21: Querying graph relations

Querying a relation is usually done using the same arrow syntax used in the RELATE statement to create it.

Here is a query on a single person record which returns its name as well as the path ->works_at->place . The graph query checks to see if the person is linked to the works_at table (the in field, because the arrow at ->works_at is going in to works_at ) and if there is a place at the other end (the out field, because the arrow at works_at->place goes out from works_at and looks for a place record at that point).

SELECT 
    name, 
    ->works_at->place
FROM person LIMIT 1;

Response
[
	{
		"->works_at": {
			"->place": [
				place:surreal_library
			]
		},
		name: 'Lydia Wyndham'
	}
]

Since the place point in the query will look for place records, the .{} destructuring operator can be used to access the fields, such as name and address . We will also give it the alias workplace for readability, and remove the LIMIT to show all the person records.

SELECT 
    name, 
    ->works_at->place.{ 
		name, 
		address
	} AS workplace
FROM person;

Response
[
	{
		name: 'Sara Bellum',
		workplace: [
			{
				address: '2025 Statement Street, Riverdale',
				name: 'Surreal Library'
			}
		]
	},
	{
		name: 'Lydia Wyndham',
		workplace: [
			{
				address: '2025 Statement Street, Riverdale',
				name: 'Surreal Library'
			}
		]
	},
	{
		name: 'Samm Schwartz',
		workplace: [
			{
				address: '2025 Statement Street, Riverdale',
				name: 'Surreal Library'
			}
		]
	}
]

You can also use a graph query directly on a record instead of using a SELECT statement.

-- Get Samm's record ID
LET $samm = SELECT id FROM ONLY person WHERE name = 'Samm Schwartz' LIMIT 1;

-- Then just query from the record ID, no SELECT
$samm->works_at->place.{ address, floors, name };

Response
[
	{
		address: '2025 Statement Street, Riverdale',
		floors: 8,
		name: 'Surreal Library'
	}
]

Turning the -> arrow around to <- makes a graph query in the other direction. From the point of view of the place record, there is no ->works_at->person path because it’s not the place that works at the person , it’s the person that works at the place . Turning the arrows around will accomplish this.

The relation is still visually easy to follow, because place<-works_at<-person still shows that person leads into works_at and then into place . The only difference is that place is being used as the starting point now.

place:surreal_library<-works_at<-person.name;

Output: the names of the people that work at the library.

Response
[
	'Samm Schwartz',
	'Sara Bellum',
	'Lydia Wyndham'
]