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)
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