I have two functions (yes, they are ugly, I was getting ready to split them in to smaller bits when this particular hole in my skull opened up) in a module. They use the same list of dictionaries to create some tables in a gadfly database.
I know I could fix this in any number of ways (including, but not limited to, acting on the same input list twice, or acting on it in such a fashion in the first place), but I am trying to actually understand "self".
Here's the horrid, horrid mess:
class Create:
def freshDB(self, DBPATH, Fields):
self.Fields = Fields
for field in self.Fields.keys():
columns = self.Fields[field]
columns = columns.split(',')
query = ''
for each in columns:
query = "%s, %s varchar"%(query,each)
query = query[1:]
query = "Create Table %s (%s)"%(field,query)
self.Fields[field] = query
connection = gadfly.gadfly()
connection.startup("InventoryDB", DBPATH)
cursor = connection.cursor()
for field in self.Fields.keys():
cursor.execute(self.Fields[field])
connection.commit()
for field in self.Fields.keys():
cursor.execute("Select * from %s"%field)
print cursor.pp()
connection.close()
def comparisonTable(self, DBPATH, Fields, columns, mode):
query = ""
if mode == 'new':
connection = gadfly.gadfly("InventoryDB",DBPATH)
cursor = connection.cursor()
try:
cursor.execute("drop table comparison")
except:
print "No old table found."
columns = Fields["Common"].split(',')
for each in columns:
query = "%s, %s varchar"%(query,each)
query = query[1:]
query = "Create Table comparison (%s)"%query
cursor.execute(query)
connection.commit()
cursor.execute("select * from comparison")
print cursor.pp()
Now when I run freshDB from the other script:
Fields = {"Common":"Inventory_Number, Stock_Number, Location, Year, Make, Model, Part_Type, Mileage, Description, Interchange_Data, Condition, Price",
"EvilBay":"EvilBay_Title, EvilBay_Description",
"HappyBase":"HappyBase_Description, HappyBase_Long_Description"}
d = DBMod
d.Create().freshDB(DBPATH, Fields)
d.Create().comparisonTable(DBPATH, Fields, columns, "new")
the resulting query is:
Create Table comparison ( Inventory_Number varchar, Stock_Number varchar, Location varchar, Year varchar, Make varchar, Model varchar, Part_Type varchar, Mileage varchar, Description varchar, Interchange_Data varchar, Condition varchar, Price varchar)
The query from comparisonTable gives me:
Create Table comparison ( Create Table Common ( Inventory_Number varchar varchar, Stock_Number varchar varchar, Location varchar varchar, Year varchar varchar, Make varchar varchar, Model varchar varchar, Part_Type varchar varchar, Mileage varchar varchar, Description varchar varchar, Interchange_Data varchar varchar, Condition varchar varchar, Price varchar) varchar)
If I restate the "Fields" input list before running comparisonTable, my results are as expected (i.e. exactly like the first query, exept the table is named "comparison").
I thought that when "self" was invoked for a function then that data was acted on only for the scope of that function, yet the data is changed in the original. Why?
I'm sure this is so obvious that a crack-addled tapeworm head down in a bucket of stupid could understand it, unfortunately, I'm not quite at that level today. Sorry.
Thanks!
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