apoc.meta.relTypeProperties

This procedure is not considered safe to run from multiple threads. It is therefore not supported by the parallel runtime (introduced in Neo4j 5.13). For more information, see the Cypher Manual → Parallel runtime.

Details
Syntax	`apoc.meta.relTypeProperties([ config ]) :: (relType, sourceNodeLabels, targetNodeLabels, propertyName, propertyTypes, mandatory, propertyObservations, totalObservations)`
Description	Examines the full graph and returns a table of metadata with information about the `RELATIONSHIP` values therein.
Input arguments	Name	Type	Description
Input arguments	`config`	`MAP`	`{ includeLabels = [] :: LIST<STRING>, includeRels = [] :: LIST<STRING>, excludeLabels = [] :: LIST<STRING>, excludeRels = [] :: LIST<STRING>, sample = 1000 :: INTEGER, maxRels = 100 :: INTEGER }`. The default is: `{}`.
Return arguments	Name	Type	Description
	`relType`	`STRING`	The type of the relationship.
	`sourceNodeLabels`	`LIST<STRING>`	The labels belonging to the start node.
	`targetNodeLabels`	`LIST<STRING>`	The labels belonging to the end node.
	`propertyName`	`STRING`	The name of the property.
	`propertyTypes`	`LIST<STRING>`	The types this property has.
	`mandatory`	`BOOLEAN`	Whether or not this property exists on all nodes of the given type.
	`propertyObservations`	`INTEGER`	The number of times this property was observed.
	`totalObservations`	`INTEGER`	The number of times the label was seen.

Config parameters

This procedure supports the following config parameters:

Config parameters
Name	Type	Default	Description
`includeLabels`	`LIST<STRING>`	[]	Node labels to include. Default is to include all node labels.
`includeRels`	`LIST<STRING>`	[]	Relationship types to include. Default is to include all relationship types.
`excludeLabels`	`LIST<STRING>`	[]	Node labels to exclude. Default is to include all node labels.
`excludeRels`	`LIST<STRING>`	[]	Relationship types to exclude. Default is to include all relationship types.
`sample`	`INTEGER`	1000	Number of nodes to sample. Setting `sample` to `-1` will remove sampling.
`maxRels`	`INTEGER`	100	Number of relationships to read per sampled node.

Sampling

Specify the sample parameter (1000 by default) to analyze a subset of the data.

The sample, along with the count of nodes for each label, is used to calculate a skip value. Since this value is generated using a random number generator, results obtained through the sampling method may vary between subsequent runs.

Example 1. Calculating skip count for data sampling

If a database contains 500 nodes with the label Foo label, the skip count for that label is calculated as follows:

The skip count per node label is determined by generating a random number between (totalNodesForLabel / sample) ± 0.1.

Sample 10: skipCount = 500 / 10 = 50
The resulting skip count will be between 45 and 55.

Sample 50: skipCount = 500 / 50 = 10
The resulting skip count will be between 9 and 11.

Sample 100: skipCount = 500 / 100 = 5
The resulting skip count will be 5.

The skip count represents the number of nodes skipped before one is examined. For instance, with a skip count of 5, every 5th node is examined. Consequently, a higher sample number results in more nodes being sampled.

To stop sampling set sample: -1.

Deprecated parameters
Name	Type	Default	Description
`labels`	`LIST<STRING>`	[]	Deprecated, use `includeLabels`.
`rels`	`LIST<STRING>`	[]	Deprecated, use `includeRels`.
`excludes`	`LIST<STRING>`	[]	Deprecated, use `excludeLabels`.

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();

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"]});

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});

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