Transcript Document

Using Databases to
Facilitate Learning
and Develop Inquiry
Skills
Definitions, Planning and Design Issues,
Higher-Order Thinking Skills,
Advantages and Disadvantages
What Can You Do with a
Database ?
Databases can be used to:
 Analyze, collect, and manipulate data.
 Foster problem-solving activities
(planning, organizing, categorization,
dissemination, and logical thinking).
 Create an environment for inquiry.
 Classify and group data.
Definitions
 A database is a collection of related fields
grouped into records.
 Fields are the smallest unit of data and are
useless by themselves. All fields related to
a particular subject form records.
 Records are used to represent all the
information pertaining to one person,
place, topic, or thing.
 The conglomeration of records forms the
database.
Steps to Complete Before
Planning a Database
Thoroughly understand:
 The data to store and manipulate.
 The interdependencies among data.
 The reason why the data exists.
 The types of problems that can be solved
using the data.
 The ways data can be managed and
manipulated to produce a useable product.
Steps in Planning a
Database
 Decide what data fields are needed now
and project future needs.
 Define data fields and name them
appropriately.
 Establish guidelines for the
contents of each field.
 Enter data.
Planning the Database
Fields contain text or numeric data. In
some databases, they can also contain
pictures, computations, times, or dates.
The definition of fields is a critical part of
planning the database. In order for the
database to be useful, it must have all
information necessary for solving a given
problem (i.e., many useful and relevant
fields).
Planning the Database
 Fields should contain only one type of data
in order to provide uniformity, make the
database easy to use, produce consistent
results from queries, and make the
database more reliable.
 It is best to subdivide fields for accuracy
and ease-of-use. Example: Name (John
Doe) could become Last Name (Doe) and
First Name (John) or Size = 9lbs. 2oz. could
be Pounds (9) Ounces(2).
Planning the Database
Naming fields is also important. Long,
unrelated names should be avoided and
replaced with short, concise, and easily
understood titles.
Examples:
 “City in the USA” = City
 “Things birds eat” = Diet
 “Length of reptile” = Length
Planning the Database
After fields have been selected and
appropriately named, it is essential to analyze
the field’s contents and design applicable
rules or guidelines for data entry.
Without guidelines or predetermined ranges
for data entry, searching and sorting these
fields will produce inconsistent and
inaccurate results.
Some Currently Available
Database Packages
 Dbase
 Oracle
 ClarisWorks
 Microsoft Works for
Windows
 Access
Database Structures
 Hierarchical
 Relational
 Network
Hierarchical Databases
 This is the simplest type of database.
 The tree structure illustrates this concept.
Hierarchical Databases
 Information is accessed from the top to
the bottom (top-down).
 Illustrates a parent-child relationship
where each item relates only to the one
above and below it.
 Disadvantage – following the hierarchy
is sometimes difficult, cumbersome, and
time consuming.
Relational Database
 Allows multiple associations using
common fields in multiple databases.
 Arranged in a two-dimensional table
format.
 Files are known as relations, fields are
columns, and records are called rows.
 Performs the following: joining, projection,
and selection.
Relational Database
 Used in libraries effectively
 Users must define, create, and implement
files. This is not automatically done by the
relational database or database
management system.
 Disadvantage: there is no way to link fields
in a practical manner. Explicit links are
formed by relations (or files rather than
specific fields contained within files).
Network Databases
 These types of databases have a less rigid
structures than the hierarchical model.
They permit the use of pointers to
establish the shortest path to specific
information.
 This model is well suited for
transaction processing like
those found in banking,
inventory control, and airline
reservation systems.
Network Databases
 Good for standardized operations.
 Disadvantage: Complex pointer
implementation makes modification
involved, and requires care to keep
established links from being lost.
 When transactions are not predictable
or stable, a relational database is a
better model.
Products from a Database
After the database has been created and data
entry has taken place, students or users can
produce reports or lists that sort, extract, and
summarize information from the database.
Sort
Arrange in ascending or descending
order.
Extract
Produce a subset from the collection of
information.
Summarize
Total amounts or a count of items
located.
Data Extraction – Arithmetic
and Boolean Operators
=
Equal to
<>
Not equal
>
Greater than
>=
Greater than or equal
<
Less than
<=
Less than or equal
AND
Include all items
OR
Include either item
NOT
Exclude item
Matching Database Functions
with a Learning Task
Modified from (Table 11-1, pp.259) of Morrison and
Lowther’s Integrating Computer Technology into the
Classroom, 2ed.
