1. Application Software: Databases
CHAPTERS 15-16
Application Software: Databases

2. Databases A database is a collection of data
Database software helps you find, organize, update, and report information stored in a database

3. Database Concepts
Database Management System Software is used to create, maintain, and access information in an electronic database.
Common Database Management Systems
Microsoft Access
Borland dBase
mySQL
Oracle

4. Data Organization “Hierarchy”
Databases: a collection of files with the connections between them
Files : Information dealing with different types of data are stored in different files
(i.e. addresses, transcripts, and schedules)
Records : Each instance in a file is called a record (i.e. all information about one student)
Fields : Each part of a record is called a field
(i.e. Zip Code for a student)

6. Database Terminology Field Record Table Database A database is made up
of one or more tables
Field
Record
Table
Database
Individual fields
A database consists of one or more tables. Each table consists of records which contain information about a single entity. An example of one complete record would be the name, author, isbn#, published date and publisher of textbooks. Each set of information regarding one book is considered to be one record. The name, author isbn#, published data and publisher in the above example are the individual fields that make up one record.
Individual tables in a database
Records 6 6

7. Tables in a Database
Each DB file has a table structure for its records.
The table structure is created first and given a table name as well as a set of fields.

8. Table Design Considerations
Just as you first create a blueprint to build a house, you should first sketch or outline the design of a database table
Careful pre-planning
will save you much time
in the future
Just as you first create a blueprint to build a house, you should first sketch or outline your table design. (Add: Careful pre-planning saves you much time in the future. There are many factors that affect both the design and structure of a database. 8

9. Tables in a Database Each Field in the table has…
name
data type
field width
After the table structure is complete, data can be entered into the table’s fields.
default values
required?
primary key?

10. Data Types for the Fields
Text
alphanumeric, alpha, string – holds any character
Numeric
byte, short, long, integer
floating point (decimal) , currencies
Date
Memo
Logical (binary or boolean or yes/no)
Hyperlink
Object

12. Table Design Considerations – Field Size Property
Set field size in the Field Properties
grid of Table Design View
Set the field size property of individual fields in Table Design View. Once the field size is set, data entry in that field is limited to the length specified. In order to prepare for the future, always anticipate the current field size may one day need to be larger.
Set the field size in Table Design View
Always anticipate the current field size, may one day need to be larger 12

13. Data Validation
Make sure the data in the computer matches the real-world information it represents
Data Type Enforcement
Default Values
Ranges
Required Fields
Unique Keys
Non-Null Keys

14. Data Validation
Make a field numeric types ONLY when you plan to do arithmetic with the field and it makes sense to do it!
Social security numbers, for example, should be TEXT not Long integers – you do not want someone to total them by accident, it would be meaningless

15. Table Design Consideration – Sarbanes Oxley Act (SOX)
Protects the general public and companies shareholders against fraudulent practices and accounting errors.
Requires that all business records be saved for a period of five years and be made available to the SEC upon request
This regulation protects the general public and companies shareholders against fraudulent practices and accounting errors. To summarize the act, it requires that all business records be saved for a period of five years and be made available to the SEC upon request.
SOX RECORDS
Do Not
Discard 15

16. Table Design Considerations - PNPI
Short for Personal, Non-Public, Information
PNPI laws govern the safeguarding of data such as:
social security numbers
credit card numbers
Educational records (FERPA)
bank account numbers
medical records (HPAA)
Short for personal, non-public, information, PNPI laws govern the safeguarding of data such as social security numbers, credit card numbers, bank account numbers and medical records. 16

17. Table Design Considerations – Store Data in its Smallest part
Like this
Not like this
For greater flexibility, store data in its smallest part. It is much more difficult to search for data when more than one piece of information is in one field. Examples include: instead of one field for a persons address, break the address into three fields – street address, city, state and zip. Instead of one field for a persons name, break the name into two or three fields – first, last and possibly middle initial.
For greater flexibility, store data in its smallest part
Instead of one field for an address, use many
Instead of one field for a name, two or three 17

18. Table Design Consideration - Plan for Date Arithmetic
Fields declared as a data type of Date/Time
Using a data type of date/time for all date fields allows the use of date arithmetic. An example of date arithmetic usage would be subtracting the shipping date from the order date of an item. The resulting number is the delay between the item being ordered and the item being shipped.
Using a data type of date/time for all date fields allows the use of date arithmetic 18

19. Work with Table Views
Design View
Datasheet View
When working with tables, two different table views exist. Datasheet View is used to add, modify, view, and delete records. You may also choose to enter field names in this view when you are first creating your table. The other view, Design View, does not allow record entry. It is used for entering field names and specifying properties of the fields, such as the size of the field. You may also edit existing fields, including those that were first created in Datasheet View.
Datasheet (Table) View – used to add, modify, delete and view records
Design View – used to create and modify the fields in a table 19 19

20. Work with Properties
Field Size property
Caption property
Field Properties can be used to specify characteristics for individual fields. Field Properties can be found in the lower pane of the Table Design View.
Field Properties can be used to specify characteristics for individual fields
Located in the lower pane of Table Design View 20

21. Objects Tables Queries Reports Forms Macros Modules Objects
The elements of a database are referred to as objects. Access utilizes six different types of objects: tables, queries, reports, forms, modules, and macros. Of these six objects types, the only mandatory object is one table. All other objects may or may not be included in the database per the database users needs. Objects are located in the Navigation pane of the Access window.
Objects 21 21

22. Reports Reports are created when a more formal printout is desired.
Use a wizard to create a report
Executes one or more queries and presents the results in a more organized fashion
Can sort the data, can do simple arithmetic (totals)

23. Queries
Queries are questions used to retrieve information from a database.
Contain criteria to specify the records and fields to be included in the query results.
Can contain wild cards or logical operators to make more complex queries
* and ?
<, >, <=, >=, <>, =, AND, OR, etc…
Named and saved so they can be run again at a later time.

