Create a graph database and run some pattern matching queries using T-SQL

Applies to: SQL Server 2017 (14.x) and later Azure SQL Database Azure SQL Managed Instance

This sample provides a Transact-SQL script to create a graph database with nodes and edges and then use the new MATCH clause to match some patterns and traverse through the graph. This sample script will work on both Azure SQL Database and SQL Server 2017 (14.x)

Sample Schema

This sample creates a graph schema, as showed in Figure 1, for a hypothetical social network that has People, Restaurant and City nodes. These nodes are connected to each other using Friends, Likes, LivesIn and LocatedIn edges.

Figure 1: Sample schema with restaurant, city, person nodes and LivesIn, LocatedIn, Likes edges.

Sample Script

-- Create a graph demo database
IF NOT EXISTS (SELECT * FROM sys.databases WHERE NAME = 'graphdemo')
	CREATE DATABASE GraphDemo;
GO

USE GraphDemo;
GO

-- Create NODE tables
CREATE TABLE Person (
  ID INTEGER PRIMARY KEY,
  name VARCHAR(100)
) AS NODE;

CREATE TABLE Restaurant (
  ID INTEGER NOT NULL,
  name VARCHAR(100),
  city VARCHAR(100)
) AS NODE;

CREATE TABLE City (
  ID INTEGER PRIMARY KEY,
  name VARCHAR(100),
  stateName VARCHAR(100)
) AS NODE;

-- Create EDGE tables.
CREATE TABLE likes (rating INTEGER) AS EDGE;
CREATE TABLE friendOf AS EDGE;
CREATE TABLE livesIn AS EDGE;
CREATE TABLE locatedIn AS EDGE;

-- Insert data into node tables. Inserting into a node table is same as inserting into a regular table
INSERT INTO Person (ID, name)
	VALUES (1, 'John')
		 , (2, 'Mary')
		 , (3, 'Alice')
		 , (4, 'Jacob')
		 , (5, 'Julie');

INSERT INTO Restaurant (ID, name, city)
	VALUES (1, 'Taco Dell','Bellevue')
		 , (2, 'Ginger and Spice','Seattle')
		 , (3, 'Noodle Land', 'Redmond');

INSERT INTO City (ID, name, stateName)
	VALUES (1,'Bellevue','WA')
		 , (2,'Seattle','WA')
		 , (3,'Redmond','WA');

-- Insert into edge table. While inserting into an edge table,
-- you need to provide the $node_id from $from_id and $to_id columns.
/* Insert which restaurants each person likes */
INSERT INTO likes
	VALUES ((SELECT $node_id FROM Person WHERE ID = 1), (SELECT $node_id FROM Restaurant WHERE ID = 1), 9)
		 , ((SELECT $node_id FROM Person WHERE ID = 2), (SELECT $node_id FROM Restaurant WHERE ID = 2), 9)
		 , ((SELECT $node_id FROM Person WHERE ID = 3), (SELECT $node_id FROM Restaurant WHERE ID = 3), 9)
		 , ((SELECT $node_id FROM Person WHERE ID = 4), (SELECT $node_id FROM Restaurant WHERE ID = 3), 9)
		 , ((SELECT $node_id FROM Person WHERE ID = 5), (SELECT $node_id FROM Restaurant WHERE ID = 3), 9);

/* Associate in which city live each person*/
INSERT INTO livesIn
	VALUES ((SELECT $node_id FROM Person WHERE ID = 1), (SELECT $node_id FROM City WHERE ID = 1))
		 , ((SELECT $node_id FROM Person WHERE ID = 2), (SELECT $node_id FROM City WHERE ID = 2))
		 , ((SELECT $node_id FROM Person WHERE ID = 3), (SELECT $node_id FROM City WHERE ID = 3))
		 , ((SELECT $node_id FROM Person WHERE ID = 4), (SELECT $node_id FROM City WHERE ID = 3))
		 , ((SELECT $node_id FROM Person WHERE ID = 5), (SELECT $node_id FROM City WHERE ID = 1));

