Python - MySQLdb: ValueError - unsupported format - although the use of the execute substitution

Question

I'm trying to UPDATE some BLOB images in a database with the python-mysqldb package but i always get this error:

ValueError: unsupported format character ',' (0x2c) at index 64

I've successfully added the images some time ago with the execute substitution tools for example like this:

Set up connection to db:

db  = MySQLdb.connect( host="127.0.0.1", port=0815, user="javert", passwd="ureyes", db="some_db") 
cur = db.cursor()

read image files:

images = [ open( image_file, 'rb') for image_file in folder ]
image1, ..., image6 = images

insert images:

command = """INSERT INTO database_table (column1, ..., column6) VALUES (%s,%s,%s,%s,%s,%s)"""
cur.execute( command, args=( image1, ..., image6))
db.commit()

Now I've replaced the insert command with the following and get the described error:

"""UPDATE database_table SET column1=%s, column2=%s, column3=%s, column4=s%, column5=%s, column6=%s WHERE id=table_row_id"""

Thank You for your help!

@SomethingSomething: I didn't know about this module. Could you describe the advantages of it compared to mysqldb? Why should i use it? — Christian Kaiser
– Christian Kaiser, Commented Dec 16, 2014 at 12:12
pyodbc is compatible with more libraries and does not need mysql dlls for its installation. I now noticed that mysql-python was updated more recently, so I don't know what's better — SomethingSomething
– SomethingSomething, Commented Dec 16, 2014 at 13:03

Thomas Orozco · Accepted Answer · 2014-12-16 11:11:02Z

2

column4=s%, should be column4=%s, (note the inverted , and s).

Observe that this is what the error message says (, isn't an appropriate "format character"): the "format character" is what comes after the %, and , is not a valid one.

answered Dec 16, 2014 at 11:11

Thomas Orozco

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3 Comments

Christian Kaiser Over a year ago

Problem solved. Now everything runs like charm. Thank you very much for your help and also for the description of the error. I promise i will check that first next time! '

Thomas Orozco Over a year ago

@ChristianKaiser Don't worry — I didn't mean to imply you should have known, you need to learn about that error one day before you can recognize it : )

Christian Kaiser Over a year ago

I resent because i should have take a look into it but i ways so busy trying to find a mysqldb related format problem because i took my some trial and error to get the execute logic work with blobs. So thanks again for pointing it out and have a nice Christmas with your family.

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