apoc.meta.relTypeProperties

Procedure APOC Core

apoc.meta.relTypeProperties()

Signature

apoc.meta.relTypeProperties(config = {} :: MAP?) :: (relType :: STRING?, sourceNodeLabels :: LIST? OF STRING?, targetNodeLabels :: LIST? OF STRING?, propertyName :: STRING?, propertyTypes :: LIST? OF STRING?, mandatory :: BOOLEAN?, propertyObservations :: INTEGER?, totalObservations :: INTEGER?)

Input parameters

Name	Type	Default
config	MAP?	{}

Name

Type

Default

config

MAP?

{}

Config parameters

The procedure support the following config parameters:

Table 1. Config parameters
name	type	default	description
includeLabels	List<String>	[]	labels to include. Default is to include all labels
includeRels	List<String>	[]	relationship types to include. Default is to include all relationship types
excludeLabels	List<String>	[]	labels to exclude. Default is to not exclude any label
excludeRels	List<String>	[]	relationship types to exclude. Default is to not exclude any relationship type
sample	Long	1000	number of nodes to sample per label. See "Sampling" section below.
maxRels	Long	100	number of relationships to sample per relationship type

Sampling

Because the count stores return an incomplete picture of the data, we have to cross check the results with the actual data to filter out false positives.

We use a subset of the data to analyze by specifying the sample parameter (1000 by default).

Through this parameter, for each label we split data for each node-label into batches of (total / sample) ± rand where total is the total number of nodes with that label and rand is a number between 0 and total / sample / 10.

So, we pick a percentage of nodes with that label of roughly sample / total * 100% to check against. We pick the first node of each batch, and we analyze the properties and the relationships.

Table 2. Deprecated parameters
name	type	default	description
labels	List<String>	[]	deprecated, use `includeLabels`
rels	List<String>	[]	deprecated, use `includeRels`
excludes	List<String>	[]	deprecated, use `excludeLabels`

Output parameters

Name	Type
relType	STRING?
sourceNodeLabels	LIST? OF STRING?
targetNodeLabels	LIST? OF STRING?
propertyName	STRING?
propertyTypes	LIST? OF STRING?
mandatory	BOOLEAN?
propertyObservations	INTEGER?
totalObservations	INTEGER?

Name

Type

relType

STRING?

sourceNodeLabels

LIST? OF STRING?

targetNodeLabels

LIST? OF STRING?

propertyName

STRING?

propertyTypes

LIST? OF STRING?

mandatory

BOOLEAN?

propertyObservations

INTEGER?

totalObservations

INTEGER?

Usage Examples

The examples in this section are based on the following sample graph:

CREATE (Keanu:Person {name:'Keanu Reeves', born:1964})
CREATE (TomH:Person {name:'Tom Hanks', born:1956})
CREATE (LillyW:Person {name:'Lilly Wachowski', born:1967})

CREATE (TheMatrix:Movie {title:'The Matrix', released:1999, tagline:'Welcome to the Real World'})
CREATE (TheMatrixReloaded:Movie {title:'The Matrix Reloaded', released:2003, tagline:'Free your mind'})
CREATE (TheMatrixRevolutions:Movie {title:'The Matrix Revolutions', released:2003, tagline:'Everything that has a beginning has an end'})
CREATE (SomethingsGottaGive:Movie {title:"Something's Gotta Give", released:2003})
CREATE (TheDevilsAdvocate:Movie {title:"The Devil's Advocate", released:1997, tagline:'Evil has its winning ways'})

CREATE (YouveGotMail:Movie {title:"You've Got Mail", released:1998, tagline:'At odds in life... in love on-line.'})
CREATE (SleeplessInSeattle:Movie {title:'Sleepless in Seattle', released:1993, tagline:'What if someone you never met, someone you never saw, someone you never knew was the only someone for you?'})
CREATE (ThatThingYouDo:Movie {title:'That Thing You Do', released:1996, tagline:'In every life there comes a time when that thing you dream becomes that thing you do'})
CREATE (CloudAtlas:Movie {title:'Cloud Atlas', released:2012, tagline:'Everything is connected'})

CREATE (Keanu)-[:ACTED_IN {roles:['Neo']}]->(TheMatrix)
CREATE (Keanu)-[:ACTED_IN {roles:['Neo']}]->(TheMatrixReloaded)
CREATE (Keanu)-[:ACTED_IN {roles:['Neo']}]->(TheMatrixRevolutions)
CREATE (Keanu)-[:ACTED_IN {roles:['Julian Mercer']}]->(SomethingsGottaGive)
CREATE (Keanu)-[:ACTED_IN {roles:['Kevin Lomax']}]->(TheDevilsAdvocate)

CREATE (TomH)-[:ACTED_IN {roles:['Joe Fox']}]->(YouveGotMail)
CREATE (TomH)-[:ACTED_IN {roles:['Sam Baldwin']}]->(SleeplessInSeattle)
CREATE (TomH)-[:ACTED_IN {roles:['Mr. White']}]->(ThatThingYouDo)
CREATE (TomH)-[:ACTED_IN {roles:['Zachry', 'Dr. Henry Goose', 'Isaac Sachs', 'Dermot Hoggins']}]->(CloudAtlas)

CREATE (LillyW)-[:DIRECTED]->(TheMatrix);

We can return the metadata of the database from a sample of the database contents, by running the following query:

CALL apoc.meta.relTypeProperties();

Table 3. Results
relType	sourceNodeLabels	targetNodeLabels	propertyName	propertyTypes	mandatory	propertyObservations	totalObservations
":`ACTED_IN`"	["Person"]	["Movie"]	"roles"	["StringArray"]	FALSE	9	9
":`DIRECTED`"	["Person"]	["Movie"]	NULL	NULL	FALSE	0	1

We can return metadata for a subset of relationship types by specifying the rels config parameter. The following returns the metadata for the ACTED_IN label:

CALL apoc.meta.relTypeProperties({rels: ["ACTED_IN"]});

Table 4. Results
relType	sourceNodeLabels	targetNodeLabels	propertyName	propertyTypes	mandatory	propertyObservations	totalObservations
":`ACTED_IN`"	["Person"]	["Movie"]	"roles"	["StringArray"]	FALSE	9	9

We can control the number of relationships sampled by specifying the maxRels parameter. The following returns metadata based on sampling up to 3 relationships per relationship type:

CALL apoc.meta.relTypeProperties({maxRels: 3});

Table 5. Results
relType	sourceNodeLabels	targetNodeLabels	propertyName	propertyTypes	mandatory	propertyObservations	totalObservations
":`ACTED_IN`"	["Person"]	["Movie"]	"roles"	["StringArray"]	FALSE	3	9
":`DIRECTED`"	["Person"]	["Movie"]	NULL	NULL	FALSE	0	1