CODEWITHSUNDEEP
python-2.7daskdask-distributed
Uriel Vinetz
Uriel Vinetz

Reputation: 21

Dask read_sql_table error: 'instancemethod' object has no attribute '__getitem__'

I'm getting this error with this params:

import pandas as pd
import numpy as np
from sqlalchemy import create_engine
import dask.dataframe as dd
from sqlalchemy.sql import text
query = text( "Some SQL statement" )
df = dd.read_sql_table(table=query,uri='Some postgreSQL DB',index_col='id')

Yields this error:

/usr/local/lib/python2.7/dist-packages/dask/dataframe/io/sql.pyc in read_sql_table(table, uri, index_col, divisions, npartitions, limits, columns, bytes_per_chunk, **kwargs)
     73                          schema=schema)
     74 
---> 75     index = (table.columns[index_col] if isinstance(index_col, six.string_types)
     76              else index_col)
     77     if not isinstance(index_col, six.string_types + (elements.Label,)):

TypeError: 'instancemethod' object has no attribute '__getitem__'

Someone knows what's the issue?

Upvotes: 2

Views: 413

Answers (1)

mdurant
mdurant

Reputation: 28683

The table parameter must either be an existing table (and so be a string or a sa.Table instance) or a full sqlalchemy statement (e.g., sqlalchemy.sql.select()), in which you define the full set of columns to be fetched. The reason for this is, that we don't attempt to parse a generic query here, which may be backend-specific. You could leverage sqlalchemy yourself to transform your text query into a structured statement for this function.

Upvotes: 1

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