D426 Data Management - Foundations
Data ANS: is numeric, textual, visual, or audio information that describes real-world systems. Data is
collected and processed to aid in a variety of tasks, such as forecasting weather, analyzing financial
investments, and tracking the global spread of pandemics
Data can vary in several important ways: ANS: *Scope. The amount of data produced and collected can
vary. Ex: A small business might track an inventory of a few thousand items, but a large commerce
website might track billions of items.
*Format. Data may be produced as numbers, text, images, audio, or video. Ex: A phone's proximity
sensor generates raw numbers, and a satellite captures images.
*Access. Some data sources are private while others are made publicly available. Ex: A retail company
may use private customer data to discover purchasing behavior patterns, but a government may be
required by law to share certain data sets
analog and digital ANS: Historically, data was mostly analog, encoded as continuous variations on
various physical media. Ex: Audio was recorded as vibrations impressed on vinyl disks. Images were
recorded as chemicals on celluloid tapes. Today, data is mostly digital, encoded as zeros and ones on
electronic and magnetic media.
Examples of public data sets. ANS: 1) Data.gov provides thousands of U.S. government data sets.
Precipitation data can be used to visualize rainfall intensity.
2) Kaggle.com allows users to find and publish data sets. The Financial Tweet data set can show who
tweets on similar topics.
3) data.Nasa.gov provides data sets in aerospace and other related sciences. A data set of light
measurements describes astronomical phenomena.
visualization ANS: Data relationships are often represented in a graphical format, called a visualization,
such as the images in the animation above
drag the website name below to the matching description ANS:
,database ANS: A database is a collection of data in a structured format. In principle, databases can be
stored on paper or even clay tablets. In practice, however, modern databases are invariably stored on
computers. The database structure ensures that similar data is stored in a standardized manner
Consequently, databases must be managed with sophisticated software tools: ANS: *database
management system: is software that reads and writes data in a database
*A query: is a request to retrieve or change data in a database.
*A database application: is software that helps business users interact with database systems.
Database software is organized in layers ANS: Database software is organized in layers. Applications
interact with a query language on one layer, and a query language interacts with a database system on
another layer. Other software layers, such as the operating system, are beyond the scope of this
material.
An information management system ANS: An information management system is a software application
that manages corporate data for a specific business function. An information management system
usually includes a database system as well as other components, such as a user interface, business logic,
and interfaces to other systems.
A bank database ANS: 1)Banking data is stored in a database and is managed by a database system.
2) A bank customer uses an application to perform bank transactions.
3) Banking transactions cause the database system to modify the bank's database and update the user's
account.
Databases.
Refer to the animation above. ANS:
People interact with databases in a variety of roles ANS: * A database administrator is responsible for
securing the database system against unauthorized users.
* A database designer determines the format of each data element and the overall database structure
,* A database user is a consumer of data in a database
Database roles. ANS: 1) The database designer establishes the structure of the database and
determines the data to be collected and stored.
2) The database administrator ensures the database is available and secure.
3) A database programmer uses query languages and programming languages to develop applications
for database users.
4) Database users are the primary consumers of database data through applications and query
languages.
Roles ANS:
text file or spreadsheet ANS: Small databases that are shared by one or two users can be managed in a
text file or spreadsheet.
Large, complex databases that are shared by many users have special requirements: ANS:
*Performance. When many users and applications simultaneously access large databases, query
response time degrades rapidly. Database systems maintain fast response times by structuring data
properly on storage media and processing queries efficiently.
*Authorization. Many database users should have limited access to specific tables, columns, or rows of a
database. Database systems authorize individual users to access specific data.
*Security. Database systems ensure authorized users only access permissible data. Database systems
also protect against hackers by encrypting data and restricting access.
*Rules. Database systems ensure data is consistent with structural and business rules. Ex: When
multiple copies of data are stored in different locations, copies must be synchronized as data is updated.
Ex: When a course number appears in a student registration record, the course must exist in the course
catalog.
*Recovery. Computers, database systems, and individual transactions occasionally fail. Database
systems must recover from failures and restore the database to a consistent state without loss of data.
, Limitations of file systems. ANS: 1) A list of bank transactions is stored in the text file bookkeeping.txt.
Each persons' transactions include a date, type, and the amount of money paid or received.
2) Two programs access the text file. One adds new transactions, and the other calculates account
balances.
3) When program A writes transactions quickly to the file, Program B misses the $4000 deposit and
calculates Raul's balance incorrectly.
4) Program A may write an erroneous transaction.
5) A lack of adequate security could allow unauthorized users to access the file.
Limitations of file systems.
Refer to the animation above ANS:
A transaction ANS: A transaction is a group of queries that must be either completed or rejected as a
whole. Execution of some, but not all, queries results in inconsistent or incorrect data. Ex: A debit-credit
transaction transfers funds from one bank account to another. The first query removes $100 from one
account and the second query deposits $100 in another account. If the first query succeeds but the
second fails, $100 is mysteriously lost. The transaction must process either both queries or neither
query.
When processing transactions, database systems must: ANS: *Ensure transactions are processed
completely or not at all. A computer or application might fail while processing a transaction. When
failing to process a transaction, the database system must reverse partial results and restore the
database to the values prior to the transaction.
*Prevent conflicts between concurrent transactions. When multiple transactions access the same data
at the same time, a conflict may occur. Ex: Sam selects a seat on a flight. Maria purchases the same seat
in a separate transaction before Sam completes his transaction. When Sam clicks the 'purchase' button,
his seat is suddenly unavailable.
*Ensure transaction results are never lost. Once a transaction completes, transaction results must
always be saved on storage media, regardless of application or computer failures.
Transactions. ANS: 1) Two programs access a bank database. The database tracks customer deposits,
credits, and account balances.
