Question

What’s the best way to make psycopg2 pass parameterized queries to PostgreSQL? I don’t want to write my own escpaing mechanisms or adapters and the psycopg2 source code and examples are difficult to read in a web browser.

If I need to switch to something like PyGreSQL or another python pg adapter, that’s fine with me. I just want simple parameterization.

Answer 1

psycopg2 follows the rules for DB-API 2.0 (set down in PEP-249). That means you can call execute method from your cursor object and use the pyformat binding style, and it will do the escaping for you. For example, the following should be safe (and work):

cursor.execute("SELECT * FROM students WHERE last_name = %(lname)s", 
               {"lname": "Robert'); DROP TABLE students;--"})

Edit: tekHedd’s comment rightly points out that the SELECT and the DROP TABLE used different table names, so I fixed it.