All Data Types

Data Types of Property

^[1]Precision is the sum of the lengths of integers and decimals, excluding the point
^[2]Scale is the lenght of decimals

Data Types of RETURN

Examples:

The NODE structure of Alice in the above chart:

{
	"id": "STU001",
	"uuid": 1,
	"schema": "student",
	"values": {
		"name": "Alice",
		"age": 25
	}
}

The EDGE structure in the above chart:

{
	"uuid": 53,
	"schema": "studyAt",
	"from": "STU001",
	"to": "UNV001",
	"from_uuid": 1,
	"to_uuid": 1001,
	"values": {
		"start": 2001,
		"end": 2005
	}
}

The PATH structure representing 'Alice studies at Oxford' in the above chart:

{
	"length": 1,
	"nodes": [{
		"id": "STU001",
		"uuid": 1,
		"schema": "student",
		"values": {
			"name": "Alice",
			"age": 25
		}
	}, {
		"id": "UNV001",
		"uuid": 1001,
		"schema": "university",
		"values": {
			"name": "Oxford"
		}
	}],
	"edges": [{
		"uuid": 53,
		"schema": "studyAt",
		"from": "STU001",
		"to": "UNV001",
		"from_uuid": 1,
		"to_uuid": 1001,
		"values": {
			"start": 2001,
			"end": 2005
		}
	}]
}

Consider a tabular structure with alias group_stats:

| group_name | count |
|------------|-------|
| green      |   5   |
| red        |   1   |
| yellow     |   2   |

The TABLE structure is:

{
	"name": "group_stats",
	"headers": ["group_name", "count"],
	"rows": [
		["green", 5],
		["red", 1],
		["yellow", 2]
	]
}

Regarding how to specify a valid return format in RETURN clause, please read the table at the end of documentation RETURN.

About NULL

null is produced when:

• inserting a new metadata (insert()、insert().overwrite()), those properties not provided will be null
• creating a new property under a schema, this property of those metadata that already exist will be null
• returning a non-existent property in a RETURN clause, null will be returned
• no result found for a query (find()、khop()、template) that uses prefix OPTIONAL, the metadata returned will be null

When null participates in a conditional judgement and if:

• it is sure about the result, then return this result
• it is NOT sure about the result, then return null

Any numerical computation (+, -, *, /, %) participated by null will return null.

Any aggregation operation (count(), sum(), max(), min(), avg(), stddev(), collect()) participated by null will ignore the rows with null.

Regarding functions and operators related with null please read documentations coalesce()，ifnull()，IS NULL，IS NOT NULL.