# MS SQL Server
Through the MS SQL Server (opens new window) connector, Ontop is able to construct VKGs on SQL Server databases.
# Limitations & Exceptions
- RegEx SPARQL functions are not supported.
positionargument for the Flatten Lens cannot be used with SQLServer.
# Database Connection
The following shows the content of a sample
.properties file that can be used to connect Ontop to SQLServer:
jdbc.url = jdbc:sqlserver://localhost:1433;databaseName=defaultdatabase jdbc.user = user jdbc.password = password jdbc.driver = com.microsoft.sqlserver.jdbc.SQLServerDriver
# Nested Type Support
Nested data types are not supported by SQLServer. However, Ontop allows the usage of the flatten lens over string columns that contain JSON-encoded arrays. The output type of the flattened result column cannot be inferred.
position argument for flatten lenses cannot be used with SQLServer.
In case the flattened column is still a nested structure after the flatten operation is performed (e.g. for arrays of objects), SQLServer's JSON functions (opens new window) can be used to further work with them.