python inserting and retrieving binary data into mysql

Question

I\'m using the MySQLdb package for interacting with MySQL. I\'m having trouble getting the proper type conversions.

I am using a 16-byte binary uuid as a primary key

Answer 1

One tip: you should be able to call uuid.uuid4().bytes to get the raw bytes. As for timestamps, if you want to perform time/date manipulation in SQL it's often easier to deal with real TIMESTAMP types.

I created a test table to try to reproduce what you're seeing:

CREATE TABLE xyz (
    added_id INT AUTO_INCREMENT NOT NULL,
    id BINARY(16) NOT NULL,
    PRIMARY KEY (added_id),
    UNIQUE (id)
) DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ENGINE=InnoDB;

My script is able to insert and query for the rows using the binary field as a key without problem. Perhaps you are incorrectly fetching / iterating over the results returned by the cursor?

import binascii
import MySQLdb
import uuid

conn = MySQLdb.connect(host='localhost')

key = uuid.uuid4()
print 'inserting', repr(key.bytes)
r = conn.cursor()
r.execute('INSERT INTO xyz (id) VALUES (%s)', key.bytes)
conn.commit()

print 'selecting', repr(key.bytes)
r.execute('SELECT added_id, id FROM xyz WHERE id = %s', key.bytes)
for row in r.fetchall():
    print row[0], binascii.b2a_hex(row[1])

Output:

% python qu.py    
inserting '\x96\xc5\xa4\xc3Z+L\xf0\x86\x1e\x05\xebt\xf7\\\xd5'
selecting '\x96\xc5\xa4\xc3Z+L\xf0\x86\x1e\x05\xebt\xf7\\\xd5'
1 96c5a4c35a2b4cf0861e05eb74f75cd5
% python qu.py
inserting '\xac\xc9,jn\xb2O@\xbb\xa27h\xcd