python - Warning: Data truncated for column 'src_address' at row 1 -

from pox.core import core import pox.openflow.libopenflow_01 of import re  import datetime import time sqlalchemy import create_engine, foreignkey sqlalchemy import column, date, integer, string sqlalchemy.ext.declarative import declarative_base sqlalchemy.orm import relationship, backref sqlalchemy import create_engine sqlalchemy.orm import sessionmaker sqlalchemy.sql.expression import exists log = core.getlogger()  engine = create_engine('mysql://root@192.168.129.139/nwtopology', echo=false) base = declarative_base() session = sessionmaker(bind=engine) session = session()  class sourcetoport(base):     """"""     __tablename__ = 'source_to_port'     id = column(integer, primary_key=true)     port_no        = column(integer)     src_address    = column(string(16),index=true)      #-----------------------------------------     def __init__(self, src_address,port_no):         """"""         self.src_address = src_address         self.port_no     = port_no     #create tables    base.metadata.create_all(engine)      def act_like_switch (self, packet, packet_in):   """ implement switch-like behavior. """ # learn port source mac #print "recieved port ",packet_in.in_port , "source ",packet.src ,"dest" , packet.dst self.mac_to_port[packet.src]=packet_in.in_port r_res = session.query(sourcetoport).filter_by(src_address=str(packet.src)).first() if r_res none:     print "inserting entry"     start = time.time()     entry = sourcetoport(src_address=str(packet.src) , port_no=packet_in.in_port)     #add record session object     session.add(entry)     #add record session object     session.commit()     end = time.time()     elapsed = end - start     print "elapsed insert time ",elapsed else:     print "entry present" 

i have network sending packets 1 host another.the expected behaviour first time src_address,port pair should inserted sql database , thereafter should retrieve operation.i have tested functionlity working correctly local database using sqlite.then shifted remote database using mysql.

now find

if r_res none: 

is true,meaning

r_res = session.query(sourcetoport).filter_by(src_address=str(packet.src)).first()

is failing.

i suspect has wrong query / add mysql different sqlite.

it did print out warning below when inserting entry. /usr/lib/python2.7/dist-packages/sqlalchemy/engine/default.py:330: warning: data truncated column 'src_address' @ row 1   cursor.execute(statement, parameters) 

i can't figure out seems problem.

based on comments have printed out size of src_address trying insert.

 print 'length of src addreess',len(str(packet.src))  prints 17 

and have increased size of src_address 17,32 , 64.still same error

the following approach might save time in future.

there 1 more way of updating columns without recreating table - using alter table query.

alter table source_to_port modify src_address varchar(32); 

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