postgresql psycopg2“类型错误：并非所有参数都在字符串格式化期间转换”
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psycopg2 "TypeError: not all arguments converted during string formatting"
提问by Ian
I'm trying to insert binary data (a whirlpool hash) into a PG table and am getting an error:
我正在尝试将二进制数据（漩涡散列）插入 PG 表中，但出现错误：
TypeError: not all arguments converted during string formatting
code:
代码：
cur.execute("""
INSERT INTO
sessions
(identity_hash, posted_on)
VALUES
(%s, NOW())
""", identity_hash)
I tried adding conn.Binary("identity_hash") to the variable before insertion, but get the same error.
我尝试在插入之前将 conn.Binary("identity_hash") 添加到变量中，但得到相同的错误。
The identity_hash column is a bytea.
identity_hash 列是一个字节。
Any ideas?
有任何想法吗？
采纳答案by Milen A. Radev
Have you taken a look at the "examples/binary.py" script in the psycopg2 source distribution? It works fine here. It looks a bit different than your excerpt:
您是否查看了 psycopg2 源代码分发中的“examples/binary.py”脚本？它在这里工作正常。它看起来与您的摘录有点不同：
data1 = {'id':1, 'name':'somehackers.jpg',
'img':psycopg2.Binary(open('somehackers.jpg').read())}
curs.execute("""INSERT INTO test_binary
VALUES (%(id)s, %(name)s, %(img)s)""", data1)
回答by piro
The problem you have is that you are passing the object as second parameter: the second parameters should be either a tuple or a dict. There is no shortcut as in the % string operator.
您遇到的问题是您将对象作为第二个参数传递：第二个参数应该是元组或字典。没有像 % 字符串运算符那样的快捷方式。
You should do:
你应该做：
cur.execute("""
INSERT INTO
sessions
(identity_hash, posted_on)
VALUES
(%s, NOW())
""", (identity_hash,))
回答by Salvador Dali
Encountered the same problem and found that this is actually covered in their FAQ
遇到了同样的问题，发现这个其实在他们的FAQ里有介绍
I try to execute a query but it fails with the error not all arguments converted during string formatting (or object does not support indexing). Why? Psycopg always require positional arguments to be passed as a sequence, even when the query takes a single parameter. And remember that to make a single item tuple in Python you need a comma! See Passing parameters to SQL queries.
我尝试执行一个查询，但它失败了，错误不是所有在字符串格式化期间转换的参数（或对象不支持索引）。为什么？Psycopg 始终要求将位置参数作为序列传递，即使查询采用单个参数也是如此。请记住，要在 Python 中创建单项元组，您需要一个逗号！请参阅将参数传递给 SQL 查询。
cur.execute("INSERT INTO foo VALUES (%s)", "bar") # WRONG
cur.execute("INSERT INTO foo VALUES (%s)", ("bar")) # WRONG
cur.execute("INSERT INTO foo VALUES (%s)", ("bar",)) # correct
cur.execute("INSERT INTO foo VALUES (%s)", ["bar"]) # correct
