Introduction to Database Systems
Objectives:
•Introduction to Database Concepts
•Introduce Microsoft Access
•Tables, Queries, Forms,
Reports etc
•Creating a simple database
table
•Indexing
CS&E 1111 AcIntro
Data, Information, & Database

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
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Data : A collection of numbers and text :
273448926
Information : Meaning derived from data
SSN # 273-44-8926
Database: A collection of related data stored in a
specific format to simplify retrieval. The phone
book and dictionary are examples of databases.
John Smith’s SSN # 273-44-8926
DBMS – Database Management Systems are
programs that help in the storage and retrieval of
information from databases. (Access, Oracle)
CS&E 1111 AcIntro
DBMS

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
Vs.
Store and retrieve data
Provide support for data
“organizing” and
selecting
Can do simple
calculations
Efficient data handling
Customers of VISA with
balance > 1000
Spreadsheets





Store and analyze data
Provide support for
complex calculations
Can do simple data
organizing and
selecting
Inefficient data
handling
What was the net profit
of VISA
CS&E 1111 AcIntro
Access DBMS
Objects
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Access DBMS “objects”:


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Tables - a list of data organized into fields and
records
Queries - question structures to sort, filter and
select specific information
Forms - structures for screen views of data
Reports - structures for written output of data
Program Modules - program code to perform
specific actions
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A Database Management System
Data Tables
Relationships
Data Input:
Onto Tables
Onto Forms
From files
Reports
DBMS
Query
Results
Queries
Program Modules
Output
Files
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An Inventory Database System
Forms:
Order
Transactions
New Vendors &
New Customers
Shipments
Program Modules
Tables:
Current
Inventory
New
Products
Vendor
List
Orders
Order
Details
Customer
Accounts
Program Modules
Daily Ship
List
Reports & Queries
Customer
Invoices
Accounts
Payable
Inventory
Low Message
Output File:
CS&E 1111 AcIntro
“Objects”: Tables
Data is stored in objects called Tables
• Data on tables are listed in rows called records
•A record consists of one or more ordered
categories called fields
•Field types include Text. Number, Currency,
Date etc. Certain fields are required fields and
must be filled
• Field Properties – format, validation rule,
required, size, masks, defaults, ranges
A table is a listing of multiple records, all records in a
table have the same fields
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Primary Key

A field, or combination of fields, which
uniquely identifies a record in a database
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Table Datasheet View: Bank Customers
Customers: Table
acct#
456
543
544
999
1112
2456
3064
3575
4456
5323
ssn
123456789
139555002
157745969
123456789
178301771
201529842
227776183
257436001
290951508
328824082
Primary
Key
lname
Sommer
Suyama
Lebihan
Sommer
Berglund
Trujillo
Moos
Citeaux
Callahan
Moreno
fname
Martín
Michael
Laurence
Martín
Christina
Ana
Hanna
Frédérique
Laura
Antonio
Field
address
5400 E. Broad ST
4110 Old Redmond Rd.
342 S. Drexel
5400 E. Broad ST
707 Oxford Rd.
7 Houndstooth Rd.
29 King's Way
3400 - 8th Avenue Suite 210
Coventry House Miner Rd.
49 Gilbert St.
city
Reynoldsburg
Worthington
Bexley
Reynoldsburg
Columbus
Marysville
Groveport
Columbus
Dublin
Cleveland
state
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
zipcode
43213
43201
43209
43213
43222
42001
43287
43210
43255
40032
Record
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A Second Table - “Transactions” keeps
track of all deposits and withdrawals
• What’s the Primary key on this table?
Account#
456
544
2456
3064
4456
5323
5566
456
544
1112
4456
date
4/1/2012
4/1/2012
4/2/2012
4/2/2012
4/3/2012
4/3/2012
4/4/2012
4/9/2012
4/9/2012
4/11/2012
4/12/2012
transaction$
$1,231.39
$3,366.82
$2,301.68
$5,087.66
$12,838.42
$167.80
$641.92
($1,186.26)
($3,243.43)
$159.66
($12,367.91)
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Walkthrough: Setting up a Table using Design View
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Divide Tables into Inseparable Fields
Address as 1 field –


17 Main St. New York, New York 10002
Address as 4 fields

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Street Address - 17 Main St.
City - New York
State - New York
Zip code – 10002
If you wanted to filter the table to get a list of only
New York City residents how would this work with
these two different Table structures
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Defining Properties for each Field in a Table
For a person’s social security number use:
 What field type?

