def connect_to_oracle_db(spark_session, db_query):
    return spark_session.read
        .format("jdbc")
        .option("url", "jdbc:oracle:thin:@//<host>:<port>/<srvice_name")
        .option("user", "<user>")
        .option("password", "<pass>")
        .option("dbtable", db_query)
        .option("driver", "oracle.jdbc.driver.OracleDriver")

def run(self):
    all_schemes  = <list of all available schemes>
    for str_schema in all_schemes:
        db_query = "(Select * from " + str_schema + ".TABLE1) TABLE1_DATA"
        df_table1 = slef.connect_to_oracle_db(db_query ).load()
        # process df_table1