Chapter 2 Fundamentals of DB Systems
Final Exam And Complete Updated
Answers.
Database abstraction - Answer Generally refers to the suppression of details of the organization and
storage, and the highlighting of the central features for an improved understanding of data
Data model - Answer A collection of concepts that can be used to describe the structure of the
database - provides the necessary means to achieve this abstraction
Dynamic aspect or behavior - Answer Allows the database designer to specify a set of valid user
defined operations that are allowed on the database objects
High-level conceptual - Answer Concepts that are close to the way many users perceived data
Low-level/physical data models - Answer Concepts that describe the details of how data is stored on
the computer storage media, typically magnetic desks
Representational/implementation data models - Answer Concepts that may be easily understood by
end-users but that are not too far removed from the way it is organized in computer storage
Entity - Answer A real world object or concept from the mini world
Attribute - Answer Some property of interest that describes an entity, such as the employees name or
salary
Entity-relationship - Answer A popular high-level conceptual data model
Object data - Answer A new family of higher-level implementation data models that are closer to
conceptual data models
, Access path - Answer A search structure that makes the search for particular database records efficient,
such as indexing or hashing
Index - Answer An access path that has direct access to data using an index term or a keyword.
Self describing data models - Answer Another class of data models where the description of the data is
combined with the data values themselves. These models include XML as well as many of the key value
stores and NOSQL systems
Database schema (sometimes called the intension) - Answer The description of the database
Schema diagram - Answer a displayed schema
Schema construct - Answer Each object of the schema.
Database state or Snapshot (also called an extension of the schema) - Answer The data in the database
at a particular moment in time. Also called the current set of occurrences or instances in the database
Meta-data - Answer The descriptions of the schema constructs and constraints in the DBMS catalog
Defining a new db - Answer specifying the db schema only to the DBMS
initial state - Answer the db state when the db is first populated or loaded.
valid state - Answer a state of the db that satisfies the structure and constraints specified in the
schema.
three-schema architecture - Answer 1) the internal level has an internal schema, which describes the
physical stored structure of the database. The internal schema uses a physical data model and describes
the complete details of data storage and excess paths for the database.
2). The conceptual level has a conceptual schema, which describes the structure of the whole database
for a community of users. 3). The external or view level includes a number of external schemas or user
Final Exam And Complete Updated
Answers.
Database abstraction - Answer Generally refers to the suppression of details of the organization and
storage, and the highlighting of the central features for an improved understanding of data
Data model - Answer A collection of concepts that can be used to describe the structure of the
database - provides the necessary means to achieve this abstraction
Dynamic aspect or behavior - Answer Allows the database designer to specify a set of valid user
defined operations that are allowed on the database objects
High-level conceptual - Answer Concepts that are close to the way many users perceived data
Low-level/physical data models - Answer Concepts that describe the details of how data is stored on
the computer storage media, typically magnetic desks
Representational/implementation data models - Answer Concepts that may be easily understood by
end-users but that are not too far removed from the way it is organized in computer storage
Entity - Answer A real world object or concept from the mini world
Attribute - Answer Some property of interest that describes an entity, such as the employees name or
salary
Entity-relationship - Answer A popular high-level conceptual data model
Object data - Answer A new family of higher-level implementation data models that are closer to
conceptual data models
, Access path - Answer A search structure that makes the search for particular database records efficient,
such as indexing or hashing
Index - Answer An access path that has direct access to data using an index term or a keyword.
Self describing data models - Answer Another class of data models where the description of the data is
combined with the data values themselves. These models include XML as well as many of the key value
stores and NOSQL systems
Database schema (sometimes called the intension) - Answer The description of the database
Schema diagram - Answer a displayed schema
Schema construct - Answer Each object of the schema.
Database state or Snapshot (also called an extension of the schema) - Answer The data in the database
at a particular moment in time. Also called the current set of occurrences or instances in the database
Meta-data - Answer The descriptions of the schema constructs and constraints in the DBMS catalog
Defining a new db - Answer specifying the db schema only to the DBMS
initial state - Answer the db state when the db is first populated or loaded.
valid state - Answer a state of the db that satisfies the structure and constraints specified in the
schema.
three-schema architecture - Answer 1) the internal level has an internal schema, which describes the
physical stored structure of the database. The internal schema uses a physical data model and describes
the complete details of data storage and excess paths for the database.
2). The conceptual level has a conceptual schema, which describes the structure of the whole database
for a community of users. 3). The external or view level includes a number of external schemas or user
