Spreadsheet vs Database

• When do we use them?

Spreadsheet review

• Why do we use a spreadsheet?

Spreadsheet review

• Enter data

• Do calculations on data

• Examples: expenses, profit/loss

Expenses

Gradesheet

Database

• Store information long-term

• Search information

An example…

• What sort of information does Ren Da Fu Zhong need to keep?

• Think of at least 10 pieces of information!

RDFZ stores information on…

• Students:– Name, address, ID number, parents, grades,

classes, teachers, payment info, absences, extra activities

• Teachers:– Name, address, ID number, classes taught,

students taught, grades given, bank information, payment information

RDFZ stores information on…

• Other employees:– Name, job, hours worked/week, pay scale,

bank information, duties/responsibilities

• Inventories:– How many classrooms, how many desks,

chairs, overhead projectors, scanners, computers…

RDFZ stores information on…

• Lots of stuff!

• Can all of this fit on one spreadsheet?– No!– This is when we use a database.

Uses of a database

• Store data

• Backup data

• Add/Modify data

• Query data (ask questions)

• Generate reports (print data in an easy-to-read format)

Examples of databases

• Can you think of any?

Your music

Your games

Your web pages

Your life

Warning!

• Databases are very different from word processors, spreadsheets, or presentation software.

• You CANNOT just start typing.

• A database must be DESIGNED before you start adding data.

• Why?

Why?

• Avoid duplication (putting in the same data many times)

• Logical organization of data

The parts of a database

• Do you remember:– Columns?– Rows?– Cells?

• These have different names in a database…

Table: one page

Column = Field

• We have 3 fields: ID, title, and date

• Notice – every field has the same data type!

• This is required!

Data Type review

• Remember these from Excel?

Row = Record

• Here we have 4 records• Each record has all the information from one

entry.

Another example

• Here we have 3 records• A record has all the info on one entry

Cell: Data Value

• How many data values are in this table?

Primary Key

• Here, the “Video Collection” field is the primary key

• EVERY table MUST have a primary key – a unique value

Primary Key Examples

Designing a Database

• Before we enter data, we must design the table

• Things to think about:– What fields do we need?– What data type does each field need?– Which field can become the primary key?

Example: RDFZ

• What information will RDFZ store about students?

• What data type should each be?

• Which field will make a good primary key?

Example: Taobao business

• We are running a business on TaoBao. We are selling clothing on the internet. We want to make a database of all the orders that we receive.

• What information must we store?

• What data type should each field be?

• What should be the primary key?

Example: a new home

• We are real estate agents, and need to build a database of all apartments in the area.

• What information must we store?

• What data type should each field be?

• What should be the primary key?