parameters: (self, table, column, type, not_null=None)
return_statement: return statements
docstring: get the statement for setting the column type
docstring_summary: get the statement for setting the column type
docstring_tokens: get the statement for setting the column type
function: def get_modify_column(self, table, column, type, not_null=None):
          ''' get the statement for setting the column type '''
          # this may not return the type exacty like before like varchar is in place of
          # varchar(256) due to the column type returned from the sql impl
          statements = []
          statements.append('ALTER TABLE "%s" ALTER COLUMN "%s" %s' \
              % (table,column,type))
          if not_null == None:
              return statements
          if not_null:
              # In order to set the column to disallow NULL values,
              # we must first set any current NULL values to the empty string ''.
              statements.append('UPDATE "%s" SET "%s"=\'\' WHERE %s IS NULL' \
              % (table,column, column))
  
              # Now that any existing NULL values for that column are set to the empty string,
              # proceed to alter the column so that it disallows NULL values.
              statements.append('ALTER TABLE "%s" ALTER COLUMN "%s" %s NOT NULL' \
              % (table,column,type))
          else:
              statements.append('ALTER TABLE "%s" ALTER COLUMN "%s" %s' \
                  % (table, column, type))
          return statements
function_tokens: def get_modify_column ( self , table , column , type , not_null = None ) : # this may not return the type exacty like before like varchar is in place of # varchar(256) due to the column type returned from the sql impl statements = [ ] statements . append ( 'ALTER TABLE "%s" ALTER COLUMN "%s" %s' % ( table , column , type ) ) if not_null == None : return statements if not_null : # In order to set the column to disallow NULL values, # we must first set any current NULL values to the empty string ''. statements . append ( 'UPDATE "%s" SET "%s"=\'\' WHERE %s IS NULL' % ( table , column , column ) ) # Now that any existing NULL values for that column are set to the empty string, # proceed to alter the column so that it disallows NULL values. statements . append ( 'ALTER TABLE "%s" ALTER COLUMN "%s" %s NOT NULL' % ( table , column , type ) ) else : statements . append ( 'ALTER TABLE "%s" ALTER COLUMN "%s" %s' % ( table , column , type ) ) return statements