python - Psycopg2:使用 with ... as 在 python 中进行查询

Question

使用 psycopg2 进行查询的最佳模式是什么？

这个:

# get_connection is a function that returns a connection to the db.
with get_connection() as conn:
    with conn.cursor() as cursor:
        cursor.execute("SELECT * FROM test_table")

or simply this:

with get_connection() as conn:
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM test_table")

Answer 1

从 2.5 版开始，您现在可以将 with 用于 psycopg2 连接和游标。文档是 here .

它提到:

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.

因此，我认为您上面使用嵌套 with block 的第一个代码片段是更好的模式。