6.2 Itse1359-1930-dbm and shelve databases

Table of contents

• Preface
• Questions
  • 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15
• Figure index
• Answers
• Miscellaneous

Preface

This module is one in a collection of modules on Python designed for teaching ITSE 1359 Introduction to Scripting Languages: Python at Austin Community College in Austin, TX.

This module contains review questions and answers keyed to material on the following web sites:

• The Python Standard Library - 12.5. dbm - Interfaces to Unix "databases"
• The Python Standard Library - 12.3. shelve - Python object persistence
• The Python Standard Library - 12.1. pickle - Python object serialization
• The Python Standard Library - 4.10. Mapping Types - dict

Once you study that module, you should be able to answer the review questions in this module.

The questions and the answers in this module are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back again.

(Note to blind and visually impaired students: with the exception of two bitmap images that are used solely as spacers to separate the questionsection from the answer section, all of the material in this module is presented in plain text format and should be accessible using an audio screen reader or abraille display. Note however that the required indentation may not be properly represented by an audio screen reader.)

Questions

Question 1

True or False? The webpage at The Python Standard Library - 12.1. pickle - Python object serialization contains the following warning:

Warning: The pickle module is not intended to be secure against erroneous or maliciously constructed data. Never unpickle data received from an untrusted or unauthenticated source.

Go to answer 1

Question 2

True or False? The webpage at The Python Standard Library - 12.3. shelve - Python object persistence contains the following warning:

Warning: Because the shelve module is backed by pickle, it is insecure to load a shelf from an untrusted source. Like with pickle, loading a shelf can execute arbitrary code.

Go to answer 2

Question 3

True or False? The webpage at The Python Standard Library - 12.5. dbm - Interfaces to Unix "databases" contains the following warning:

Warning: The dbm module is not intended to be secure against erroneous or maliciously constructed data. Neveruse dbm data received from an untrusted or unauthenticated source.

Go to answer 3

Question 4

True or False? dbm is a generic interface to variants of the DBM databases - dbm.gnu or dbm.ndbm . If neither of these modules is installed, the program will raise a "Module not found"error.

Go to answer 4

Question 5

True or False? The function named dbm.whichdb( filename ) can be called to determine which database module should be used to open a givendatabase file.

Go to answer 5

Question 6

True or False? The function named dbm.getDatabase can be called to open an existing dbm database file or to create a new dbm database file.

Go to answer 6

Question 7

True or False? The object returned by dbm.open supports the same basic functionality as tuples. Keys and their corresponding values can bestored, retrieved, and deleted. The in operator and the k eys method are available, as well as get and setdefault .