Advanced Tutorial for Cypher (Part 2)

This Tutorial is extension of The tutorial Advanced Tutorial for Cypher Part (1)

Create Stored Procedure (1)

You can create Stored Procedure as follows:

• The fn_array_uniq function enters an array and returns a unique factor.
• IMMUTABLE represents the classification of the volatility of the procedure. Has the characteristics of calculating and processing returns as constants.
• STRICT returns a null value whenever the argument is null.
• The GENERATE_SERIES function takes** (start, stop, step interval)** as input variables and increments and decreases it to the units set in step interval
• The ARRAY_LOWER / ARRAY_UPPER function returns the lower/upper limit of the array dimension.

CREATE FUNCTION fn_array_uniq (anyarray)
RETURNS anyarray 
IMMUTABLE STRICT LANGUAGE SQL 
AS 
$$
SELECT ARRAY (
SELECT DISTINCT $1[i] 
FROM GENERATE_SERIES
(ARRAY_LOWER($1,1), ARRAY_UPPER($1,1)) AS g(i));
$$;

Create Stored Procedure (2)

You can create Stored Procedure as follows:

• Ids is a function that takes id of the unique vertex as a factor and appends it to the array.
• IF [Conditions] Then [True Execution Code] END IF [False Execution Code] Perform execution code when true or false, depending on the conditions.
• FOREACH [Execution Code] Performs an execution code with each row as a factor.
• LOOP [Repeat Execution Code] END LOOP Repeat the execution code in the Loop section until there is no input.

CREATE FUNCTION ids(vertex[]) RETURNS text[] AS $$
DECLARE
v vertex;    vids text[];
BEGIN
IF $1 IS NULL THEN
RETURN ARRAY[]::text[];
END IF;
FOREACH v IN ARRAY $1 
LOOP        vids = array_append(vids,
id(v)::text);
END LOOP;
vids = vids[2:];    RETURN vids;
END;
$$ LANGUAGE plpgsql;

Check the Fraud Ring

Explore the raid ring with Cypher Query using Stored Procedure.

SELECT cy.path
FROM (match path = (person:person)-[*..]-(person) with path,ids(nodes(path)) as node
    return path,length(fn_array_uniq(node)) as dcnt, length(node) as cnt) cy
WHERE cnt = dcnt

• Use the fn_array_uniq function to query the unique Node ID of the Path to be viewed as an array.
• Use the Ids function to extract only the Node IDs to consider and count and compare them.
• GraphPath that meets the previous conditions among the Paths inquired in the Match clause is printed and inquired.

Explore

• AGCloud
• Apache AGE
• Apache AGE Github Repo