Updating tables within cursor loop
To demonstrate how to use a cursor to update records we'll create a running total of the number of Oscars our films have won.To begin with we'll declare a couple of variables and set their default values.think of this as a "join_field" join_table -- table with fields to add to source_table join_key -- field to match values of the "in_field" join_values -- fields to add to source_table (list) """ def Message(msg): print msg arcpy.Add Message(msg) # Get Catalog path (for feature layers and table views) cat_path = arcpy.In the example below, I'm trying to update the field Current POs in temporary table #t1, based upon a query that uses to reference this, but it doesn't work. Address Type = '1801') - (select sum() from Purchase Order Line POL inner join Supplier Address SA ON POL. Supplier_ID inner join Purchase Order Header POH ON POH. I have also attempted to use an update statement against cur PO, also unsuccessfully.
 I have a table, say, xx_my_big_table_t which could potentially have 100,000 rows.
So far in this series we've been concerned with simply reading data from tables using a cursor.
In this final part we'll look at how you can use a cursor to modify data as well.
The easiest way to declare a cursor that can be used to update records is to simply use the default cursor type: Using the code above will declare a cursor which can used to update records.
You can make things a little more obvious by explicitly stating that the cursor is to be used for updating, as shown below: This cursor can be used to update any field from the underlying data set.