Data ANS: is numeric, textual, visual, or audio information that describes real-world systems. Data is
collected and processed to aid in a variety of tasks, such as forecasting weather, analyzing financial
investments, and tracking the global spread of pandemics
Data can vary in several important ways: ANS: *Scope. The amount of data produced and collected can
vary. Ex: A small business might track an inventory of a few thousand items, but a large commerce
website might track billions of items.
*Format. Data may be produced as numbers, text, images, audio, or video. Ex: A phone's proximity
sensor generates raw numbers, and a satellite captures images.
*Access. Some data sources are private while others are made publicly available. Ex: A retail company
may use private customer data to discover purchasing behavior patterns, but a government may be
required by law to share certain data sets
analog and digital ANS: Historically, data was mostly analog, encoded as continuous variations on
various physical media. Ex: Audio was recorded as vibrations impressed on vinyl disks. Images were
recorded as chemicals on celluloid tapes. Today, data is mostly digital, encoded as zeros and ones on
electronic and magnetic media.
Examples of public data sets. ANS: 1) Data.gov provides thousands of U.S. government data sets.
Precipitation data can be used to visualize rainfall intensity.
2) Kaggle.com allows users to find and publish data sets. The Financial Tweet data set can show who
tweets on similar topics.
3) data.Nasa.gov provides data sets in aerospace and other related sciences. A data set of light
measurements describes astronomical phenomena.
visualization ANS: Data relationships are often represented in a graphical format, called a visualization,
such as the images in the animation above
drag the website name below to the matching description ANS:
,database ANS: A database is a collection of data in a structured format. In principle, databases can be
stored on paper or even clay tablets. In practice, however, modern databases are invariably stored on
computers. The database structure ensures that similar data is stored in a standardized manner
Consequently, databases must be managed with sophisticated software tools: ANS: *database
management system: is software that reads and writes data in a database
*A query: is a request to retrieve or change data in a database.
*A database application: is software that helps business users interact with database systems.
Database software is organized in layers ANS: Database software is organized in layers. Applications
interact with a query language on one layer, and a query language interacts with a database system on
another layer. Other software layers, such as the operating system, are beyond the scope of this
material.
An information management system ANS: An information management system is a software application
that manages corporate data for a specific business function. An information management system
usually includes a database system as well as other components, such as a user interface, business logic,
and interfaces to other systems.
A bank database ANS: 1)Banking data is stored in a database and is managed by a database system.
2) A bank customer uses an application to perform bank transactions.
3) Banking transactions cause the database system to modify the bank's database and update the user's
account.
Databases.
Refer to the animation above. ANS:
People interact with databases in a variety of roles ANS: * A database administrator is responsible for
securing the database system against unauthorized users.
* A database designer determines the format of each data element and the overall database structure
,* A database user is a consumer of data in a database
Database roles. ANS: 1) The database designer establishes the structure of the database and
determines the data to be collected and stored.
2) The database administrator ensures the database is available and secure.
3) A database programmer uses query languages and programming languages to develop applications
for database users.
4) Database users are the primary consumers of database data through applications and query
languages.
Roles ANS:
text file or spreadsheet ANS: Small databases that are shared by one or two users can be managed in a
text file or spreadsheet.
Large, complex databases that are shared by many users have special requirements: ANS:
*Performance. When many users and applications simultaneously access large databases, query
response time degrades rapidly. Database systems maintain fast response times by structuring data
properly on storage media and processing queries efficiently.
*Authorization. Many database users should have limited access to specific tables, columns, or rows of a
database. Database systems authorize individual users to access specific data.
*Security. Database systems ensure authorized users only access permissible data. Database systems
also protect against hackers by encrypting data and restricting access.
*Rules. Database systems ensure data is consistent with structural and business rules. Ex: When
multiple copies of data are stored in different locations, copies must be synchronized as data is updated.
Ex: When a course number appears in a student registration record, the course must exist in the course
catalog.
*Recovery. Computers, database systems, and individual transactions occasionally fail. Database
systems must recover from failures and restore the database to a consistent state without loss of data.
, Limitations of file systems. ANS: 1) A list of bank transactions is stored in the text file bookkeeping.txt.
Each persons' transactions include a date, type, and the amount of money paid or received.
2) Two programs access the text file. One adds new transactions, and the other calculates account
balances.
3) When program A writes transactions quickly to the file, Program B misses the $4000 deposit and
calculates Raul's balance incorrectly.
4) Program A may write an erroneous transaction.
5) A lack of adequate security could allow unauthorized users to access the file.
Limitations of file systems.
Refer to the animation above ANS:
A transaction ANS: A transaction is a group of queries that must be either completed or rejected as a
whole. Execution of some, but not all, queries results in inconsistent or incorrect data. Ex: A debit-credit
transaction transfers funds from one bank account to another. The first query removes $100 from one
account and the second query deposits $100 in another account. If the first query succeeds but the
second fails, $100 is mysteriously lost. The transaction must process either both queries or neither
query.
When processing transactions, database systems must: ANS: *Ensure transactions are processed
completely or not at all. A computer or application might fail while processing a transaction. When
failing to process a transaction, the database system must reverse partial results and restore the
database to the values prior to the transaction.
*Prevent conflicts between concurrent transactions. When multiple transactions access the same data
at the same time, a conflict may occur. Ex: Sam selects a seat on a flight. Maria purchases the same seat
in a separate transaction before Sam completes his transaction. When Sam clicks the 'purchase' button,
his seat is suddenly unavailable.
*Ensure transaction results are never lost. Once a transaction completes, transaction results must
always be saved on storage media, regardless of application or computer failures.
Transactions. ANS: 1) Two programs access a bank database. The database tracks customer deposits,
credits, and account balances.
