openCypher: Adding Property Graph Extensions to SQL Using Graph Query Procedures

SQL/Graph Query
Procedures: an early draft
oCIG 4 Presentation, 2017-08-17
Peter Furniss, Neo4j

Motivation
Don’t distort SQL with graph querying capabilities
Instead, follow precedents set by SQL/XML and SQL/JSON:
Extend SQL with a new GRAPH_REFERENCE data type (which is opaque)
Extend SQL with the ability to invoke procedures to undertake graph query
processing

Single and dual engine architecture for the implementation of a graph
query engine

Graph query procedures: overview
1) GRAPH_QUERY procedure:
Returns one or more graphs as GRAPH_REFERENCES
Returns one or more table columns
2) GRAPH_TABLE procedure:
Returns one or more table columns only

Graph query procedures: inputs
Mandatory inputs:
Graph inputs: one or multiple GRAPH_REFERENCES
Query specification: a string which is a query statement for the target graph
query language
Optional inputs:
Driver table: A table expression, the types of whose columns are capable of
being processed by the graph query engine/language
Query parameters: A list of named scalar values

Graph query procedures: results
GRAPH_QUERY and GRAPH_TABLE return:
Result table: a named table, containing the data returned by the procedure
after the graph query engine has processed the graph query specified in the
“Query specification” parameter

Example: Creating and returning a graph using
the GRAPH_QUERY procedure

Step 1: Defining the input graph
Assume the following table, SALES_GRAPHS:

Step 1: Defining the input graph
Query snippet:
WITH QUARTERLY_SALES_DETAILS_GRAPH
AS SELECT RESULT_TABLE_FROM_CYPHER_QUERY_1.*
FROM SALES_GRAPHS G
GRAPH_QUERY
(GRAPH_INPUT =>
(SELECT SALES_GRAPH
FROM G
WHERE G.NAME = 'SalesDetail'
AND G.YEAR_QUARTER IS NULL),

Step 2: Defining the graph query
Query snippet:
QUERY_SPECIFICATION =>
OPAQUE endCypherQuery_1
with graph SalesDetail
match (p:Product)-[r:IN]->(o:Order)<-[:HAS]-(s:Store)-[:IN]->(reg:Region)
where datein(o.date, $YEAR_QUARTER_PARAMETER)
return new graph QuarterlySalesDetail
endCypherQuery_1

Step 3: Passing parameters
We assume the existence of a parameter @0 which has been set to ‘2017Q3’
Query snippet:
PASSING @0 AS YEAR_QUARTER_PARAMETER

Step 4: Returning the new graph from GRAPH_QUERY
Query snippet:
COLUMNS
(QuarterlySalesDetail GRAPH_REFERENCE AS SALES_DETAIL)
...
AS RESULT_TABLE_FROM_CYPHER_QUERY_1

Step 5: Post-processing tasks
Query snippet:
INSERT INTO SALES_GRAPHS
(NAME,
YEAR_QUARTER,
SALES_GRAPH)
VALUES
('SalesDetail',
@0,
(SELECT DISTINCT SALES_DETAIL
FROM QUARTERLY_SALES_DETAILS_GRAPH))

After execution, the SALES_GRAPHS table contains:

Putting it all together: the full query
WITH QUARTERLY_SALES_DETAILS_GRAPH
AS SELECT RESULT_TABLE_FROM_CYPHER_QUERY_1.*
FROM SALES_GRAPHS G
GRAPH_QUERY
(INPUT_GRAPH =>
(SELECT SALES_GRAPH
FROM G
WHERE G.NAME = 'SalesDetail'
AND G.YEAR_QUARTER IS NULL), -- the OLTP
“perpetual” graph
QUERY_SPECIFICATION =>
OPAQUE endCypherQuery_1 //delimit graph query
// Cypher query 1: extract a quarterly snapshot of sales
with graph SalesDetail
match
(p:Product)-[r:IN]->(o:Order)<-[:HAShas]-(s:Store)-[:IN]->(r
eg:Region)
where datein(o.date, $YEAR_QUARTER_PARAMETER)
return new graph QuarterlySalesDetail
endCypherQuery_1
<query continues in right box>
PASSING @0 AS YEAR_QUARTER_PARAMETER
COLUMNS
(QuarterlySalesDetail GRAPH_REFERENCE
AS SALES_DETAIL)
)
AS RESULT_TABLE_FROM_CYPHER_QUERY_1
INSERT INTO SALES_GRAPHS -- store graph reference
for quarterly SALES_DETAIL graph
(NAME,
YEAR_QUARTER,
SALES_GRAPH)
VALUES
('SalesDetail',
@0,
(SELECT DISTINCT SALES_DETAIL
FROM QUARTERLY_SALES_DETAILS_GRAPH))

openCypher: Adding Property Graph Extensions to SQL Using Graph Query Procedures

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openCypher: Adding Property Graph Extensions to SQL Using Graph Query Procedures