When you query JDBC, which is not MSSQL, you need to install and set the driver option.
So you need to get the JDBC driver for Oracle and install it first.
https://www.oracle.com/database/technologies/maven-central-guide.html
you need to know which one (from administrator or support=, and then in cluster config, you can install it from Maven.
driver = "your_driver_name"
remote_table = (spark.read
.format("jdbc")
.option("driver", driver)
...