DS 220 Exam 1
In general, a student at Penn State doesn't have to complete an undergraduate thesis before graduation, although some do (and some are required to). So in general, for a student at Penn State, the minimum cardinality for completing a thesis is (for the relationship type: students completing theses):
0
XML database
A database system that stores and manages semistructured XML data.
Which statement about relational models is correct?
A foreign key CAN be NULL.
Relationship type
A meaningful association between (or among) entity types.
partial participation
a situation in which some entities may not participate in the relationship. (minimum cardinality has 0)
Disjoint Specialization
a specialization where an entity can be a member of at most one of the subclasses
overlap specialization
a specialization where the same entity may be a member of more than one subclass.
n-tier DBMS architecture
a straightforward extension of the client-server architecture.
client-server DBMS
active clients request services from passive servers
Key attribute
an attribute type whose values are distinct for each individual entity.
Interactive queries
are typically executed from a front-end tool, such as a command-line interface, simple graphical user interface, or forms-based interface
Consistency
assures that a transaction brings the database from one consistent state to another
The one-to-many (1:M) relationship is easily implemented in the relational model by putting the foreign key of the "1" side in the table of the "many" side as a primary key.
false
Online Transaction Processing (OLTP)
focus on managing operational or transactional data
Online Analytical Processing (OLAP)
focus on using operational data for tactical or strategical decision-making.
A database contains the following entities: raisins hot dog salad pizza white flour Choose the best example of the entity type that these represent.
foods
If an attribute types, B, is functionally dependent on an attribute type A ( A -> B), then:
A value of A uniquely determines the value of B
Which of the following statements is correct?
A weak entity type is always existence-dependent
Centralized DBMSs Architecture
All DBMS functionality, application program execution, and user interface processing carried out on one machine
Statement A: An OLTP system is able to cope with real-time, simultaneous transactions which the database server is able to process in a huge volume. Statement B: An OLAP system uses large amounts of operational data to run complex queries on and provide insights for tactical and strategical decision making. Which statement(s) is/are correct?
Both A&B
The LionPath course registration database that must constantly update course rosters and student schedules is considered what category of database:
An Online Transaction Processing (OLTP) system
embedded DML statements.
Applications interact with the DBMS
In the context of databases, ACID stands for:
Atomicity Consistency Isolation Durability
Which of the following would be most likely an atomic(simple) attribute type?
Course grade
Data Definition Language
DDL Used by DBA to express the database's external, logical, and internal data models.
data manipulation language
DML used to retrieve, insert, delete, and modify data.
A key difference between databases and a file-based approach to storing data is:
Databases store metadata in the database
An employee database is maintained for a company. The following describes one of the tables: Employee(EmployeeID, Name, Department, Start date, Social Security number) Which of the following is true?
Department is functionally dependent on employeeID
Which of the following is true about Enhanced Entity Relationship (EER) models?
EERs were designed to handle some limitations of the basic ER model
An entity relationship (EER) model can be mapped to a relational data model but to no other types of logical data models.
False
The entity relationship (ER) model is dependent on the database type.
False
LionPath provides a single uniform interface to a number of underlying data sources (such as billing, classroom scheduling, student records). As such, we could categorize LionPath as a:
Federated DBMS
Which statement is CORRECT?
In case a ternary relationship type is represented as 3 binary relationship types, then semantics will get lost.
A database that is classified as a NoSQL database:
Is an umbrella term used to categorize a number of data tools designed for storing big and unstructured data
Which of the following relations is in 1st Normal Form (1NF)?
Pilot(PilotID, Name, Date of Birth, Gender)
Network DBMS
Similar to the hierarchical DBMS, but it lets a child have more than one parent. This can become complicated.
Why is concurrency control an important concept in a DBMS?
Sometimes to different queries will be trying to operate on the same data at the same time
Which of the following is an advantage of UML class diagrams for data modeling that is not possible with EER diagrams?
The UML diagram can define methods
EER modeling is like ER modeling but it also includes the following features that are NOT part of ER modeling:
The new semantic modeling concepts of specialization and categorization
semi-structured data
These are data that have a certain structure, but the structure may be very irregular or highly volatile
In a relational data model, what is the function of keys?
To uniquely identify tuples and help establish relationships
A relationship type can exist between more than two entity types.
True
Databases may be categorized by:
Type of use Data models Number of users permitted
Consider a data model for the Olympics storing information about countries and athletes. There is a 1-N relationship type between country and athlete and an athlete always has to belong to exactly 1 country. A relational data model containing only 1 table leads to:
Unnecessary replication of data about countries.
Which of the Following is not a component of the Three-Layer architecture
View layer
Conceptual Data Model
a high-level description of data items, characteristics, and relationships. Used for communication between information architect and business user to ensure data requirements are properly captured and modeled.
A strong entity type has:
a key attribute type
A logical data model
a mapping of relationships to a specific type of DBMS
federated dbms
a DBMS that provides a uniform interface to multiple underlying data sources such as other DBMSs, file systems, document management systems, etc.
