)

12th Edition

ISBN:9781285867168

Author:Ralph Stair, George Reynolds

Publisher:Ralph Stair, George Reynolds

Chapter5: Database Systems And Applications

Section: Chapter Questions

Problem 4PSE: Using a graphics program, develop an entity-relationship diagram for a database application for an...

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