yawnston

Query Example

For each customer, return their name and surname, as well as the list of all products this customer bought, which have a maximum price of 150 EUR.

SELECT {
  ?customer cheapItems _:cheapItems ;
            name       ?name        ;
            surname    ?surname     .

yawnston

version: "2.4"
networks:
  mmcat:
    driver: bridge
    name: mmcat

volumes:
  mmcat-postgres:
  mmcat-postgres-data:
  mmcat-mongo-data:

yawnston

Figure 4

• Nemyslim si ze dava smysl opakovat FROM clause, t.j. mit vice FROM klauzuli. My ji pouzivame k tomu, abychom vybrali schema ze ktereho dotazovat.

Figure 5

• WHERE neni v MMQL optional, vzdy tam musi byt. Prijde mi ze obrazek naznacuje, ze by to tam byt nemuselo (pokud mu spravne rozumim).

Figure 6

• BIND momentalne nepodporujeme, teoreticky by to slo, ale otevreli bychom se tomu, ze se uvnitr toho objevi nejaka velka agregace napric vice databazemi, a bylo by podle me slozite definovat, jak se to ma prekladat. Kazdopadne na urovni jazyka tomu nic nebrani, je to spis implementacni slozitost.
• V obrazku chybi VALUES
• Nepodporujeme GRAPH, protoze to nedava v kontextu MMQL smysl

Figure 7

• Nepodporujeme NOT EXISTS ve verzi MMQL kterou jsem navrhoval v diplomce - dle me uvahy jde NOT EXISTS ekvivalentne vyjadrit pomoci podporovaneho MINUS v kombinaci s filtrovanim

yawnston

# Notation -> is used as a simplification in place of a single morphism, for example 1 or -1. This is for simplification since I don't know the exact schema.
#   Similarly ->> means a traversal like 1/2 or 1/-2 or similar, basically just a compound morphism traversal.

SELECT {
	?result -> ?address ;
		# Cypher-like aggregation - set of neighboring variables is the aggregation set (in this case streetName adn city)
		-> COUNT(?sameAddressOrder) AS ?orderCount .

	?address -> ?streetNumber ;
		-> ?city .