Data Types

All Data Types

Property

Every created node or edge property has a data type. All the supported property data types are:

^[1] The precision is the total number of digits in the number, including both the integer and fractional parts (excl. the decimal point). The scale is the number of digits to the right of the decimal point.

Returned Data

After the data is retrieved from the database and processed, it can be returned with the following types:

Example graph:

NODE

Return the node whose name is Alice:

UQL
find().nodes({name == 'Alice'}) as n
return n{*}

Data structure of the node:

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

EDGE

Return the edge whose UUID is 53:

UQL
find().edges({_uuid == 53}) as e
return e{*}

Data structure of the edge:

e
{
	"uuid": 53,
	"schema": "studyAt",
	"from": "STU001",
	"to": "UNI001",
	"from_uuid": 1,
	"to_uuid": 1001,
	"values": {
		"start": 2001,
		"end": 2005
	}
}

PATH

Return the path from Alice to Oxford:

UQL
n({name == 'Alice'}).e().n({name == 'Oxford'}) as p
return p{*}

Date structure of the path:

p
{
	"length": 1,
	"nodes": [{
		"id": "STU001",
		"uuid": 1,
		"schema": "student",
		"values": {
			"name": "Alice",
			"age": 25
		}
	}, {
		"id": "UNI001",
		"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
		}
	}]
}

GRAPH

Return the graph formed by the path from Alice to Oxford:

UQL
n({name == 'Alice'}).e().n({name == 'Oxford'}) as p
return toGraph(collect(p))

Data structure of the graph:

toGraph(collect(p))
{
	"nodes": [{
		"id": "STU001",
		"uuid": 1,
		"schema": "student",
		"values": {
			"name": "Alice",
			"age": 25
		}
	}, {
		"id": "UNI001",
		"uuid": 1001,
		"schema": "university",
		"values": {
			"name": "Oxford"
		}
	}],
	"edges": [{
		"uuid": 53,
		"schema": "studyAt",
		"from": "STU001",
		"to": "UNI001",
		"from_uuid": 1,
		"to_uuid": 1001,
		"values": {
			"start": 2001,
			"end": 2005
		}
	}]
}

TABLE

Return the table of all nodes' ID and name properties:

UQL
find().nodes() as n
return table(n._id, n.name)

Result:

Data structure of the table:

table(n._id, n.name)
{
  "name": "table(n._id, n.name)",
  "alias": "table(n._id, n.name)",
  "headers": [
    "n._id",
    "n.name"
  ],
  "rows": [
    [
      "STU001",
      "Alice"
    ],
    [
      "UNI001",
      "Oxford"
    ]
  ]
}

ATTR

Return how many years Alice studied in Oxford:

UQL
find().edges({_uuid == 53}) as e
return e.end - e.start

Data structure of the value:

e.end - e.start
{
  "values": [
    4
  ]
}

NOTE

To specify a valid return format in the RETURN clause, please refer to the table provided here.

Null

In Ultipa Graph, null signifies the absence of a value for a property or a query result. It differs from 0 or an empty string. Null values are encountered in the following scenarios:

• During the insertion of new nodes or edges (insert(), insert().overwrite()), properties that are not specified are assigned null values.
• Upon creating a new property, existing nodes or edges of the corresponding schema are assigned null values for the newly created property.
• When a requested property does not exist, null values are returned instead.
• When using the OPTIONAL prefix for a query (find(), khop(), n().e().n(), etc.), if the query fails to yield results, null values are returned instead of nothing.

When null is involved in a conditional operation expression:

• If the judgement is definite, return true or false;
• otherwise, it returns null.

Any numerical computation (+, -, *, /, %) involving null will result in null.

Any aggregation operation (count(), sum(), max(), min(), avg(), stddev(), collect()) involving null will disregard rows with null values.

Functions and operators related to null:

• coalesce()
• ifnull()
• IS NULL
• IS NOT NULL.