Python cx_Oracle merge mystery - working in SQL Dev not working in python33

Question

I am using python33 and cx_oracle (with Oracle 11g) to analyze a database, but I have run into a problem. The problem is with this SQL: merge into ftab01 a using (select username , count (case when action ='friend' then 1 end) friendCount from pool_1 group by username) b on (a.USERNAME=b.username) WHEN MATCHED THEN update set a.friendCount=b.friendCount if I run this command in SQL Developer, everything works perfectly, but if I do this: cursor.execute("merge into ftab01 a using (select username , count (case when action ='friend' then 1 end) friendCount from pool_1 group by username) b on (a.USERNAME=b.username) WHEN MATCHED THEN update set a.friendCount=b.friendCount"), it will fail (without any error! - It just does not change the table). Other commands are working properly (for example: cursor.execute('alter table '+self.tabname + ' add ('+column_name+' number)') - this code is just two lines above the problematic code. I have no idea what might be wrong, I tried googling for longer time but I haven't found anything (maybe because I don't know how to name this problem)

Code where I used it:

def action_counts(self,action_list):
sql = "merge into "+self.tabname + " a using (select username "
sql_when_matched ="";
for action in action_list:
  column_name = (action+'Count').replace('-','_')
  print(column_name)
  sql += ", count (case when action ='"+action+"' then 1 end) "+column_name
  sql_when_matched += " a."+column_name+"=b."+column_name+", "
  cursor.execute('alter table '+self.tabname + ' add ('+column_name+' number)')
sql += " from pool_1 group by username) b on (a.USERNAME=b.username) WHEN MATCHED THEN update set "+sql_when_matched
sq2 = sql.rstrip().rstrip(",")
print(sq2)
cursor.execute(sq2)

#this is the printed sq2 and copy-pasted into execute() (and if copy-pasted to SQL Developer it is working properly)
cursor.execute("merge into ftab01 a using (select username , count (case when action ='friend' then 1 end) friendCount from pool_1 group by username) b on (a.USERNAME=b.username) WHEN MATCHED THEN update set  a.friendCount=b.friendCount")

Since it does not produce any error message I have no idea what could be wrong, any help is appreciated.

Answer 1

Are you commiting the update? Depending on your version of Oracle the your alter table may be autocommitted but the merge may be rolled back.

try adding:

Connection.commit()

after the merge and see if it works.

Answer 2

As I understand, you are executing SQL in PYTHON that have MERGE statement. It required commit. For this kindly enable Auto commit after connection.

connconnection = connection.execution_options(autocommit=True)