Data Organization Chapter 9

1
Data Organization (Chapter 9)

• Field (e.g., employee number)
• Record (e.g., employee record)
• File (e.g., group of records)

2
Folder

• Branches of a tree
• Subfolder
• How do you organize your folders in the computer?
  Is it efficient when you look for certain files?
• How do you backup your files? Backup the entire
  hard-drive?

3
Organize Data Files

• Function
• Frequency of use
• Users
• Projects

4
Key Field

• A value that uniquely identifies each record
  (e.g., student ID)
• With the key field, one can sort, filter, and
  locate records

5
History of Database

• Hierarchical Database Structure
• 1964, GE developed Integrated Data Store
• Network Database Structure
• 1971, CODASYL
• Relational Database Structure
• 1977, Codd described relational algebra between
  fields

6
Relational Database

• Common column the implicit linkage
• the other two types of database may need Physical
  Relationships
• Used book example
• Microsoft Access

7
Structured Query Language (SQL)

• A language to manipulate data in the database
• Reference
• Visual Basic ????????? with ACCESS SQL Server,
  ?? (1999)

8
Enter Data

• Input into a spreadsheet
• Input into a custom-made form

9
Retrieve Data

• Person
• Terminal or PC
• Other applications
• Client-Server structure
• VB linked with SQL or Oracle server

10
Data Description Language

• How you define each field
• Personal ID must have 10 digits with the first to
  be an alphabet
• Zip code is always 3 digits
• Salary is always non-negative
• Name wont contain any numerical digits

11
On-line Analytical Processing(OLAP)

• E-commerce
• Analyze your existing customers
• who may be your potential customers?

12
Knowledge Discovery in Database

• Data Warehouse
• Data Mart
• Smaller database within a warehouse
• Data Mining
• Finding relationships in data that are unknown to
  the user
• Verification-driven, Discovery-driven, Combined