dfFromJdbc.scala

// Read JDBC Configuration from ENV Variables
val JDBC_URL: String = sys.env("JDBC_URL")
val JDBC_USERNAME: String = sys.env("JDBC_USERNAME")
val JDBC_PASSWORD: String = sys.env("JDBC_PASSWORD")
val JDBC_DRIVER: String = "com.mysql.jdbc.Driver"
val tableName: String = "k9JPOiHGpv.world_city_population"
 
// Define JDBC Read Options
val readOptions: Map[String, String] = Map(
  "driver" -> JDBC_DRIVER,
  "url" -> JDBC_URL,
  "user" -> JDBC_USERNAME,
  "password" -> JDBC_PASSWORD,
  "dbtable" -> tableName
)
 
// JDBC DataFrame with only one Partition - Spark Default JDBC Read Configuration
val mysql = (
  spark.read
  .options(readOptions)
  .format("jdbc")
  .load()
)