Learning Task
Database Function
Combine, Match, Sequence
Match and Sort Information
Compare, Contrast,
Discriminate, Relate
Sort, Analyze, Query
Classify, Identify, List
Sort, Query
Assemble, Report
Report Customization
Advantages of Databases
Applicability to many different types of
problems involving:
 Data collection, analysis,
and manipulation.
 Comparison, synthesis,
and evaluation.
 Relationships between
data.
 Arranging, organizing,
and collecting data.
Advantages of Databases
 Fast, efficient data access and reporting.
 Built-in search and retrieval functions.
 Good for data integrated from many
sources.
 Flexible, user-friendly formats for storing
the contents of fields.
Advantages of Databases
 Reduce inconsistencies when users
carefully define, enter, and verify data.
 Cost-effective way to generate answers to
questions related to information
processing needs.
 Save time when data must be located,
updated, and retrieved.
Advantages of Databases
 Maintains data integrity when there is a
“few-to many relationship” i.e., only one
or two people actually define and update
the database, while many use the data
contained therein.
 Security is available through protected
copies and passwords in many database
packages.
 Built-in wizards, templates, and imported
data.
Disadvantages of Databases
 Duplication or redundancy.
 Difficulty evolving the database over time.
 Difficulty building the database for
complex problems and applications.
 Difficulty defining fields and establishing
guidelines for data entry.
Student Misconceptions
About Databases
 Queries and Filters are one in the same.
 The most important thing to remember
about constructing a database is entering
data appropriately.
 Databases are not used for calculation.
Correcting Misconceptions
about Databases
 Queries and filters are one in the same
Actually, these are different; queries are usually
more specific, involve more steps, and utilize
more data fields to select required criteria.
 The most important thing to remember
about constructing a database is
entering data appropriately.
This is good, but it is more important to plan the
database well by specifying needed data and
establishing firm guidelines for data entry.
Queries vs. Filters
 Good situations for a setting a query:

Using more than one table for data
selection.
 Performing calculations on selected record
values.
 Viewing only some of the fields in a record.
 Good situations for setting a filter:
Viewing only a subset of records.
Disadvantages of Filters
 Filters allow you to select
criteria one field-at-a-time,
and they are very
restrictive
(all criteria must be met
before a record is displayed).
Queries
 More powerful selection instrument,
because you can use related tables.
 You only display the fields you add
to the query.
Correcting Misconceptions
about Databases
 Databases are not used for
calculation.
Although complex formulas and
sophisticated computations are
better served by other tools, you
can create computed fields with
numeric data fields and generate
some statistical data (averages,
minimum and maximum values,
standard deviations, and grand
totals) for reports.
Correcting Misconceptions
about Databases
 Once data is entered, the
database should be used
to construct reports.
 Difference between
sorting and indexing.
 Specifying data types.
Correcting Misconceptions
about Databases
 Once data is entered, the database
should be used to construct reports.
Data should be verified and validated before
constructing reports.
 Difference between sorting and
indexing.
Sorting has to do with the physical
arrangement of data, while indexing deals
only with the organization of the common key
field.
Correcting Misconceptions
about Databases
Difference between sorting and indexing.
Sorting
Physical arrangement based on
a specified order. Example:
arranging names alphabetically
– As listed before Bs, etc…
Indexing
Records appear based on how
they are entered, but a unique
key field contains an
Identification number for each
record that identifies its
position. Example: Abraham,
Jane, might be listed after
Hinton, Bob, but the key field
uses an ID number that
appropriated sequences these
names alphabetically.
Correcting Misconceptions
about Databases
 Specifying data types
This is extremely important. If default data
types (integer, character, fixed, etc.) are
used, comparisons, calculations, and
results will be inaccurate. Always specify
the data’s type to avoid confusion and
ensure correctness.
References
Bitter, G., and Pierson, M. (2002). Using Technology
in the Classroom. 5th ed. Allyn and Bacon: Boston.
Morrison, G., and Lowther, D. (2002). Integrating
Computer Technology into the Classroom. 2nd ed.
Merrill Prentice Hall: New Jersey.
Summary
Electronic databases can save time and help
user’s prepare, manipulate, organize, and
disseminate data that answers questions and
solves information processing problems.
The database’s ability to compile, manipulate,
and store large quantities of information in
short time periods makes it a viable and
useful tool in both education and industry.