The first argument to execute must be a string or unicode query

Question

I am trying to upload a blob data to ms-sql db, using pyodbc. And I get "the first argument to execute must be a string or unicode query" error.

The code is

file = pyodbc.Binary(open("some_pdf_file.pdf", "r").read())

cur.execute("INSERT INTO BlobDataForPDF(ObjectID, FileData, Extension) VALUES ('1', " + file + ", '.PDF')")
cur.commit()

The first argument, ObjectID, is sent as a string. I don't see any problem but am I missing something?

Answer 1

Use parameterized insert:

file = pyodbc.Binary(open("some_pdf_file.pdf", "r").read())
sql = "insert into BlobDataForPDF(ObjectID, FileData, Extension) values (?, ?, ?)"
cur.execute(sql, ('1', file, '.PDF'))
cur.commit()

The current code is attempting to concatenate binary data with your insert string. Using parameters isolates your SQL string from the inserted values, protecting against SQL injection and is more efficient if you execute the insert multiple times with different values. Sample usage here.