Fingerprinting

The following functions calculate hashsums over nodes, relationship or the entire graph. It takes into account all properties, node labels and relationship types.

The algorithm used for hashing may change between APOC versions. So we can only compare hashing results of two entities/graphs from the same or from different graph using the very same apoc version.

The hashsum of a graph first calculates the hashsums for each node. This hashsum list is ordered and for each node the hashsum for all relationships and their end node are added. This approach provides independence of internal ids.

Optionally you can supply a list of propertyKeys that should be ignored on all nodes. This is useful if you store properties (like created=timestamp()) that should be ignored.

function name description

function name	description
`apoc.hashing.fingerprint(object, <list_of_props_to_ignore>)`	calculates a md5 hashsum over the object. It deals gracefully with ordering (in case of maps), scalars, arrays.
`apoc.hashing.fingerprinting(object, {conf})`	calculates a md5 hashsum over the object. It deals gracefully with ordering (in case of maps), scalars, arrays. Please check the `Fingerprinting configuration params` table for details
`apoc.hashing.graph(<list_of_props_to_ignore>)`	calculates a md5 hashsum over the full graph.

apoc.hashing.fingerprint(object, <list_of_props_to_ignore>)

calculates a md5 hashsum over the object. It deals gracefully with ordering (in case of maps), scalars, arrays.

apoc.hashing.fingerprinting(object, {conf})

calculates a md5 hashsum over the object. It deals gracefully with ordering (in case of maps), scalars, arrays. Please check the Fingerprinting configuration params table for details

apoc.hashing.graph(<list_of_props_to_ignore>)

calculates a md5 hashsum over the full graph.

Configuration parameters

Table 1. Fingerprinting configuration params
prop name	type	default	description
`digestAlgorithm`	ENUM	MD5	the digest algorithm used to create the fingerprint, we only support MD5 right now
`nodeAllowMap`	Map<K,V>	empty	a map where the key is the node Label and the value is a lists properties allowed
`relAllowMap`	Map<K,V>	empty	a map where the key is the rel type and the value is a lists properties allowed
`nodeDisallowMap`	Map<K,V>	empty	a DisallowMap map where the key is the node Label and the value is a lists properties disallowed
`relDisallowMap`	Map<K,V>	empty	a DisallowMap map where the key is the rel type and the value is a lists properties disallowed
`mapAllowList`	List	empty	a List used in case the input to the procedure is a map allowed
`mapDisallowList`	List	empty	a List used in case the input to the procedure is a map disallowed
`allNodesAllowList`	List	empty	a List used for properties common to all Nodes that you need to include in the fingerprint
`allRelsAllowList`	List	empty	a List used for properties common to all Relationships that you need to include in the fingerprint
`allNodesDisallowList`	List	empty	a List used for properties common to all Nodes that you need to exclude from the fingerprint
`allRelsDisallowList`	List	empty	a List used for properties common to all Relationships that you need to exclude from the fingerprint
`strategy`	Enum[EAGER, LAZY]	LAZY	define the behaviour in case the properties are not present for the specific node/relationship, see the `Fingerprinting strategy` paragraph

Fingerprinting strategy

n.b you cannot combine allow & disallow list for the same entity type, this means that for nodes/rels/maps you can specify allow or disallow with lists

In case the properties defined in the configuration are not present in the node and/or relationship you can define how the fingerprinting procedure must proceed with the process:

EAGER: it evaluates the whole node properties in order to create the fingerprint of the node/relationship
LAZY: it evaluates only the nodes/relationships provided in the configuration