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INFS 768 > Midterm Review > Flashcards

Midterm Review Flashcards

Chapters 1-6, 9 main concepts review

1
Q

What is a database?

A

A database is a shared, integrated computer structure that stores a collection of end-user data and metadata.

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2
Q

Name some advantages of the DBMS over file systems.

A
  • Improved data sharing
  • Improved data security
  • Better data integration
  • Minimized data inconsistency
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3
Q

What are some key problems with using spreadsheets as substitutes for databases?

A
  • Complex system administration
  • Lack of security and limited data sharing
  • Extensive programming required
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4
Q

What were the key problems with file system data processing?

A
  • Structural and data dependence
  • Data redundancy
  • Data anomalies
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5
Q

Why is data redundancy undesirable?

A

It leads to:

  • Poor data security
  • Data inconsistency
  • Data-entry errors
  • Data-integrity problems
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6
Q

What components make up a database system?

A

Hardware, software, people, procedures, and data

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7
Q

What are some disadvantages of database systems?

A
  • Increased costs
  • Management complexity
  • Maintaining currency
  • Vendor dependence
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8
Q

What components does a data model need to be “implementation ready”?

A
  1. A description of data structures that will store end-user data.
  2. Set of enforceable rules to guarantee data integrity.
  3. Data manipulation methodology to support real-world transformations.
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9
Q

What are the basic building blocks of every data model?

A
  1. Entities
  2. Attributes
  3. Relationships
  4. Constraints
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10
Q

What is the main difference between the network and the hierarchical data models?

A

The network model allows a given record to have more than one parent.

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11
Q

What was the key shortcoming of the network model?

A

It lacked ad hoc query abilities and required a large amount of coding even for simple reports.

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12
Q

From the end-user perspective, what three parts does any SQL-based relational database consist of?

A
  1. End-user interface
  2. Tables stored in the database
  3. SQL engine
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13
Q

What describes the main difference between the purposes of an object-oriented data model and a relational database model?

A

The object-oriented data model was created to address very specific engineering needs, while the relational database model was created for data management with a sound mathematical foundation.

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14
Q

What are the main reasons the relational database approach does not always satisfy the needs of organizations dealing with Big Data?

A
  1. The relational database is not designed for handling large amounts of unstructured data.
  2. Adding large amounts of data daily is costly in the relational environment.
  3. Data analysis with OLAP tools is not effective for unstructured data.
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15
Q

What are the four levels of abstraction shown by data models?

A
  1. Internal models
  2. External models
  3. Conceptual models
  4. Physical models
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16
Q

What does “logical independence” mean in the context of data models?

A

It means the internal model can be changed without affecting the conceptual model.

17
Q

What are the three well-defined components of a relational model?

A
  1. A logical data structure represented by relations.
  2. A set of integrity rules.
  3. A set of operations for data manipulation.
18
Q

What are the two requirements for entity integrity?

A
  1. All the values of the primary key must be unique.

2. No key attribute in the primary key can be null.

19
Q

What is the requirement for referential integrity?

A

A foreign key may have either a null entry or an entry that matches the primary key value in a related table.

20
Q

What two conditions define a weak entity?

A
  1. Entity is existence-dependent

2. Entity has a primary key that is partially or totally derived from parent entity.

21
Q

What are the three, sometimes conflicting goals in designing databases?

A
  1. Adherence to design standards
  2. Processing speed
  3. Information requirements
22
Q

What is the main goal of normalization?

A

Eliminate data anomalies by removing unnecessary data redundancies.

23
Q

When is a table in Boyce-Codd Normal Form?

A

When every determinant in the table is a candidate key.

24
Q

What are the five phases of the systems development life cycle?

A
  1. Planning
  2. Analysis
  3. Detailed systems design
  4. Implementation
  5. Maintenance
25
Q

In which phase of the SDLC does data modeling usually take place?

A

Analysis phase

26
Q

What are the main outputs of the logical design step in the SDLC?

A

Functional descriptions of system’s modules and processes.

27
Q

What are the six phases of the database life cycle?

A
  1. Database initial study
  2. Database design
  3. Implementation and loading
  4. Testing and evaluation
  5. Operation
  6. Maintenance and evolution
28
Q

What are the four steps involved in the conceptual design of a database?

A
  1. Data analysis and requirements
  2. ER modeling and normalization
  3. Data model verification
  4. Distributed database design
29
Q

What factors affect an organization’s decision of which DBMS software to select?

A
  • Cost
  • Features and tools
  • Underlying model
  • Portability
  • Hardware requirements
30
Q

What is the goal of the logical design stage of the database design process?

A

Design enterprise-wide database that is based on a specific data model but independent of physical level details.

31
Q

What is the goal of the conceptual design stage of the database design process?

A

Design a database that is independent of database software and physical details.

32
Q

What are the four steps of the logical design stage of the database design process?

A
  1. Map conceptual model to logical model components.
  2. Validate logical model using normalization.
  3. Validate logical model using integrity constraints.
  4. Validate logical model against user requirements.
33
Q

What is the goal of the physical design stage of the database design process?

A

Determining data storage organization and data access characteristics.

34
Q

What are the three steps of the physical design stage of the database design process?

A
  1. Define data storage organization.
  2. Define integrity and security measures.
  3. Define performance measures.

INFS 768 (1 decks)

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