ITM 500 Chapter Notes -Oracle Vm Server For Sparc, Unique Key, Data Modeling

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CA ERwin Data Modeler (ERwin) is a software tool for data modeling (data requirements analysis,
database design etc) of custom developed information systems, including databases of transactional
systems and data marts.
Logical Data Modeling: Logical only models may be created, from which physical models may be
derived. Also combinations logical and physical models are supported. Supports entity-type and
attribute logical names and descriptions, logical domains and data types, as well as relationship
naming.
Physical Data Modeling: Physical only models may be created as well as combination logical and
physical models. Supports table and column naming and descriptions, user defined data types,
as well as primary key, foreign key, alternate key and check constraint definition and naming.
Support for indexes, views, stored procedures and triggers is also included.
Choose Logical/Physical as the new model type. This choice will allow us to switch back and
forth easily between a logical model (ER Diagram) and a physical model (database schema).
Preferences
1. From the Format->Entity Display menu, make sure that Primary Key Designator is checked
2. From the Format->Entity Display menu, make sure that Foreign Key Designator (FK) is
unchecked.
3. From the Format->Entity Display menu, make sure that Show Migrated Attributes is unchecked.
4. From the Format->Relationship Display, make sure that Verb Phrase is checked.
Diagramming notations: In ERwin, click on Model->Model Properties
Notation->Change the 2 to IE (Information Engineering)
("Crows Foot") notation
ERwin supports the creation of relationships with three basic kinds of connectivity:
one-to-one
one-to-many
o ERwin allows us to distinguish between
Identifying- An identifying relationship is a relationship between two
entities in which an instance of a child entity is identified through its
association with a parent entity, which means the child entity is
dependent on the parent entity for its identify and cannot exist without it.
In an identifying relationship, one instance of the parent entity is related to
multiple instances of the child.
non-identifying - A non-identifying relationship is a relationship between
two entities in which an instance of the child entity is not identified through
its association with a parent entity, which means the child entity is not
dependent on the parent entity for its identify and can exist without it. In a
non identifying relationship, one instance of the parent entity is related to
multiple instances of the child.
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Document Summary

Ca erwin data modeler (erwin) is a software tool for data modeling (data requirements analysis, database design etc) of custom developed information systems, including databases of transactional systems and data marts. Logical data modeling: logical only models may be created, from which physical models may be derived. Also combinations logical and physical models are supported. Supports entity-type and attribute logical names and descriptions, logical domains and data types, as well as relationship naming. Physical data modeling: physical only models may be created as well as combination logical and physical models. Supports table and column naming and descriptions, user defined data types, as well as primary key, foreign key, alternate key and check constraint definition and naming. Support for indexes, views, stored procedures and triggers is also included. Choose logical/physical as the new model type. This choice will allow us to switch back and forth easily between a logical model (er diagram) and a physical model (database schema).

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