#! /usr/bin/python

import kivy
kivy.require("1.10.0")

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
import psycopg2

class TestDB(BoxLayout):

    def export_data(self):
        connection_str = "dbname = postgres user = postgres host = localhost      password=psswd"
        conn = psycopg2.connect(connection_str)
        cur = conn.cursor()

        cur.execute("INSERT INTO uniaxdb (patient_id,specimen_id) VALUES(
'test1','test2')")
        cur.close()

class TestDBApp(App):
    def build(self):
        return TestDB()

if __name__ == '__main__':
    TestDBApp().run()

<TestDB>:
    orientation: 'vertical'

    BoxLayout:

        Button:
            text: "export to DB"
            on_release: root.export_data()