# -*- coding: UTF- 8  -*-
import pyodbc

SCHEMAS = ('NSI','NSITEMP','NSICTRL',)

cur = pyodbc.connect('DSN=nsiii').cursor()
cur.execute('''
    select rtrim(TABSCHEMA), TABNAME, COLNAME, TYPENAME, LENGTH
    from SYSCAT.COLUMNS
    where TABSCHEMA in (%s) and TYPENAME in ('CHARACTER','VARCHAR')''' %
    ','.join("'%s'"% sch for sch in SCHEMAS)  )

for TABSCHEMA, TABNAME, COLNAME, TYPENAME, LENGTH in cur.fetchall():
    print('ALTER TABLE %s.%s ALTER COLUMN %s SET DATA TYPE %s(%d);' %
          (TABSCHEMA, TABNAME, COLNAME, TYPENAME, LENGTH* 2 )            )