Chpt 9

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Questions and Answers

What is the primary function of DAM classes within an RDBMS context?

To connect the core business logic with the database while maintaining modularity. (correct)

To manage user authentication and authorization processes.

To directly handle user interface elements.

To execute complex business logic without interacting with any data.

How do DAM classes typically relate to problem domain classes?

DAM classes are entirely separate from problem domain classes and serve different purposes.

One DAM class is created for every different database used.

There are multiple DAM classes for each problem domain class for efficiency.

Each problem domain class usually corresponds to a single DAM class. (correct)

What action does the Patient-DAM class perform regarding patient data?

It directly manipulates the Patient database without any checks.

It primarily handles business logic calculations related to patient information.

It stores Patient object data in the Patient table and retrieves data to create Patient objects. (correct)

It fetches data and converts it to a Patient object while ignoring database structure.

What advantage does using DAM classes provide when switching databases?

Only the DAM class needs to be updated, not the problem domain class. Signup and view all the answers

What role does the DAM class play in the interaction between the application and the database?

It simplifies interactions by translating between the application logic and the database schema. Signup and view all the answers

What is the primary purpose of object persistence in applications?

To ensure data retains after the application process ends Signup and view all the answers

Which of the following systems uses a database design to avoid data redundancy?

Danica’s Auto Shop Signup and view all the answers

What is a disadvantage of using file-oriented systems for data management?

They can lead to data errors due to redundancy Signup and view all the answers

Which of the following is NOT a function of a Database Management System (DBMS)?

Performing arithmetic calculations Signup and view all the answers

How do databases facilitate complex querying?

Through structured relationships between data entities Signup and view all the answers

What is the role of a DBMS in data manipulation?

To allow users to add, update, manage, and analyze data Signup and view all the answers

Which of the following would be considered a file-oriented system?

Flat file storage Signup and view all the answers

What advantage do databases have over file storage systems?

Ability to manage structured collections of data Signup and view all the answers

What is the primary function of a primary key in a relational database?

To provide unique identification for each row in a table Signup and view all the answers

Which of the following statements best describes referential integrity in RDBMS?

It ensures linked tables maintain valid synchronized values. Signup and view all the answers

What does mapping a problem domain class to a database facilitate?

It maintains logical relationships between classes and stored data. Signup and view all the answers

In terms of scalability, which of the following advantages does RDBMS offer?

It can be expanded or downsized as needed. Signup and view all the answers

How does concurrent access benefit users of a relational database?

It allows multiple users to modify the data simultaneously. Signup and view all the answers

Which rule states that attributes of a concrete class correspond to columns in a table?

Rule 2 Signup and view all the answers

What advantage does maintaining relationship through mapping provide?

Improves efficiency in data access and management. Signup and view all the answers

Which type of database allows for storing data in non-tabular formats?

NoSQL Data Stores Signup and view all the answers

What should be done with multivalued attributes, such as multiple insurance providers for a patient?

Create an associative table linking the patient to the insurance providers. Signup and view all the answers

How should a one-to-one relationship be represented in an RDBMS?

Using an Object ID as a foreign key in one of the tables. Signup and view all the answers

When mapping multivalued aggregation relationships, what is the recommended approach?

Use a new associative table containing foreign keys from both tables. Signup and view all the answers

What needs to be ensured for subclass keys and superclass keys in inheritance?

Subclass keys must match superclass keys when stored. Signup and view all the answers

In a patient-to-appointment relationship, how is a many-to-one relationship typically represented?

By including a patient ID in the Appointment table. Signup and view all the answers

Which rule specifies that methods should be implemented as stored procedures?

Rule 3 Signup and view all the answers

What is the purpose of flattening a hierarchy in RDBMS design?

To simplify the structure by copying superclass attributes. Signup and view all the answers

What should be done with repeating groups when mapping to an RDBMS?

Create a new table to store each repeating group. Signup and view all the answers

Study Notes

Data Management Layer Design

Data is crucial for application functionality
Object persistence is necessary for retaining data after the application closes
Persistence methods include storing data in flat files (sequential or random access), and using Database Management Systems (DBMS) for structured data

Software Development Life Cycle (SDLC)

SDLC is a process for software development
The stages of SDLC are: Idea, Planning, Drawing Analysis, Blueprint Development, and Construction Implementation
The blueprint development stage is related to the design and creation of the desired software's architecture

Selecting Storage Format

Choosing the appropriate storage format for data is important
Files can be stored sequentially or randomly accessed

Object Persistence Formats

Object persistence means objects can exist outside the application's runtime
Common methods include using files (flat files that can be sequential or random access).
- Utilizing a Database Management System (DBMS) to manage structured data collections

Files vs. Databases

File-oriented systems can cause data duplication and errors, particularly in complex systems
Database design avoids duplication; data can be viewed as a single table regardless of physical storage

Database Management Systems (DBMS)

A database is a collection of information groupings that are interconnected
Logical groupings can include categories like customer data, orders, and products
A DBMS is a software that creates and manipulates databases
Example DBMSs include MS Access, MySQL, Oracle, DB2, MS SQL, and NoSQL

Advantages of DBMS

Scalability: The system can be expanded or reduced
Economies of scale: Allows for high-volume data processing while using resources efficiently
Improved security: Only authorized users can access the database
Enterprise-wide applications: Different users have varying access levels
Concurrent access: Multiple users or systems can access and modify data simultaneously

Relational Databases

Relational databases are collections of tables
Each table has a primary key, unique for each row, used to relate tables to each other by creating foreign keys in related tables
Relational Database Management Systems (RDBMS) support referential integrity; maintaining data consistency in linked tables

Types of Databases

Relational Databases (RDBMS)
Object-Relational Databases (ORDBMS)
Object-Oriented Databases (OODBMS)
NoSQL Data Stores

Mapping Problem Domain Classes to Object Persistence Format

Mapping connects design elements (classes, attributes) to database representation
This creates a translation guide to ensure accurate representation in the database (tables, objects)

Mapping Problem Domain to Data

Mapping ensures the connection between design elements (classes, attributes) and how they are stored in the database
This connection maintains relationships, improves efficiency, supports scalability and maintainability, and promotes reuse and flexibility

Mapping to RDBMS

Concrete Classes mapped to Tables: The Patient class maps to the Patient table.
Attributes mapped to Columns: Attributes of a class become columns in the table. For example, Patient attributes like insurance carriers become columns in the Patient table.
Implementing methods as stored procedures
Relationships mapped to columns: Single-valued aggregation or relationships map to a table column where the related table’s key is stored, introducing foreign keys.
Multi-valued attributes: Store multiple values in a column or create a separate table.
Multi-valued aggregation/relationships: Create an associative table relating original tables with foreign keys from both

Data Access and Manipulation (DAM) classes

DAM classes act as an intermediary layer between core classes (business logic) and databases (object persistence)
DAM classes allow applications to interact with databases without direct core logic connection, making design modular and flexible.

DAM Classes (Translator Role)

DAM classes act as translators between the problem domain classes and the database
They handle data reading, writing, saving, retrieving, and updating
Each problem domain class corresponds to a DAM class

Example of a DAM Class (Patient-DAM)

Patient-DAM class handles tasks: writing to/reading from the Patient table, and converting between the Patient object and the database table
It fetches data from the table and creates a Patient object, allowing separation of core logic from database interactions

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Description

This quiz covers essential concepts related to data management layer design and the software development life cycle (SDLC). It discusses the importance of data persistence, various storage formats, and the stages of SDLC, including blueprint development. Test your knowledge on choosing appropriate storage methods and understanding the software development process.