example QuickCSV

#This example is recommended for anyone dealing with CSV data and is built-in to the IDE as QuickCSV. 
#It imports a set of cloud-based CSV files about land and water animals into CQL, 
#demonstrates basic CQL operations, and then exports the data to a local CSV file. 
#We use SQL types (String, Integer, etc).


# Our land and water schemas share a common overlap schema about amphibians,
# which we express using an import statement.

schema AmphibianSchema = literal : sql {
	entities 
		Amphibian Animal
	foreign_keys 
		toAnimal : Amphibian -> Animal    
	attributes	
	     species : Animal -> String
}

schema LandSchema = literal : sql {
	imports
		AmphibianSchema
	entities
		LandAnimal	
	foreign_keys 
		isA : Amphibian  -> LandAnimal
		isA : LandAnimal -> Animal
	path_equations 
		Amphibian.isA.isA = Amphibian.toAnimal     
} 

schema WaterSchema = literal : sql {
	imports
		AmphibianSchema 
	entities
		WaterAnimal	
	foreign_keys 
		isA : Amphibian  -> WaterAnimal
		isA : WaterAnimal -> Animal
	path_equations 
		Amphibian.isA.isA = Amphibian.toAnimal     
} 

#Next, we import data from the internet.  CQL expects one file per entity, with one column
#per foreign key or attribute.  There are many options, such as providing a column to column
#name mapping during import, or to generate missing fields, etc; for details, see the built-in
#CSV example.   

instance LandInstance = import_csv "https://categoricaldata.net/demo/LandDB/" : LandSchema 

instance WaterInstance = import_csv "https://categoricaldata.net/demo/WaterDB/" : WaterSchema 

#command clear = exec_cmdline { "rm -rf exportedLand" }

command exportLand = export_csv_instance LandInstance "exportedLand/"

# It's recommended to use a trailing slashes to indicate a directory, 
# but the string is actually used as a prefix in a URL. 
instance backAgain = import_csv "exportedLand/" : LandSchema

instance LandInstance

instance WaterInstance

instance backAgain

command exportLand

Export to exportedLand/.