How can I get name of table by datatable row object

Anvil Q&A
1

Hi there,

Is there any way to get table name from datatable row object. Something like this

def function_a(datatable_row):
return (tablename(datatable_row))

Thank you,

2

Hi @mussa.butt,

There’s no built-in way to get the table name from the Row object.

Are you able to provide a bit more context about what you’re doing? I’d have thought that usually if you’ve retrieved a Data Table row, you know what table it came from, but of course I haven’t thought of all possible use-cases!

If you can narrow it down to a finite list of tables you could try something like this:

def table_of_row(row):
  for table in [app_tables.table1, app_tables.table2]:
    if table.has_row(row):
      return table

  raise Exception("Row was not in list of tables.")

That still runs a lookup for the row in each table, which may require round-trips to the database, depending on caching. A better solution would be to check that the candidate Row has the correct columns - assuming you don’t have two tables with identical schemas:

def table_of_row_faster(row):
  for table in [app_tables.table1, app_tables.table2]:
    columns = [c['name'] for c in table.list_columns()]
    
    for column in columns:
      try:
        row[column]
      except IndexError:
        # This column was not in the row, so it's not from this table
        break
    else:
      # We didn't break out of the loop, so this must be the correct table
      return table
    
    raise Exception("Row was not in list of tables.")

Here’s an app that demonstrates that

https://anvil.works/build#clone:EIRJ6TILVXXVIZVE=7XFABDB7H7HEDCXCVXJ6DUM3