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Text, Number - Short Integer, Number- Long
Integer etc.
Should it be optional or required?
Does the value need to be within certain
limits or from a predefined list?
Is there a default value?
Would an input mask be appropriate
CS&E 1111 AcIntro
Memory and Field Size
Why adjust the field size for Social security number?

Text:


Memo:

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Up to 255 characters
Up to 65,535 characters
Numbers:



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Integer - 2 bytes - 16 bits
Long Integer - 4 bytes - 32 bits (*)
Byte (character) - 1 byte
Single - 4 bytes - -precision 7
Double - 8 bytes - -precision 15
CS&E 1111 AcIntro
How should you decide what information
goes on which table?

If a fact appears in more than one record of a table,
then this fact should probably be defined in another
table.

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Each fact change should change in only one place

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Example: Address
Calculations shouldn’t be part of the database


Example: Account number
Example: Current Balance
Select a Primary Key where applicable so you can
relate your tables

Example: Account number
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Tools: Sorting and Filtering


Sorting - allows the user to temporarily order the
records by a specific field
 Ascending or Descending order
 Single or multiple sort fields
Filtering - allows the user to view only specific
records that meet the criteria
 Filter by form or filter by selection
 Specify a single criteria or use Boolean and/or
for multiple criteria in multiple fields
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Storing and Retrieving Records from Tables
How are DBMS systems designed to
efficiently handle data?

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Data is stored on magnetic or optical disk in a linear
fashion
To retrieve a specific record one would have to search
them one at a time until the desired record is found.
To make data retrieval more efficient one can “index” a
table based on a specific field.
Search routines could then be used on that field to more
efficiently find the record
Example: Alphabetically sorting a dictionary and then
analyzing the first letter of the criteria in the sorted list.
CS&E 1111 AcIntro
Linear Search on Un-indexed Field
Find the name of student for ss#606147775
ssn
606147775
178301771
988544806
290951508
257436001
874775203
419975418
371616449
536370683
774094122
157745969
474621100
227776183
328824082
684995818
123456789
139555002
201529842
lname
Anders
Berglund
Buchanan
Callahan
Citeaux
Davolio
Dodsworth
Fuller
Hardy
King
Lebihan
Leverling
Moos
Moreno
Peacock
Sommer
Suyama
Trujillo
fname
Maria
Christina
Steven
Laura
Frédérique
Nancy
Anne
Andrew
Thomas
Robert
Laurence
Janet
Hanna
Antonio
Margaret
Martín
Michael
Ana
•Go to the first record to
see if 178301771 matches
606147775. If no match
then check the next record
until a match is found.
•Here it must check 11
items before you find the
correct one. On average it
will have to check
#entries/2
CS&E 1111 AcIntro
A Binary Search on an Indexed Field
Find name of student for ss#606147775
This table is sorted by SSN
ssn
123456789
139555002
157745969
178301771
201529842
227776183
257436001
290951508
328824082
371616449
419975418
474621100
536370683
606147775
684995818
774094122
874775203
988544806
lname
Sommer
Suyama
Lebihan
Berglund
Trujillo
Moos
Citeaux
Callahan
Moreno
Fuller
Dodsworth
Leverling
Hardy
Anders
Peacock
King
Davolio
Buchanan
fname
Martín
Michael
Laurence
Christina
Ana
Hanna
Frédérique
Laura
Antonio
Andrew
Anne
Janet
Thomas
Maria
Margaret
Robert
Nancy
Steven
1. First go to the middle record of the
table and compare values to see if
606147775>328824082.
2. If it is greater, continue checking
only from this midpoint to the end.
Otherwise continue checking only
from the beginning to the
midpoint
3. Then go to the midpoint of this
subsection. The process continues
until a match is found
Indexing can aid in querying efficiency using algorithms such as binary
search (1/2,1/2 again) vs. a linear search (1 at time from top to bottom).
A binary search cuts the processing time significantly for large databases
CS&E 1111 AcIntro
Indexing vs. Sorting
Sorting your table & saving permanently changes
the record order.. Use an index instead.
ssn#606147775 is
associated with
record 14
ssn
123456789
139555002
157745969
178301771
201529842
227776183
257436001
290951508
328824082
371616449
419975418
474621100
536370683
606147775
684995818
774094122
874775203
988544806
lname
Sommer
Suyama
Lebihan
Berglund
Trujillo
Moos
Citeaux
Callahan
Moreno
Fuller
Dodsworth
Leverling
Hardy
Anders
Peacock
King
Davolio
Buchanan
fname
Martín
Michael
Laurence
Christina
Ana
Hanna
Frédérique
Laura
Antonio
Andrew
Anne
Janet
Thomas
Maria
Margaret
Robert
Nancy
Steven
CS&E 1111 AcIntro
From Tables to a Relational Database
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We have carefully looked at tables in our database
how to set them up, define fields etc. The real
advantages of a DBMS however are in their ability
to relate information.
Thus far we have customer names on one list and
transactions on a separate list. How do we match
a customer’s name to specific transaction?
We need a way to relate these two tables to extract
useful information. We can relate these two tables
by matching the account numbers.
CS&E 1111 AcIntro
One to Many Relationship
Customers: Table
acct#
456
543
544
999
1112
2456
ssn
123456789
139555002
157745969
123456789
178301771
201529842
lname
Sommer
Suyama
Lebihan
Sommer
Berglund
Trujillo
fname
Martín
Michael
Laurence
Martín
Christina
Ana
Acct#/Account No. is
the Foreign Key
address
5400 E. Broad ST
4110 Old Redmond Rd.
342 S. Drexel
5400 E. Broad ST
707 Oxford Rd.
7 Houndstooth Rd.
Account#
456
544
2456
3064
4456
5323
5566
456
544
1112
4456
city
Reynoldsburg
Worthington
Bexley
Reynoldsburg
Columbus
Marysville
date
4/1/1999
4/1/1999
4/2/1999
4/2/1999
4/3/1999
4/3/1999
4/4/1999
4/9/1999
4/9/1999
4/11/1999
4/12/1999
state
OH
OH
OH
OH
OH
OH
zipcode
43213
43201
43209
43213
43222
42001
transaction$
$1,231.39
$3,366.82
$2,301.68
$5,087.66
$12,838.42
$167.80
$641.92
($1,186.26)
($3,243.43)
$159.66
($12,367.91)
CS&E 1111 AcIntro
A Foreign Key is a field that defines the
relationship between 2 tables:
A valid foreign key must have all of the properties
listed below:
1. Must be a primary key (unique) in at least one of
the tables
2. The field names on each table do not have to
match as long as the information is the same.
Fields with the same name does not necessarily
mean they are the foreign key.
3. The related fields must be the same data type
(number, text etc)
CS&E 1111 AcIntro
Walkthrough: Establishing relationships
Primary Key on Accounts table: acct#
Foreign Key: acct#/Account#
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Once Relationships are established you
can gather information from one or more
tables to answer questions like:



