Chapter 8 Flashcards
The way records are physically arranged on the secondary storage device
Organization
Technique used to locate records and to navigate through the database or file
Access Method
All records in contiguous storage spaces in specified sequence
Key Field
Structure that employs algorithm to convert primary key into physical record storage address with no separate index necessary
Hashing Structure
Different keys may create same address
Collision
Stores the address of related record in a field with each data record
Pointers
_______ provide connections between records and may be used to link records between files
Pointers
Contains actual disk storage location which allows direct access to the record
Physical address pointer
An ___________ structure which facilitates direct access to individual records and batch processing of the file
Indexed sequential file
Multiple indexes can create an _________ or cross-reference allowing even more flexible access to data
Inverted list
Represented by a line connecting two entities
Association
The degree of association between two entities
Cardinality
Nature of association between related tables determines method used to assign foreign keys
Foreign key
The set of data a particular user sees
User view
Negative operational symptoms called
Anomalies
To be free of anomalies, tables must be normalized to the
Third normal form (3NF)
The results from data redundancy in an unnormalized table
Update anomaly
Occurs when a new item cannot be added to the table because there is no association with the primary key
Insertion anomaly
Involves unintentional deletion of data. When an attribute item used by only one entity is deleted, all information about that attribute item is lost
Deletion anomaly
The process in normalizing tables that identifies and removes dependencies resulting in tables
Normalization process