24. Query Languages
A query language such as SQL (Structured Query Language) provides a set of commands for locating and manipulating data
LIST ALL FOR STATE = “KY”
Not user friendly
Query By Example is another query language
Fill out a form that describes your query
More friendly

25. Queries Queries allow us to ask questions about data
Dataset resulting from querying table for only employees who are Sales Representatives
Employees table
Queries allow us to ask specific questions about the data and receive a record set back that answers our questions. This returned record set is called a dataset. Simply running a query does not change the actual table data. However, you may alter the data in a dataset and the changes will be reflected in the underlying table.
Queries allow us to ask questions about data
This record set that answers our question is called a dataset 25

26. Using Query Design View
Tables pane
Design pane
Query Design view has two panes – the table pane and the design pane. Striking the F6 key will toggle you between panes.
Query Design grid has two panes – the table pane and the design pane
Striking the F6 key will toggle you between sections 26

27. Specifying Criteria in a Select Query
Fields in design grid allow us to specify criteria for the dataset
Field row – displays the field name
Sort row – enables you to sort the dataset
Show row – controls whether or not you see a field in the dataset
Criteria row – determines the records that will be selected for display
Parts of the Design Grid include:
Field Row – displays the field name
Sort row – enables you to sort the dataset
Show Row – controls whether or not you see a field in the dataset
Criteria row – determines the records that will be selected for display 27

28. Specifying Criteria – Currency and Operands
Currency amount entered without dollar sign
Greater than (>) operand
Specify criteria with currency
Without the dollar sign
With or without the decimal point
Use operands such as:
Less than and greater than
Equal to or not equal to
Specify criteria with currency without the dollar sign and with or without the decimal point. Use operands such as less than, greater than, equal to or not equal to, in order to compare your criteria against data in the specified field. 28

29. Specifying Criteria – Wildcards
Query with question mark and asterisk wildcard and resulting dataset to specify criteria for the dataset
Query with asterisk wildcard and resulting dataset
The asterisk wildcard searches for a pattern that includes any number of characters in the position of the asterisk.
The question mark searches for a pattern that includes a single character in the position of the question mark.
Asterisk - searches for a pattern that includes any number of characters in the position of the asterisk
Question mark - searches for a pattern that includes a single character in the position of the question mark 29

30. Specifying Criteria – And and Or
Or Criterion and resulting dataset
And criterion and resulting dataset
Use the OR criterion to find records that can match one or more conditions specified. Use the AND criterion to find records that must match all criteria specified.
OR finds records that can match one or more conditions
AND finds records that must match all criteria specified 30

31. Run a Query
Run command
Running, or executing, a query is done by clicking the Run command located by clicking the Design tab and accessing the Results group.
Running, or executing, a query is done by clicking the Run command 31

32. Add a Total Row in a Query
The total row can be added to the design grid by clicking the Totals Icon
Totals Icon
The total row can be added to the design grid by clicking the Totals Icon.
Total row added to the query

33. Calculated Queries Will find averages, max, min, sum, std
Work with ONE field – NOT more!
Add Totals row to query
Open “Group By” menu
Choose appropriate function
Run query

34. Sorting Records Can sort records in a database by field values
Single Field Sort
Sort all students in the DB by home state
Multi-Field Sort (Field A within Field B)
Sort all students in the DB by home state then by alphabetical order of last name (Name within State) State is primary sort field, Name is secondary sort field
Access sorts multiple fields left to right

35. Sorting Table Data
Last Name field sorted descending
Last Name field sorted ascending
The Sort feature in Access, just like the other Office applications, allows you to lists records in ascending or descending order according to one or more fields.
Lists records in ascending or descending order according to one or more fields 35 35

36. Concurrent Processing
Large databases allow more than one person to access a file at one time
Have to be careful to control access - can lose data that way - who writes LAST?
MS Access uses a .ldb file to control this
.ldb file created when a mdb file is opened, says that it is "locked" so no one else can use it
.ldb file goes away when mdb file is closed
DO NOT submit it INSTEAD of your mdb!

37. Compact and Repair
Compact and Repair is located under the Manage menu
Fixes problems due to inefficient file storage and growth of a database
Should be performed everyday
Often decreases the file size by 50% or more
Compact and Repair helps fix problems due to inefficient file storage and growth of a database. You should use the compact and repair command every time you work with a database. This process often decreases the file size by 50% or more. 37 37

38. Access or Excel? Use Excel when: Use Access when:
Your data is of a manageable data size
There is no need for relationships between data
You are primarily creating calculations and statistics
You are working with large amounts of data
You need to create relationships between your data
Use Excel when:
1. Your data is of a manageable data size
2. There is no need for relationships between data
3. You are primarily creating calculations and statistics
Use Access when:
1. You are working with large amounts of data
2. You need to create relationships between your data
3. You rely on external databases to analyze data 38 38

39. Understand Large Database Differences
Most large companies separate their database into front and back ends
Front end – contains the objects needed to interact with data, but not the tables where the record values reside
Back end – contains the tables where the data resides
To ensure data integrity, to maintain security and to avoid mishaps, most large companies separate their database into front and back ends.
Front end – contains the objects needed to interact with data, but not the tables where the record values reside.
Back end – contains the tables where the data resides 39

40. Data Mining – a question for society
the process of extracting hidden patterns from data (from Wikipedia)
Businesses and governments do it all the time (finding prospects, detecting terrorism)
For Knowledge Discovery and Prediction
Privacy concerns – identifying specific individuals