import mysql.connector


def main():
    connection = mysql.connector.connect(
        host='ensembldb.ensembl.org',
        user='anonymous',
        password='',
        port='3337')

    sql = """
    SELECT stable_id, biotype
    FROM homo_sapiens_core_85_37.transcript;
    """
    try:
        cursor = connection.cursor()
        cursor.execute(sql)
        while True:
            rows = cursor.fetchmany(1000)
            if not rows:
                break
            for row in rows:
                yield row
    finally:
        cursor.close()
        connection.close()


for line in main():
    print(line)