Quiz 4 Flashcards
(17 cards)
What does the GIS analysis process consist of?
- Capture
- Display
- Storage
- Analysis
- Management
- Retrieval
What are the three query operators?
- Project
- Restrict/Select
- Join
Project
π(some attribute) will call the instances of the selected attribute
e.g. πC where C can mean either East or West will pull a column of C: East, West
Restrict/Select
O(some attribute) < or > (some value) will call the rows and columns that fit the specified value
e.g. oB>45 where all B values over 45 will be selected along with their related attributes
Join
Merge more than one table and combine identical values(?) to reduce data redundancy
SQL
Standard Query Language
SQL Domains
Limits on values of an attribute
e.g. True & False – any real number
Any string – >50
Any integer – R^2
CREATE DOMAIN
name type[default][constraints]
where [default] and [constraints] are optional
Schemas
- Tell us attributes in a table
- Identify keys
- Provide additional constraints (pp for example)
Select command
SELECT item-list
FROM table-list
[WHERE condition] (condition on the FEATURES)
[GROUP BY attribute-list]
[HAVING condition] (condition on the GROUPS)
The select command CANNOT handle…
spatial queries
SQL’s abilities in ArcGIS Pro specifically are….
limited
LIMIT 0,10;
Limits inquiry result to 10 rows (Arc can’t read this format)
What kind of character is the % in ‘%School’?
A wildcard character; anything can be in place of the %, so it denotes anything in the database which ends with or contains “School”
FEATURE_NA > ‘W’
Highlights anything W or after (alphabetically)
Arc seems to only accept “SELECT” FROM [table] WHERE pclause];” and….
nothing more complex than that
HAVING N > 10
Selects by attributes again BUT on the output table from Summarize Attributes
