Through the MySQL (opens new window) connector, Ontop is able to construct VKGs on MySQL databases.

# Limitations & Exceptions

  • String literals have to be encased in single quotes ('). Double quote string literals (") are not supported.
  • Accessing JSON object fields with the "dot operator" is not supported (see below).

# Database Connection

The following shows the content of a sample .properties file that can be used to connect Ontop to MySQL:

jdbc.url = jdbc:mysql://localhost:3306/defaultdatabase
jdbc.user = user
jdbc.password = password
jdbc.driver = com.mysql.cj.jdbc.Driver

# Nested Type Support

Ontop implements explicit compatibility with the MySQL type JSON which can be used with the flatten lens. However, it cannot infer the type of the flattened result column.

In case the flattened column is still a nested structure after the flatten operation is performed (e.g. for arrays of objects), MySQL's JSON functions (opens new window) can be used to further work with them.


Accessing object fields using the "arrow operator" is not supported.

Last Updated: 11/23/2023, 7:30:01 AM