Apache AGE

It is a PostgreSQL extension that provides graph database functionality. That means we could have the relational database alongside the graph database

PostgreSQL

PostgreSQL is a powerful, open source object-relational database system with over 35 years of active development that has earned it a strong reputation for reliability, feature robustness, and performance.

PostgreSQL and Apache AGE

As mentioned before having the extension AGE on top of PostgreSQL allowing you to enable a new feature of the graph databases on top of the structured relational databases, i.e. adding the OpenCypher query language to the SQL language into a single language.

Need those or not?

• Do you need a flexible schema with relations?
• Need to quickly and easily store data and analyze the relationships among data, so you can better understand the myriad of possible outcomes?
• Simple querying

SELECT e.LastName, et.Description
FROM Employee AS e
JOIN EmployeeTerritory AS et ON (et.EmployeeID = e.EmployeeID)
JOIN Territory AS t ON (et.TerritoryID = t.TerritoryID);
Copy

Replaced with

MATCH (t:Territory)<-[:IN_TERRITORY]-(e:Employee)
RETURN t.description, collect(e.lastName);

• Visualization: you can view your graph using age-viewer
  

• Transactions support wrapped as it is inside a sql from statement, that feature is not widely supported by the rest available solutions of graph db

Example

Requirements

• PostgreSQL installed
• Apache AGE installed ###
• START A PSQL SESSION AND LOAD AGE AND SET SEARCH PATH

export $DB_NAME=test
psql $DB_NAME
test=# LOAD 'age';
LOAD
test=# SET search_path = ag_catalog, "$user", public;
SET

• Create graph

 SELECT * FROM create_graph('dev-graph');

• Create nodes and edge

test=#  SELECT * FROM cypher('dev-graph', $$
CREATE (n:DEVELOPER {name:"Mark", role:"Head of Engineering", department:"IT"})-[m:MANAGES]->(d:DEPARTMENT {name:"IT"}) return n, m, d 
$$) as (n agtype, m agtype, d agtype);

• Explanation:

  • (): Everything is wrapped with () is a node
  • []: Everything is wrapped with () is an edge
  • [str:] : str is an alias to hold the edge or if within () the node to mention it in the rest of the query
  • (str: LABEL): LABEL is the category or the label of the node
  • {}: called properties of json type that holds any info you want to add

• Query
  
  

test=#  SELECT * FROM cypher('dev-graph', $$
MATCH (n:DEVELOPER)-[m:MANAGES]->(d:DEPARTMENT) return n, d
$$) as (n agtype, d agtype);
                                                                    n                                                                     |                                           d                           

------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------
----------------
 {"id": 844424930131969, "label": "DEVELOPER", "properties": {"name": "Mark", "role": "Head of Engineering", "department": "IT"}}::vertex | {"id": 1407374883553281, "label": "DEPARTMENT", "properties": {"name":
 "IT"}}::vertex
(1 row)

Resources to learn more about Apache AGE:

• https://age.apache.org/
• https://sorrell.github.io/2020/12/10/Postgres-and-Apache-AGE.html
• https://bitnine.net/blog-postgresql/apache-age-journey-top-level/
• https://github.com/apache/age