1. NSF DUE-1205110; 0903270 Chérie Aukland

2. NSF DUE-1205110; 0903270 GeoTEd Partners

3. NSF DUE-1205110; 0903270 Module Outline Introduction Problem: mapping student data Review Tables Attribute Tables Standalone Table Joins Quick overview of cardinality Relates

4. NSF DUE-1205110; 0903270 Introduction Consider the following examples You are collecting data in the field using a GPS and paper and pencil to be entered into a spreadsheet later. How do you connect that pencil and paper data with your GPS data? You want to map the all of the HUD homes in Virginia, but once you select the homes you want, you get a spreadsheet download. (http://www.hudhomestore.com/Home/Index.aspx)http://www.hudhomestore.com/Home/Index.aspx What’s the problem?

5. NSF DUE-1205110; 0903270 Mapping Student Data We get an excel spreadsheet of student data to map for our college. We want to know the number of students per zip code.number of students per zip code Here’s our data, what else do we need?

6. NSF DUE-1205110; 0903270 Types of tables Recall: Attribute table Stores attributes of map features Associated with a spatial data layer Has special fields for spatial information Standalone table Stores any tabular data Excel tables, for example Not associated with spatial data The problem

7. NSF DUE-1205110; 0903270 4-7

8. NSF DUE-1205110; 0903270 4-8 Joining tables Joined table Destination tableSource table Common field Maribeth Price, © 2012

9. NSF DUE-1205110; 0903270 4-9 Join facts temporary Joins are temporary relationships between tables used by a relational DBMS Tables must share a common field (key) Treats the two tables as a single table Original stored data is not affected Can be removed when no longer needed

10. NSF DUE-1205110; 0903270 4-10 Rule of Joining destinationone and only one source Each record in the destination table must match one and only one record in the source table. One to one Destination table Source table Many to one Maribeth Price, © 2012

11. NSF DUE-1205110; 0903270 4-11 One to many Destination table Source table ? Violates the Rule of Joining, record to join to destination is ambiguous Must use a relate instead: Must use a relate instead: Similar to a join except that tables remain separate items selected in one table may be highlighted in the related table. Maribeth Price, © 2012

12. NSF DUE-1205110; 0903270 4-12 Types of Cardinality One-to-one States to Governors Husbands to wives One-to-many States to cities Districts to schools Many to one –Cities to states –Schools to districts Many-to-many –Students to classes –Stores to customers Maribeth Price, © 2012

13. NSF DUE-1205110; 0903270 Questions? Let’s do some hands on!