Create a list of account numbers and owner
names and total transactions
What are the total deposits made by accounts
starting with 5?
What is the total balance of all accounts held by
Jane Doe ?
These requests are known as Queries
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“Objects”: Queries
To extract information from the Database use a
Query which is a “question” or “request”
The query is not the data that results but a set of
instructions specifying how specific records or
combinations of records should be extracted - it lets
the user:
prepare lists, sort, filter
choose records to met specific criteria
do calculations on the data
Summarize data by a specific grouping
match up the data to related information
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CS&E 1111 AcIntro
Walkthrough: A Simple Query
Create a query to list the first name, last name and transaction
amount for each transaction
We will spend the next 1-2 weeks learning, in greater detail,
how to use the query tool.
CS&E 1111 AcIntro
“Objects”: Forms
A form is not data
that results but a set
of instructions
specifying a screen
view format of the
data. These forms
are designed to
simplify data
display, inputting
and editing.
Walkthrough: Setting up a form
CS&E 1111 AcIntro
“Objects”: Reports
A report is not the data that results but a set of
instructions specifying the format of written output.
Reports allow users to vary :




The type of text formatting
Report & Page headers, footers, titles
Which data fields (from tables, queries
and/or calculations) to be used
Sorts, Filters, Groupings of fields
Walkthrough: Setting up an AutoReport
CS&E 1111 AcIntro
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“Objects”: Macros &Modules
Programmed instructions

updating tables/queries from inputs




customer address
account balance
retrieving data from other sources
performing tasks if a certain criterion is met


monthly bank statement
balance > 20000
 send letter offering estate planning service
This course will not cover the Macros & Modules - we can
refer you to more Advanced books on Access & Visual Basic
CS&E 1111 AcIntro
A Review of Database Theory

Information is stored in objects known as tables
consisting of records or related information
categorized into fields.



A field that uniquely identifies a table is known as a
primary key field
Tables can be related to each other using valid
foreign key fields.
Queries, Reports, Forms are objects which can
be created using the data on tables to dynamically
extract/display information in a specified format.
CS&E 1111 AcIntro