Python psycopg2 未能插入到postgresql表

Question

我正在使用以下命令尝试将记录插入到postgresql数据库表中，但它不起作用。我没有任何错误，但表中没有记录。我需要承诺什么的吗？我使用的是与Bitnami djangostack安装一起安装的postgresql数据库。

import psycopg2

try:
    conn = psycopg2.connect("dbname='djangostack' user='bitnami' host='localhost' password='password'")
except:
    print "Cannot connect to db"

cur = conn.cursor()

try:
    cur.execute("""insert into cnet values ('r', 's', 'e', 'c', 'w', 's', 'i', 'd', 't')""")
except:
    print "Cannot insert"

Answer 1

结果我最后需要conn.commit()

Answer 2

psycopg2与Python DB API兼容，因此自动提交功能在默认情况下处于关闭状态。您需要调用^{}将任何挂起的事务提交到数据库。由于连接（和游标）是上下文管理器，您只需使用with语句在离开上下文时自动提交/回滚事务：

with conn, conn.cursor() as cur:  # start a transaction and create a cursor
    cur.execute(sql)

从docs：

When a connection exits the with block, if no exception has been raised by the block, the transaction is committed. In case of exception the transaction is rolled back.

When a cursor exits the with block it is closed, releasing any resource eventually associated with it. The state of the transaction is not affected.

Answer 3

如果不想将每个条目提交到数据库，可以添加以下行：

conn.autocommit = True

所以你得到的代码是：

import psycopg2

try:
    conn = psycopg2.connect("dbname='djangostack' user='bitnami' host='localhost' password='password'")
    conn.autocommit = True
except:
    print "Cannot connect to db"

cur = conn.cursor()

try:
    cur.execute("""insert into cnet values ('r', 's', 'e', 'c', 'w', 's', 'i', 'd', 't')""")
except:
    print "Cannot insert"