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 A collection of data organized in a way that allows:  Easy access  Easy retrieval of specific data  Easy use of the data.

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Presentation on theme: " A collection of data organized in a way that allows:  Easy access  Easy retrieval of specific data  Easy use of the data."— Presentation transcript:

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2  A collection of data organized in a way that allows:  Easy access  Easy retrieval of specific data  Easy use of the data

3  First, consider what you want the database to do for you.  Database design is arranging information into tables and fields.

4  What tables will be needed?  Consider the types of information that will be used: employees, inservice classes, attendance at inservices.  Will there be primary keys?  Are there any extra fields needed?  Are there relationships among the fields?  What are the types of data in each field?

5  Is there duplicated data between tables?  It can cause problems when updating  It wastes space  It could make data inconsistent  Where will the database be stored?

6  Minimizes duplicated data  Info is more accurate and consistent  Easier to enter data using forms  Easier to view and sort info in many different ways  Easier to add passwords and use security features  Easier to share and edit information at the same time with other database users

7  Names can be 64 characters long  Names can include letters, numbers, spaces and most types of punctuation  Names cannot contain periods, exclamation points, access graves or brackets  Field names cannot be duplicated

8  Our database will include:  Information about employees  Information about Inservices Classes offered  Information about attendance at these classes

9  Employee Social Security Number for the employee table would be reasonable.  Due to privacy and identify theft, we will assign each employee an employee ID number.

10  Employee Table  See “Employees” Excel spreadsheet  Need fields for each of the columns contained in the spreadsheet  Inservice Classes Table  Each class will be assigned a Class No.  See Inservices Classes Table to identify fields needed  Inservice Attendance Table  ID No. for each “transaction”  Employee ID No.  Inservice Class No.

11  To keep from duplicating information, we’ll create relationships between the three tables.  One employee can attend many inservice classes.  One inservice class can be attended by many different employees.

12  Look at the Employees Excel spreadsheet.  Determine the data type for each of the columns.  Three most common data types:  Text – can contain up to 255 characters (wow!)  Number – can be only positive or negative numbers. To use data in mathematical operations, it must be identified as a number.  Currency – only monetary data. Will contain $ signs, commas, decimals points, and 2 decimal places. Can be used in mathematical calculations.

13  Review tables and fields.  Is there information that is duplicated between tables?  If so, it will make it more difficult to correct errors, take up more disk space, etc.


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