---
parser: v2
author_name: Markus Fath
author_profile: https://github.com/fath-markus
auto_validation: true
time: 15
tags: [tutorial>beginner, products>sap-hana, products>sap-hana-cloud, products>sap-hana\,-express-edition, programming-tool>sql]
primary_tag: products>sap-hana
slug: hana-graph-overview-graphscript
canonical_url: https://developers.sap.com/tutorials/hana-graph-overview-graphscript
---

# Complex Algorithms Using GraphScript
<!-- description --> Learn what is GraphScript, and then build complex algorithms in SAP HANA Graph using GraphScript.

## Prerequisites
 - You completed [Pattern Matching using OpenCypher in SQL](hana-graph-overview-pattern-matching-sql)

## You will learn
  - What GraphScript is
  - How to create and execute GraphScript procedures

---

### What GraphScript is


GraphScript is a high-level, powerful domain-specific language. GraphScript is specifically designed to ease the development and integration of complex graph algorithms into the existing data management workflow.

 For more please refer to [online documentation for SAP HANA Cloud](https://help.sap.com/viewer/11afa2e60a5f4192a381df30f94863f9/2020_04_QRC/en-US/47b72452f48f4ca490fbffcb5ca31f92.html).


### Call built-in algorithm from GraphScript


In the SQL Console paste and execute following code.

```sql
SET SCHEMA "SKIING";

--DROP TYPE "TT_NODES" CASCADE;
CREATE TYPE "TT_NODES" AS TABLE ("node_id" INTEGER, "name" NVARCHAR(16));

--DROP PROCEDURE "NHOOD";
CREATE OR REPLACE PROCEDURE "NHOOD"(
	IN startV INTEGER,
	IN minDepth INTEGER,
	IN maxDepth INTEGER,
	OUT res "TT_NODES")
LANGUAGE GRAPH READS SQL DATA AS
BEGIN
  GRAPH g = Graph("SKIING");
  VERTEX v_s = Vertex(:g, :startV);
  MULTISET<VERTEX> ms_n = Neighbors(:g, :v_s, :minDepth, :maxDepth);
  res = SELECT :v."node_id", :v."name" FOREACH v IN :ms_n;
END;
```

This creates an `NHOOD` object in **Procedures**.

![Create first GraphScript procedure](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-graph-overview-graphscript/010b.png)

Run `CALL "NHOOD"` with different parameters to check results.

```sql
CALL "SKIING"."NHOOD"(10, 1, 1, ?);
```

![First results](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-graph-overview-graphscript/020b.png)



### Custom traverse algorithm


In the SQL Console paste and execute following code. It creates a procedure to calculate shortest path distances to stations with restaurants.

```sql
SET SCHEMA "SKIING";

--DROP TYPE "TT_RESTAURANTS";
CREATE TYPE "TT_RESTAURANTS" AS TABLE ("node_id" INTEGER, "distance" INTEGER, "hops" BIGINT);

--DROP PROCEDURE "NEAREST_RESTAURANT";
CREATE OR REPLACE PROCEDURE "NEAREST_RESTAURANT"(IN startV INT, OUT res "TT_RESTAURANTS")
LANGUAGE GRAPH READS SQL DATA AS
BEGIN
	GRAPH g = Graph("SKIING");
	VERTEX v_s = Vertex(:g, :startV);
	MULTISET<Vertex> rests = v IN Vertices(:g) WHERE :v."restaurant" == N'TRUE';
	ALTER g ADD TEMPORARY VERTEX ATTRIBUTE (INT "distance" = 0);
	ALTER g ADD TEMPORARY VERTEX ATTRIBUTE (BIGINT "hops" = 0L);
	FOREACH rest in :rests {
		VERTEX v_rest = Vertex(:g, :rest."node_id");
		WeightedPath<INT> p = Shortest_Path(:g, :v_s, :v_rest, (Edge conn) => INTEGER { return :conn."length"; } );
		rest."hops" = Length(:p);
		rest."distance" = Weight(:p);
	}
	res = SELECT :v."node_id", :v."distance", :v."hops" FOREACH v IN :rests;
END;
```

This creates an `NEAREST_RESTAURANT` object in **Procedures**. Right click on the procedure name and pick **Generate CALL Statement With UI**.

![Generate call with UI](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-graph-overview-graphscript/030b.png)

Procedure's call statement is generated. Provide input value `15` and click **Run**.

![Run generated procedure](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-graph-overview-graphscript/040b.png)

When the graph script is executed, then the result is displayed. It shows a shortest distance in meters to each station with the restaurant plus number of hops to get there.

![GraphScript results](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-graph-overview-graphscript/050b.png)

What is the shortest path distance in meters from station `15` to station `3`?



---