Working with Tables
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Transcript of Working with Tables
Working with Tables
Where the serious GIS work takes place.
One Feature – One Record
Field
or
Column
Record
or
Row
One Feature – One Record
Field Requirements
• Use unique column names
• Define the data type to be stored
• Appropriate width for attribute value.
Data Types will be discussed in the next lecture.
Joining and Relating Tables
A Common Field
One to One Relationship
Join the tables.
Many to One
Join the tables.
One to Many Relationship
Relate the tables.
Many to Many
Relate the tables.
Joining Tables
Joining to another table based on atributes.
This is the table you are joining
These are the common fields
Join Results
Original Coffee Shop Attribute Table (points)
Original Owners.dbf
Joined Tables
• The originals remain separated
• They can be unjoined
• You can use joined data to symbolize and classify.
• You can create statistics, charts and reports.
What happens if you join when you should relate for a One to Many?
Shape Area Name ID
point 32456 Smith 71
point 23412 Jones 64
point 16534 Green 22
ID Tax_Val Income
71 1400 42000
71 723 5701
64 3218 89055
64 127 879
22 465 2271
71 4213 120000
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Join will combine for the first record and then ignore the rest.
Relate will connect all the records.
What happens if you join in a Many to One
Shape Area Name Route
point 17864 Allan 14
Point 22341 Rios 14
Point 12221 Lee 9
point 32456 Smith 9
point 23412 Jones 27
point 16534 Green 27
Route Day Comp
14 M UPS
9 T FEDX
27 F AIRB
The records are duplicated in the Joined file
Multiple Joins and Relates(Daisy Chains)
Route
Route
Related Tables
Summarize Data
Create a Graph from Summarized, Selected Data
Chart of joined, summarized, selected data.