python code to count rows of all tables in a sqlite database

sqlite_rowcount.py

# python 3
# what for: count rows of all tables in the main sqlite db
# caution: this overwrites the file test.csv


import sqlite3
import sys
import subprocess

dbfile='/tmp/test.db'
filetype=subprocess.check_output(["file", dbfile], encoding="utf-8")
if "SQLite" not in filetype.split(":")[1]:
  sys.exit('I am not convinced that {} is a valid sqlite database'.format(dbfile))

table_rowcount={}
try:
  conn = sqlite3.connect(dbfile)
  cursor = conn.cursor()
  cursor.execute("SELECT name FROM sqlite_master WHERE type='table';")
  tables = cursor.fetchall()
  for table in tables:
    cursor.execute("select count(*) from {}".format(table[0]))
    table_rowcount[table[0]]=cursor.fetchone()[0]
  with open('test.csv', 'w') as f:
    for key in table_rowcount.keys():
      f.write("%s,%s\n"%(key,table_rowcount[key]))
  cursor.close()
except sqlite3.Error as error:
  print("SQLite error: {}".format(error), file=sys.stderr)
except Exception as exc:
  print(exc, file=sys.stderr)
finally:
    if (conn):
        conn.close()