Pattern Matching Tutorial
This tutorial shows you how to write and run pattern matching queries.
This tutorial assumes you have finished GSQL 101, and are familiar with the basics of defining a schema, loading data, and how to write basic queries.
What is a graph pattern?
A graph pattern is a traversal trace on the graph schema. A pattern can contain repeated steps. A pattern can be a linear trace, or a non-linear trace (tree, circle etc.).
For example, imagine a simple schema consisting of a Person vertex type and a Friendship edge type. A pattern could be a trace on this simple schema,
Person -(Friendship)- Person -(Friendship)- Personor, use *2 to denote the two consecutive Friendship edges,
Person -(Friendship*2)- PersonWhat is pattern matching?
Pattern matching is the process of finding subgraphs in a data graph that conform to a given query pattern.
Pattern matching provides a simple, declarative way to write queries to search for multi-hop pattern.
You can write multi-hop patterns in one query block (SELECT-FROM-WHERE) instead of several individual blocks.
The pattern can be fixed length or variable length (using Kleene stars for repeated hops), which significantly shortens the GSQL query length.
Follow the sequence below to learn how to write pattern matching queries in GSQL.