/* Insert data where the restaurants are located */
INSERT INTO locatedIn
	VALUES ((SELECT $node_id FROM Restaurant WHERE ID = 1), (SELECT $node_id FROM City WHERE ID =1))
		 , ((SELECT $node_id FROM Restaurant WHERE ID = 2), (SELECT $node_id FROM City WHERE ID =2))
		 , ((SELECT $node_id FROM Restaurant WHERE ID = 3), (SELECT $node_id FROM City WHERE ID =3));

/* Insert data into the friendOf edge */
INSERT INTO friendOf
	VALUES ((SELECT $NODE_ID FROM Person WHERE ID = 1), (SELECT $NODE_ID FROM Person WHERE ID = 2))
		 , ((SELECT $NODE_ID FROM Person WHERE ID = 2), (SELECT $NODE_ID FROM Person WHERE ID = 3))
		 , ((SELECT $NODE_ID FROM Person WHERE ID = 3), (SELECT $NODE_ID FROM Person WHERE ID = 1))
		 , ((SELECT $NODE_ID FROM Person WHERE ID = 4), (SELECT $NODE_ID FROM Person WHERE ID = 2))
		 , ((SELECT $NODE_ID FROM Person WHERE ID = 5), (SELECT $NODE_ID FROM Person WHERE ID = 4));


-- Find Restaurants that John likes
SELECT Restaurant.name
FROM Person, likes, Restaurant
WHERE MATCH (Person-(likes)->Restaurant)
AND Person.name = 'John';

-- Find Restaurants that John's friends like
SELECT Restaurant.name
FROM Person person1, Person person2, likes, friendOf, Restaurant
WHERE MATCH(person1-(friendOf)->person2-(likes)->Restaurant)
AND person1.name='John';

-- Find people who like a restaurant in the same city they live in
SELECT Person.name
FROM Person, likes, Restaurant, livesIn, City, locatedIn
WHERE MATCH (Person-(likes)->Restaurant-(locatedIn)->City AND Person-(livesIn)->City);

-- Find friends-of-friends-of-friends, excluding those cases where the relationship "loops back".
-- For example, Alice is a friend of John; John is a friend of Mary; and Mary in turn is a friend of Alice.
-- This causes a "loop" back to Alice. In many cases, it is necessary to explicitly check for such loops and exclude the results.
SELECT CONCAT(Person.name, '->', Person2.name, '->', Person3.name, '->', Person4.name)
FROM Person, friendOf, Person as Person2, friendOf as friendOffriend, Person as Person3, friendOf as friendOffriendOfFriend, Person as Person4
WHERE MATCH (Person-(friendOf)->Person2-(friendOffriend)->Person3-(friendOffriendOfFriend)->Person4)
AND Person2.name != Person.name
AND Person3.name != Person2.name
AND Person4.name != Person3.name
AND Person.name != Person4.name;

Clean Up

Clean up the schema and database created for the sample.

USE graphdemo;
go

DROP TABLE IF EXISTS likes;
DROP TABLE IF EXISTS Person;
DROP TABLE IF EXISTS Restaurant;
DROP TABLE IF EXISTS City;
DROP TABLE IF EXISTS friendOf;
DROP TABLE IF EXISTS livesIn;
DROP TABLE IF EXISTS locatedIn;

USE master;
go
DROP DATABASE graphdemo;
go

Script explanation

This script uses the new T-SQL syntax to create node and edge tables. Shows how to insert data into node and edge tables using INSERT statement and also shows how to use MATCH clause for pattern matching and navigation.

Command	Notes
CREATE TABLE (Transact-SQL)	Create graph node or edge table
INSERT (Transact-SQL)	Insert into a node or edge table
MATCH (Transact-SQL)	Use MATCH to match a pattern or traverse through the graph