python - 使用 pyodbc 将 pickle 对象插入数据库

Question

我尝试了以下方法，但没有成功:

keypoints_database = pickle.load( open( "5958.p", "rb" ) )

sql = 'INSERT INTO tb_fpdata (Std_SymbolNo , FP_Descriptors) VALUES (5958 , ?)' , pyodbc.Binary(keypoints_database)

我收到以下错误:

如何将对象保存到数据库？

Answer 1

因此您有一个包含 pickled 对象的二进制文件。文件的十六进制转储如下所示:

00000000: 8004 9515 0000 0000 0000 007d 9428 8c03  ...........}.(..
00000010: 666f 6f94 4b01 8c03 6261 7294 4b02 752e  foo.K...bar.K.u.

您可以将对象保存到二进制列，然后读回它并通过 pickle.loads 取消它，如下所示:

import pyodbc
import pickle

conn_str = (
    r'DRIVER=ODBC Driver 17 for SQL Server;'
    r'SERVER=.\SQLEXPRESS;'
    r'DATABASE=myDb;'
    r'Trusted_Connection=yes;'
)
cnxn = pyodbc.connect(conn_str, autocommit=True)
crsr = cnxn.cursor()
crsr.execute("CREATE TABLE #test (id INT PRIMARY KEY, pkl VARBINARY(max))")

# read pre-pickled object from file and save to table
with open(r'C:\Users\Gord\Desktop\data.pickle', 'rb') as f:
    sql = "INSERT INTO #test (id, pkl) VALUES (?, ?)"
    params = (1, f.read())
    crsr.execute(sql, params)

# read it back from database and unpickle it
pickled_data = crsr.execute("SELECT pkl FROM #test WHERE id=1").fetchval()
unpickled_object = pickle.loads(pickled_data)

print(unpickled_object)
# {'foo': 1, 'bar': 2}