neo4j glossary of terms Flashcards
allocator (cluster)
A component in the cluster that allocates databases to servers according to the topology constraints specified and an allocation strategy.
asynchronous replication (cluster)
Asynchronous replication is used by secondary copies to poll for new transactions, which means they cannot be guaranteed to have received the most recent transactions. This enables efficient scale-out of read-performance.
Aura instance
A fully-managed database represented by a single DBID, that is running in the Neo4j Aura cloud.
auto-commit transaction
An automatically committed transaction that contains a single query.
Bolt protocol
Bolt is a protocol used for interaction between Neo4j instances and drivers.
bookmark
A marker the client can request from the cluster to ensure that it is able to read its own writes so that the application’s state is consistent and only databases that have a copy of the bookmark are permitted to respond.
category (Bloom)
A category is based on a node label and is defined in a Perspective as a way of visually distinguishing nodes with the same label(s).
causal consistency
All servers in a cluster agree on the order in which transactions take place. The position of a server on the causal chain can be guaranteed using a bookmark.
cluster
A Neo4j DBMS that spans multiple servers working together to increase fault tolerance and/or read scalability. Databases on a cluster may be configured to replicate across servers in the cluster thus achieving read scalability or high availability.
client application
Software that interacts with a Neo4j server.
commit
A commit is the successful completion of a transaction, which ensures durability of any changes made. For more details, visit Operations Manual → Transaction management.
Composite database
Composite databases are the means to access partitioned graph data with a single Cypher query.
constraint
Constraints are sets of data modeling rules that ensure the data is consistent and reliable.
Core server (Neo4j 4)
A server in a cluster operating in read/write mode. This is replaced in Neo4j 5 by the database-level configuration of primary and secondary databases.
Cypher®
Neo4j’s graph query language.
data model
A data model defines how information is organized in a database. A good data model will make querying and understanding your data easier. In Neo4j, the data models have a graph structure.
database
A database is a container used by the DBMS to manage and store graph data. The physical structure of data is controlled by the database.
database vs graph
Databases are the physical containers of graph data. Graphs are the logical structure of data in Neo4j.
Database Management System
Database Management System, or DBMS, capable of managing multiple databases. A DBMS may run on a single server, or span several servers configured as a cluster.
database schema
The prescribed property existence and datatypes for nodes and relationships.
deallocate (cluster)
An act of removing a database from a server or a server from a cluster without loss of data or reduced fault tolerance.
degree (of a node)
The number of relationships of a specific node; loops are counted twice.
disaster recovery (cluster)
A manual intervention to restore availability of a cluster, or databases within a cluster.
driver
A software library that provides access to Neo4j from a particular programming language.
election (cluster)
In the event that the Raft leader becomes unresponsive, followers automatically trigger an election and vote for a new leader.
entity
A node or a relationship.
expression (Cypher)
A component of a Cypher query which produces values. It may be used in projections, as a predicate, or when setting properties on graph elements.