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Python / postgres / psycopg2：获取刚刚插入的行的ID

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问题：Python / postgres / psycopg2：获取刚刚插入的行的ID
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回答 1
回答 2

问题：Python / postgres / psycopg2：获取刚刚插入的行的ID

我正在使用Python和psycopg2连接到Postgres。

当我插入一行时…

sql_string = "INSERT INTO hundred (name,name_slug,status) VALUES ("
sql_string += hundred_name + ", '" + hundred_slug + "', " + status + ");"
cursor.execute(sql_string)

…如何获取刚插入的行的ID？试：

hundred = cursor.fetchall()

使用时返回错误RETURNING id：

sql_string = "INSERT INTO domes_hundred (name,name_slug,status) VALUES ("
sql_string += hundred_name + ", '" + hundred_slug + "', " + status + ") RETURNING id;"
hundred = cursor.execute(sql_string)

简单地返回None。

更新：也是currval（即使直接在postgres中使用此命令也可以）：

sql_string = "SELECT currval(pg_get_serial_sequence('hundred', 'id'));"
hundred_id = cursor.execute(sql_string)

有人可以建议吗？

谢谢！

点击查看英文原文

I’m using Python and psycopg2 to interface to postgres.

When I insert a row…

sql_string = "INSERT INTO hundred (name,name_slug,status) VALUES ("
sql_string += hundred_name + ", '" + hundred_slug + "', " + status + ");"
cursor.execute(sql_string)

… how do I get the ID of the row I’ve just inserted? Trying:

hundred = cursor.fetchall()

returns an error, while using RETURNING id:

sql_string = "INSERT INTO domes_hundred (name,name_slug,status) VALUES ("
sql_string += hundred_name + ", '" + hundred_slug + "', " + status + ") RETURNING id;"
hundred = cursor.execute(sql_string)

simply returns None.

UPDATE: So does currval (even though using this command directly into postgres works): 

sql_string = "SELECT currval(pg_get_serial_sequence('hundred', 'id'));"
hundred_id = cursor.execute(sql_string)

Can anyone advise?

thanks!

回答 0

cursor.execute("INSERT INTO .... RETURNING id")
id_of_new_row = cursor.fetchone()[0]

并且，请不要手动构建包含值的SQL字符串。您可以（并且应该！）分别传递值，从而不必进行转义和SQL注入：

sql_string = "INSERT INTO domes_hundred (name,name_slug,status) VALUES (%s,%s,%s) RETURNING id;"
cursor.execute(sql_string, (hundred_name, hundred_slug, status))
hundred = cursor.fetchone()[0]

有关更多详细信息，请参见psycopg文档：http ://initd.org/psycopg/docs/usage.html#passing-parameters-to-sql-queries

点击查看英文原文 
cursor.execute("INSERT INTO .... RETURNING id")
id_of_new_row = cursor.fetchone()[0]

And please do not build SQL strings containing values manually. You can (and should!) pass values separately, making it unnecessary to escape and SQL injection impossible:

sql_string = "INSERT INTO domes_hundred (name,name_slug,status) VALUES (%s,%s,%s) RETURNING id;"
cursor.execute(sql_string, (hundred_name, hundred_slug, status))
hundred = cursor.fetchone()[0]

See the psycopg docs for more details: http://initd.org/psycopg/docs/usage.html#passing-parameters-to-sql-queries

回答 1

我到这里结束是因为我有一个类似的问题，但是我们使用的是Postgres-XC，它尚不支持RETURNING ID子句。在这种情况下，您可以使用：

cursor.execute（'INSERT INTO ........'）
cursor.execute（'SELECT LASTVAL（）'）
lastid = cursor.fetchone（）['lastval']

以防万一对任何人都有用！

点击查看英文原文

I ended up here because I had a similar problem, but we’re using Postgres-XC, which doesn’t yet support the RETURNING ID clause. In that case you can use:

cursor.execute('INSERT INTO ........')
cursor.execute('SELECT LASTVAL()')
lastid = cursor.fetchone()['lastval']

Just in case it was useful for anyone!

回答 2

考虑一个RETURNING子句http://www.postgresql.org/docs/8.3/static/sql-insert.html

点击查看英文原文

Consider a RETURNING clause http://www.postgresql.org/docs/8.3/static/sql-insert.html