Handling large ResultSets

Introduction to Databases in Python

Jason Myers

Co-Author of Essential SQLAlchemy and Software Engineer

Dealing with large ResultSets

fetchmany() lets us specify how many rows we want to act upon
We can loop over fetchmany()
It returns an empty list when there are no more records
We have to close the ResultProxy afterwards

Fetching many rows

while more_results:

    partial_results = results_proxy.fetchmany(50)

    if partial_results == []:
        more_results = False

    for row in partial_results:
        state_count[row.state] += 1

results_proxy.close()

Let's practice!

Introduction to Databases in Python