1. Introduction to Database Systems
Objectives:
Introduction to Database Concepts
Introduce Microsoft Access
Tables, Queries, Forms, Reports etc
Creating a simple database table
Indexing

2. Data, Information, & Database
Data : A collection of numbers and text :
Information : Meaning derived from data
SSN #
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 #
DBMS – Database Management Systems are programs that help in the storage and retrieval of information from databases. (Access, Oracle)

3. DBMS Vs. Spreadsheets Store and retrieve data
Provide support for data “organizing” and selecting
Can do simple calculations
Efficient data handling
Customers of VISA with balance > 1000
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

4. Access DBMS
Objects

5. Access DBMS “objects”:
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

6. A Database Management System
Data Tables
Relationships
Data Input:
Onto Tables
Onto Forms
From files
Reports
Query
Results
DBMS
Queries
Output
Files
Program Modules

7. An Inventory Database System
Forms:
Order
Transactions
New Vendors &
New Customers
New
Products
Shipments
Program Modules
Tables:
Current
Inventory
Customer
Accounts
Vendor
List
Orders
Order
Details
Program Modules
Customer
Invoices
Daily Ship
List
Accounts
Payable
Inventory
Low Message
Reports & Queries
Output File:

8. “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

9. Primary Key
A field, or combination of fields, which uniquely identifies a record in a database

10. Table Datasheet View: Bank Customers
Record
Field
Primary
Key

11. A Second Table - “Transactions” keeps track of all deposits and withdrawals
What’s the Primary key on this table?

12. Walkthrough: Setting up a Table using Design View

13. Divide Tables into Inseparable Fields
Address as 1 field –
17 Main St. New York, New York 10002
Address as 4 fields
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

14. Defining Properties for each Field in a Table
For a person’s social security number use:
What field type?
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

15. Memory and Field Size
Why adjust the field size for Social security number?
Text:
Up to 255 characters
Memo:
Up to 65,535 characters
Numbers:
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

16. 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.
Example: Account number
Each fact change should change in only one place
Example: Address
Calculations shouldn’t be part of the database
Example: Current Balance
Select a Primary Key where applicable so you can relate your tables

17. 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

18. Storing and Retrieving Records from Tables
How are DBMS systems designed to efficiently handle data?
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.

19. Linear Search on Un-indexed Field
Find the name of student for ss#
Go to the first record to see if matches 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

20. A Binary Search on an Indexed Field
Find name of student for ss#
This table is sorted by SSN
First go to the middle record of the table and compare values to see if >
If it is greater, continue checking only from this midpoint to the end. Otherwise continue checking only from the beginning to the midpoint
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

21. Indexing vs. Sorting
Sorting your table & saving permanently changes the record order.. Use an index instead.
ssn# is associated with record 14

22. From Tables to a Relational Database
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.

23. One to Many Relationship
Acct#/Account No. is the Foreign Key

24. 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:
Must be a primary key (unique) in at least one of the tables
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.
The related fields must be the same data type (number, text etc)

25. Walkthrough: Establishing relationships
Primary Key on Accounts table: acct#
Foreign Key: acct#/Account#

26. 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

27. “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

28. Walkthrough: A Simple Query
Create a query to list the first name, last name and transaction amount for each transaction
Design:
Dynaset Result:
We will spend the next 1-2 weeks learning, in greater detail, how to use the query tool.

29. Walkthrough: Setting up a form
“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

30. Walkthrough: Setting up an AutoReport
“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

31. Sample Report: Transactions by Customer

32. “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

33. 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.