UTA INSY 3304 EXAM QUESTIONS AND ANSWERS
LATEST UPDATE (ALREADY GRADED A+)
Limitations of a file system in data management
- Data dependence
- Structural dependence
- Data redundancy leading to deletion, insertion, and modification anomalies
Components of a DBMS/database Environment
- hardware, software, people, procedure, and data
Data Modeling
is iterative and progressive
Database models
Conceptual and Implementation
Conceptual
The conceptual model provides a global view of an entire database. Describes the main data objects,
avoiding details and define what the relationships are.
entities and relationships, different types of relationships
Implementation
hierarchical, network, relational, Object Oriented
-It does support many to many relationships
Hierarchical
upside down tree structure, 1-M relationship
-easy to understand, but drawbacks: no standards, data dependency
Network-
upside down tree structure, supports M-M relationships
-standards, but data dependency, difficult to implement because of the many to many
Object Oriented
data becomes active component of system using methods and attributes
-You can use these Code reuse, polymorphism, encapsulation in the database
Relational:
still most popular dbms model
, Different levels of data models
Conceptual, Internal, External, Physical
Conceptual Database model
The output of the conceptual design process. The conceptual model provides a global view of an entire
database. Describes the main data objects, avoiding details.
-highest level, contains least detail, not hardware or software dependent.
internal Database model
refers to a level of data abstraction that adapts the conceptual model to a specific DBMS model for
implementation.
-adapt conceptual model to dbms that's chosen.
External Database model
The application programmer's view of the data environment. Given its businessunit focus, an external
model works with a data subset of the global database schema.
-both are software dependent, gives a breakdown of model into functional units
Physical Database model
model in which the physical characteristics (location, path, and format) are described for the data. Both
hardware- and software-dependent.
-mapping out how to get to data, access paths,
Basic concepts about the relational database model
entities, attributes, tables, rows, columns, domain of an attribute, cardinality, connectivity
Entity
person place or thing that you want to store data about (represented as a table or relation)
+represented by rectagle
Attributes
characteristic or property of the data or of the entity, stored as columns
+represented by ovals
+property of an entity and stored in a table
• Row table
instance of an entity each row is an instance
+represent a record in a file
• Column
represent the attribute
+represent a field in a file
LATEST UPDATE (ALREADY GRADED A+)
Limitations of a file system in data management
- Data dependence
- Structural dependence
- Data redundancy leading to deletion, insertion, and modification anomalies
Components of a DBMS/database Environment
- hardware, software, people, procedure, and data
Data Modeling
is iterative and progressive
Database models
Conceptual and Implementation
Conceptual
The conceptual model provides a global view of an entire database. Describes the main data objects,
avoiding details and define what the relationships are.
entities and relationships, different types of relationships
Implementation
hierarchical, network, relational, Object Oriented
-It does support many to many relationships
Hierarchical
upside down tree structure, 1-M relationship
-easy to understand, but drawbacks: no standards, data dependency
Network-
upside down tree structure, supports M-M relationships
-standards, but data dependency, difficult to implement because of the many to many
Object Oriented
data becomes active component of system using methods and attributes
-You can use these Code reuse, polymorphism, encapsulation in the database
Relational:
still most popular dbms model
, Different levels of data models
Conceptual, Internal, External, Physical
Conceptual Database model
The output of the conceptual design process. The conceptual model provides a global view of an entire
database. Describes the main data objects, avoiding details.
-highest level, contains least detail, not hardware or software dependent.
internal Database model
refers to a level of data abstraction that adapts the conceptual model to a specific DBMS model for
implementation.
-adapt conceptual model to dbms that's chosen.
External Database model
The application programmer's view of the data environment. Given its businessunit focus, an external
model works with a data subset of the global database schema.
-both are software dependent, gives a breakdown of model into functional units
Physical Database model
model in which the physical characteristics (location, path, and format) are described for the data. Both
hardware- and software-dependent.
-mapping out how to get to data, access paths,
Basic concepts about the relational database model
entities, attributes, tables, rows, columns, domain of an attribute, cardinality, connectivity
Entity
person place or thing that you want to store data about (represented as a table or relation)
+represented by rectagle
Attributes
characteristic or property of the data or of the entity, stored as columns
+represented by ovals
+property of an entity and stored in a table
• Row table
instance of an entity each row is an instance
+represent a record in a file
• Column
represent the attribute
+represent a field in a file
