Question

我有一个arduino uno和temp36。我从使用Python的arduino串行监视器读取传感器值。有用！！

但是我不能使用Python在创建的MySQL表中插入，我不知道为什么。我没有错误或警告。

import serial
import time
import MySQLdb

dbhost = 'localhost'
dbname = 'test'
dbuser = 'X'
dbpass = 'Y'
ser = serial.Serial('COM7',9600,timeout=1) # On Ubuntu systems, /dev/ttyACM0 is the default path to the serial device on Arduinos, yours is likely different.
while 1:
time.sleep(1)
the_goods = ser.readline()
str_parts = the_goods.split(' ')
conn = MySQLdb.connect (host = dbhost,
                user = dbuser,
                passwd = dbpass,
                db = dbname)
cursor = conn.cursor ()
sql = "INSERT INTO arduino_temp (temperature) VALUES ('%s');" % (str_parts[0])
print "Number of rows inserted: %d" % cursor.rowcount
try:
    cursor.execute(sql)
except:
    pass
cursor.close ()
conn.autocommit=True
conn.close ()
print the_goods

我做错了吗？

SQL表中的那些值需要在php中进行绘图（实时绘图）

硬件：Windows 7，Python 2.7，Python编辑器：Pyscripter，arduino uno，MySQL Workbench

Answer 1

执行sql语句后必须提交：

cursor.execute(sql)
cursor.commit()

建立连接后

或设置autocommit=True。

Answer 2

如果打开数据库连接，它最初采用autocommit=False模式，因此在执行SQL语句后，您必须commit()它。在例外情况下也不要pass。这样你就不会看到问题了。您可以将异常记录到文件中。在执行INSERT语句之前，还要使用cursor.rowcount。在它之后使用它。

您的评论似乎没有定义arduino_temp数据库。我没有MySQL数据库，但我已经使用PostgreSQL和ODBC驱动程序测试了这样的代码。您可以使用它来测试数据库和驱动程序：

import MySQLdb
import traceback


def ensure_table(conn):
    cursor = conn.cursor()
    try:
        cursor.execute('SELECT COUNT(*) FROM arduino_temp')
        for txt in cursor.fetchall():
            print('Number of already inserted temepratures: %s' % (txt[0]))
    except:
        s = traceback.format_exc()
        print('Problem while counting records:\n%s\n' % (s))
        print('Creating arduino_temp table ...')
        # table arduino_temp does not exist
        # you have to define table there
        # you will probably have to add some columns as:
        #  test_id SERIAL primary key,
        #  test_date timestamp default CURRENT_TIMESTAMP,
        # and add index on test_date
        cursor.execute('CREATE TABLE arduino_temp (temperature integer)')
        print('table created')
    cursor.close()


def insert_temperature(conn, temperature):
    cursor = conn.cursor()
    #cursor.execute("INSERT INTO arduino_temp (temperature) VALUES (?)", (temperature, ))
    #cursor.execute("INSERT INTO arduino_temp (temperature) VALUES (%s)", (temperature, ))
    cursor.execute("INSERT INTO arduino_temp (temperature) VALUES (%d)" % (int(temperature)))
    print("Number of rows inserted: %d" % (cursor.rowcount))
    conn.commit()
    cursor.close()


def main():
    # ...
    conn = MySQLdb.connect (host = dbhost, user = dbuser, passwd = dbpass, db = dbname)
    #conn = pyodbc.connect('DSN=isof_test;uid=dbuser;pwd=dbpass')
    ensure_table(conn)
    insert_temperature(conn, 10)


main()

如果您在使用数据库创建测试代码时遇到问题并使用小功能。您的代码是串行接口的混合读取温度并将其插入数据库。为每个操作分别创建功能。

无法使用Python在表中插入或在MySQL中创建表

2 个答案: