Select all that are TRUE about Databases
Shared collection of logically related data (and a description of this data), designed to meet the information needs of an organization
Shared collection: can be used simultaneously by many departments and users
Logically related: comprises the important objects and the relationships between these objects.
A DBMS is a software system that enables users to define, create, and maintain the database and that provides controlled access to this database?
A 'Database Application Program' is a software program that interacts with the database by issuing an appropriate request (typically an SQL statement) to the DBMS.
What are 'Views'?
Allows each user to connect to the network
Allows each user to have his or her own view of the database
Allows each user to connect to the database
Select ALL that are TRUE about 'Views'
Provide a level of security
Provide a mechanism to customize the appearance of the database
Provide the benefit of regular database backups
Present a consistent, unchanging picture of the structure of the database, even if the underlying database is changed.
What are components of a DBMS Environment?
ACARS Monitoring
Hardware and Software
Data
Procedures
People
What are true about a Two-Tier Client-Server?
Client manages main business and data processing logic and user interface
Server manages and controls access to database
Third Party manage server
What are true about Three-Tier Architecture?
Business logic and data processing layer, middle tier runs on a server (application server)
User interface layer runs on client
Makes use of the Cloud
DBMS stores data required by the middle tier. This tier may be on a separate server (database server)
What are the advantages of the Three-Tier Architecture?
Application maintenance centralized
‘Thin’ client, requiring less expensive hardware
Easier to modify or replace one tier without affecting others
Backups are always and only run off site for redundancy
Maps quite naturally to Web environment
Separating business logic from database functions makes it easier to implement load balancing
Select ALL that are True about Functions of a DBMS
A User-Accessible Catalog
Data Storage, Retrieval, and Update
Concurrency Control Services
Recovery Services
Transaction Support
Integrity Services
Utility Services
Services to Promote Data Independence
Support for Data Communication
Authorization Services
What is NOT an advantage of DBMS
Improved data integrity
Sharing of data
Data consistency
Control of data redundancy
Limited to one Super Administator
Improved maintenance through data independence
What is NOT an disadvantage of DBMS
Cost of conversion
Cost of DBMS
Complexity
Performance
Higher impact of a failure
Intuitive and easy to setup
A Data Model is a Integrated collection of concepts for describing data, relationships between data, and constraints on the data. What are the three components?
a structural part
a manipulative part
a set of integrity rules
Which Relational Model Terminologies are correct?
Relation: table with columns and rows
Attribute: named column of a relation
Domain: set of allowable values for one or more attributes
Tuple: a record of a relation
Relational Database - collection of normalized relations with distinct relation names
Each Table and Column name should be distinct?
A Superkey is a column, or a set of columns, that uniquely identifies a record within a table.
A Candidate Key is the Maximum type of Superkey
Select ALL Relational Key that are correct
Primary Key: Candidate key selected to identify records uniquely within table
Alternate Keys: Candidate keys that are not selected to be primary key
Master Key: Candidate keys that are equivalent to the Primary Key
Foreign Key: Column, or set of columns, within one table that matches candidate key of some (possibly same) table
Select ALL that are True regarding Relational Integrity
Entity Integrity: In a base table, no column of a primary key can be null
Referential Integrity: If FK exists in a table, either FK value must match a candidate key value of some record in its home table or FK value must be wholly null
Relational Integrity: If FK exists in a table, either FK value must match a candidate key value of some record in its home table or FK value must be wholly null
Null Value: Represents value for a column that is currently unknown or not applicable for record
The two main Relational Languages are Structured Query Language and Query-by-Example?