ER Model
a data model that shows the relationship among data items through entity types, attribute types, and relationship types. Visualized through an attractive and user-friendly graphical notation.
Object-Oriented DBMS
based upon the object-oriented data model. An object encapsulates both data (also called variables) and functionality (also called methods).
A relationship type that involves two entity types is known as a
binary relationship type
A key attribute type_________________.
can uniquely identify an entity
atomic attribute type
cannot be further divided into pats
A database that uses SQL for both the DDL and the DML is typically:
categorized based on a relational data model
Data independence
changes in data definitions have minimal to no impact on the applications using the data. Occur in the conceptual layer
DDL compiler
compiles the data definitions specified in DDL. Ideally, the DBMS should provide three DDLs: one for the internal data model; one for the logical data model; and one for the external data model
DML compiler
compiles the data manipulation statements specified in DML
In the database design, one starts from a business process. The first step is to gather and analyze requirements from the customer to come up with a list of requirements. This is then used in _____________________, the 2nd step in the database design process.
conceptual data modeling
The entity relationship diagram is used for:
conceptual data modeling
An EER model is a _____________ data model that can be mapped to several different types of ___________ data models, one of which is the relational data model.
conceptual, logical
temporal constraint
constraints spanning a particular time interval, cannot be modeled.
DDL statements
create data definitions that are stored in the catelog
A database model which provides a description of the database data and provides specifics on various data items is also called a :
database schema
The two types of constraints that can be placed on specializations are:
disjointness and completeness
In the standard Chen notation for entity-relationship modeling, an attribute type is represented by a:
ellipse/oval
Durability
ensures that the database changes made by a transaction declared successful can be made permanent under all circumstances
Isolation
ensures that the effect of concurrent transactions should be the same as if they had been executed in isolation
procedural DML
explicitly specified how to navigate in the database to locate and modify the data
If some users can see a students courses only and other users can see the student's courses and grades, this is an example of different:
external layer views
Physical Data Independence
implies that neither the applications, views, or logical data model must be changed when changes are made to the data storage specifications in the internal data mode
Logical Data Independence
implies that software applications are minimally affected by changes in the conceptual or logical data model
EER Model
includes all the modeling concepts) of the ER model, as well as three new additional semantic data modeling concepts: specialization/generalization, categorization, and aggregation.
total participation
minimum cardinality is 1
Degree of a relationship type
number of participating entity types
A conceptual data model, a first step in developing a good database application,
provides a way depict the business needs and the information architecture that will be required
specialization
refers to the process of defining a set of subclasses of an entity type A singer is an artist but not the other way around
In a relational model, an entity type is called a:
relation
entity type
represents a business concept with an unambiguous meaning to a particular set of users
attribute type
represents a property of an entity type
composite attribute type
s an attribute type that can be decomposed into other meaningful attribute types
Hierarchial DBMS
were one of the first DBMS types developed, and adopt a tree-like data model. No query processor
NoSQL DBMS
software products that support very high transaction rates, processing relatively simple data structures, replicated on many servers in the cloud
domain
specifies the set of values that may be assigned to an attribute for each individual entity
disjointness constraint
specifies what subclasses an entity of the superclass can belong to. It can be set to either disjoint or overlap
Data Manipulation Languages (DML) can be categorized as procedural or declarative. The difference is that declarative DMLs:
specify only which data the user wants and leaves the details of how to find it up to the DBMS
Cardinalities
specify the minimum or maximum number of relationship instances that an individual entity can participate in
Declaritive DML
statements specify which data should be retrieved or what changes should be made, rather than how this should be done
in-memory dbms
stores all data in internal memory instead of slower external storage such as disk-based storage
query processor
t assists in the execution of database queries such as retrieval of data, insertion of data, update of data, and removal of data from the database
A relationship type that involves three entity types is known as a
ternary relationship type
cloud dbms architecture
the DBMS and database are hosted by a third-party cloud provider.
Atomicity
the all-or-nothing property, requires that a transaction should either be executed in its entirety or not at all
Open Source DBMS
the code is publicly available and can be extended by anyone.
structured data
the only kind of data the earlier DBMS implementations focused on. individual characteristics of data items can be identified and formally specified, such as the number, name, address, and email of a student, or the number and name of a course
Generalization
the reverse process of specialization. Specialization corresponds to a top-down process of conceptual refinement. Singer and Actor can be generalized in the artist superclass
unstructured data
there are no finer-grain components in a file or series of characters that can be interpreted in a meaningful way by a DBMS or application
Humans can be either vegetarian or non-vegitarian. This is an example of _______________ specialization:
total
Relational DBMS
use the relational data model and are the most popular in the industry. They typically use SQL for both DDL and DML operations.
Object-relational DBMS
uses a relational model extended with object-oriented concepts, such as user-defined types, user-defined functions, collections, inheritance, and behavior
