Definitions 1Generalization - the process of defining a more general entity type from a set of more specialized entity types Weak Entity type - an entity type whose existence depends on another entity type a Composite Key - is a set of more than one key that, together, uniquely identifies each record. Foreign Key - is a key in some table which uniquely identifies rows in another table The entity integrity rule - The primary key for a row is unique, and any primary key is not null Primary Key
Primary Key Composite Key
CompKey Definitions ContinuedReferential Integrity Constraint - each foreign key value must match a primary key value in the other relation Meta-Data - Data that describes the properties of other data - ex. (rules or constraints,data definitions and structures) CASE - a class of tools that automates the design of databases and application programs. Insertion anomaly - when certain attributes cannot be inserted into the database without the presence of other attributes Insertion
Insert Anomaly **True/False1. Metadata are data that describe the properties of other data - True 2. Redundancy increases the risk of inconsistent data - True 3. Cost and complexity are just two of the disadvantages of database processing - True 4. In an E-R diagram, strong entities are represented by double-walled rectangles - False 5. In an E-R diagram, an associative entity is represented by a rounded rectangle - True 6. A single occurrence of an entity is called an entity instance - True |
True/False7. An entity type name should always be a singular noun - True 8. A multivalued attribute may take on more than one value for a particular entity instance - True 9. A cardinality constraint tells what kinds of properties are associated with an entity - False 10. A member of a subtype does NOT necessarily have to be a member of the supertype - False 11. There are three separate discriminators in the following diagram because of the overlap rule - True Deletion Anomaly
Deletion True/False13. A composite key consists of only one attribute - False 14. A primary key is an attribute that uniquely identifies each row in a relation - True 15. The following figure is an example of total specialization - False 16. A foreign key is a primary key of a relation that also is a primary key in another relation - False 17. One property of a relation is that each attribute within a relation has a unique name - True Definitions 3Deletion anomaly - exists when certain attributes are lost because of the deletion of other attributes When a regular entity type contains a multivalued attribute, one must - create two new relations, one containing the multivalued attribute Transitive Dependency - A functional dependency between two or more non-key attributes Total Specialization - specifies that for each entity instance of the supertype must be a member of some subtype in the relationship True/False18. There can be multivalued attributes in a relation - False 19. Unlike columns, the rows of a relation may not be interchanged and must be stored in one sequence - False 20. The allowable range of values for a given attribute is part of the domain constraint - True 21. A cascading delete removes all records in other tables associated with the record to be deleted - True 22. When transforming a one-to-one relationship, a new relation is always created - False |
Modification Anomaly
Mod Transitive Specialization
Trans Partial Specialization
Part Spec Total Specialization
Total Misc
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