Example: Executing SQL Statements and Handling Errors

In this example, you use the SQLError class of the sdb.sql module. To generate exceptions of this class, you create the following error situations: Execute a SELECT statement with an incorrect column name, and execute an SQL statement with an incorrect parameter.

Procedure

Create a Python script sample.py with the following contents:

Syntax Syntax

#
# Import Python modules
# ---------------------------------------------------
import sys
import sdb.sql
#
# Connect to the database
# ---------------------------------------------------
database_user = sys.argv [1]
database_user_password = sys.argv [2]
database_name = sys.argv [3]
session = sdb.sql.connect (database_user, database_user_password, database_name)
#
# Execute a SELECT statement with an incorrect column
# name unknown (error in the SQL statement)
#----------------------------------------------------
select = "SELECT unknown FROM hotel.customer"
try:
  cursor = session.sql (select)
except sdb.sql.SQLError, err:
  print "ERR [%d] %s" % (err.errorCode, err.message)
  print select
  print ("=" * (err.errorPos - 1)) + '^'
#
# Execute SQL statement with an incorrect parameter
# (error during execution of the SQL statement)
#-----------------------------------------------------
try:
  count = session.sqlX ("""INSERT INTO hotel.customer
  VALUES (?,?,?,?,?,?)""", ['wrong_data_type', 'Mrs', 'Jennifer', 'Parker', '10590', '0 N.Ash Street, #6'])
except sdb.sql.SQLError, err:
  print "ERR [%d] %s" % (err.errorCode, err.message)
#
# Close connection to the database
# ----------------------------------------------------
session.release ()

End of the code.

Call the Python script:
python sample_6.py MONA RED DEMODB

ERR [-4005] Unknown column name:UNKNOWN

SELECT unknown FROM hotel.customer

=======^

ERR [-817] Incompatible data types