14% Lesson 1 Introduction to Databases, Information and Data
(7 Questions)
Competency 4017.1.1: Introduction to Information and Data
Explain how data, databases, and data management is used in today's
organization
➢ Explain what data is and how is it stored
➢ Explain the different types of data
➢ Define file structures
➢ Explain how data was stored and retrieved before the use of
database management systems
1.1 Why Databases
• Best way to store and manage data
• Makes data persistent and shareable in a secure way
• Essential for organizations to know information about Customers,
Products, Employees, Debtors / Creditors
• Helps organizations use data / information as a resource to
make decisions
1.2 File Structures
• File-Based (Prior to DBMS)
o Attempt to computerize old manual filing system
o Was easy to retrieve small amounts of information from
o As data grew, it became difficult to locate and retrieve
information
o Retrieval speed depended on file structure and how
data was organized within the structure
• File types utilized in a file-based system
o Flat Files
• No internal hierarchy
• Plain text or Binary files
• Data that is unstructured
• Uses a lot of computer memory to access, edit, and
rewrite files after use
o Heap Files
• Unsorted set of records
• Uniquely identified by record ID
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o Allows Heap file to be inserted or deleted using ID
o Index Files
• File that stores a list of Look Up Field values from data file
that includes the location (address) in the data file of the
corresponding record
• Smaller than the entire record, usually fits in main
memory for quick look up
• Lists keywords and phrases that are in a particular file
• Becomes a pointer to the location in the file where the
information can be found when stored with keywords
and phrases
o Hashed Files
• Uses hash functions to decide where records should be
placed on a disk
• Allows for faster data look up without the use of an index
file
1.3 Data versus Information
• Data
o Data is the Foundation of Information
o Consists of Raw Facts not yet processed to reveal meaning
o Raw facts / data will need to be transformed to better
understand what it is that you have
o Must be properly formatted for storage, processing, and
presentation
• Information
o Information is the Bedrock of Knowledge
o Produced by Processing Raw Data to reveal its meaning
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• Processing may be as simple as organizing it to reveal
patterns or complex as making forecast / drawing
inferences using system statistical modeling
o Key to good decision making and business survival is
accurate, relevant, and timely information
• Knowledge
o Information and facts about a specific subject
o Implies familiarity awareness and understanding of Information
o Key Characteristic is that New Knowledge can be derived from
Old Knowledge
• Data Management
o A discipline that focuses on the proper generation,
storage, and retrieval of data
o Is it core activity for any business, government
agency, service organization, or charity
1.4 Introducing the Database
• Database
o Shared, integrated computer structure that stores:
• End User Data
o Raw facts of interest to the end user
• Metadata (Also called: A collection of Self-Describing Data)
o Data about data through which data is
integrated and managed
o Describes data characteristics and set of
relationships that links data found in the
database
o Stores information like:
• Name of each data element
• Type of values (numeric, dates, or text)
on each data element
• Whether the data element can be left empty
o Complements and expands the value and use of the
data
• Role of the DBMS
o An intermediary between user and database
o Presents the end user with a single integrated view of
data in a database
o Receives all application requests and translates them
into complex operations
o Hides database complexities from the application programs and
users
o Provides a framework facilitate data quality initiatives
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o May be written using Visual Basic, NET, JAVA, C#, or through
a DBMS utility program
• Advantages of a DBMS
o Enables data sharing across multiple applications / users
o Integrates different user views of data into a single repository
o Makes data management more efficient and effective
o Improves Data Sharing
• Creates an environment in which users have better
access two more and better-managed data
o Improves Data Security
• Provides framework for better enforcement of data /
security policies
o Better Data Integration
• Promotes integrated view of operations and the
ability to see data relations or impact actions have in
other areas
o Minimizes Data Inconsistency
• Data Inconsistency exists when different versions of
the same data appear in different places
• Greatly reduced in a properly designed database
o Improves Data Access
• Easier to produce quick answers to a query / ad hoc query
o Query is a specific request / question
o Ad Hoc Query is a “Spur-or-the-Moment” question
o Query Result Set is a collection of data rows
returned by a query
o Improves Decision Making
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