PATH:
usr
/
share
/
doc
/
python-docs-2.7.5
/
html
/
library
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>11.8. dbm — Simple “database” interface — Python 2.7.5 documentation</title> <link rel="stylesheet" href="../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '2.7.5', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 2.7.5 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="top" title="Python 2.7.5 documentation" href="../index.html" /> <link rel="up" title="11. Data Persistence" href="persistence.html" /> <link rel="next" title="11.9. gdbm — GNU’s reinterpretation of dbm" href="gdbm.html" /> <link rel="prev" title="11.7. whichdb — Guess which DBM module created a database" href="whichdb.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head> <body> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="gdbm.html" title="11.9. gdbm — GNU’s reinterpretation of dbm" accesskey="N">next</a> |</li> <li class="right" > <a href="whichdb.html" title="11.7. whichdb — Guess which DBM module created a database" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >The Python Standard Library</a> »</li> <li><a href="persistence.html" accesskey="U">11. Data Persistence</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="module-dbm"> <span id="dbm-simple-database-interface"></span><h1>11.8. <a class="reference internal" href="#module-dbm" title="dbm: The standard "database" interface, based on ndbm. (Unix)"><tt class="xref py py-mod docutils literal"><span class="pre">dbm</span></tt></a> — Simple “database” interface<a class="headerlink" href="#module-dbm" title="Permalink to this headline">¶</a></h1> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">The <a class="reference internal" href="#module-dbm" title="dbm: The standard "database" interface, based on ndbm. (Unix)"><tt class="xref py py-mod docutils literal"><span class="pre">dbm</span></tt></a> module has been renamed to <tt class="xref py py-mod docutils literal"><span class="pre">dbm.ndbm</span></tt> in Python 3. The <a class="reference internal" href="../glossary.html#term-to3"><em class="xref std std-term">2to3</em></a> tool will automatically adapt imports when converting your sources to Python 3.</p> </div> <p>The <a class="reference internal" href="#module-dbm" title="dbm: The standard "database" interface, based on ndbm. (Unix)"><tt class="xref py py-mod docutils literal"><span class="pre">dbm</span></tt></a> module provides an interface to the Unix “(n)dbm” library. Dbm objects behave like mappings (dictionaries), except that keys and values are always strings. Printing a dbm object doesn’t print the keys and values, and the <tt class="xref py py-meth docutils literal"><span class="pre">items()</span></tt> and <tt class="xref py py-meth docutils literal"><span class="pre">values()</span></tt> methods are not supported.</p> <p>This module can be used with the “classic” ndbm interface, the BSD DB compatibility interface, or the GNU GDBM compatibility interface. On Unix, the <strong class="program">configure</strong> script will attempt to locate the appropriate header file to simplify building this module.</p> <p>The module defines the following:</p> <dl class="exception"> <dt id="dbm.error"> <em class="property">exception </em><tt class="descclassname">dbm.</tt><tt class="descname">error</tt><a class="headerlink" href="#dbm.error" title="Permalink to this definition">¶</a></dt> <dd><p>Raised on dbm-specific errors, such as I/O errors. <a class="reference internal" href="exceptions.html#exceptions.KeyError" title="exceptions.KeyError"><tt class="xref py py-exc docutils literal"><span class="pre">KeyError</span></tt></a> is raised for general mapping errors like specifying an incorrect key.</p> </dd></dl> <dl class="data"> <dt id="dbm.library"> <tt class="descclassname">dbm.</tt><tt class="descname">library</tt><a class="headerlink" href="#dbm.library" title="Permalink to this definition">¶</a></dt> <dd><p>Name of the <tt class="docutils literal"><span class="pre">ndbm</span></tt> implementation library used.</p> </dd></dl> <dl class="function"> <dt id="dbm.open"> <tt class="descclassname">dbm.</tt><tt class="descname">open</tt><big>(</big><em>filename</em><span class="optional">[</span>, <em>flag</em><span class="optional">[</span>, <em>mode</em><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#dbm.open" title="Permalink to this definition">¶</a></dt> <dd><p>Open a dbm database and return a dbm object. The <em>filename</em> argument is the name of the database file (without the <tt class="file docutils literal"><span class="pre">.dir</span></tt> or <tt class="file docutils literal"><span class="pre">.pag</span></tt> extensions; note that the BSD DB implementation of the interface will append the extension <tt class="file docutils literal"><span class="pre">.db</span></tt> and only create one file).</p> <p>The optional <em>flag</em> argument must be one of these values:</p> <table border="1" class="docutils"> <colgroup> <col width="17%" /> <col width="83%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Value</th> <th class="head">Meaning</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><tt class="docutils literal"><span class="pre">'r'</span></tt></td> <td>Open existing database for reading only (default)</td> </tr> <tr class="row-odd"><td><tt class="docutils literal"><span class="pre">'w'</span></tt></td> <td>Open existing database for reading and writing</td> </tr> <tr class="row-even"><td><tt class="docutils literal"><span class="pre">'c'</span></tt></td> <td>Open database for reading and writing, creating it if it doesn’t exist</td> </tr> <tr class="row-odd"><td><tt class="docutils literal"><span class="pre">'n'</span></tt></td> <td>Always create a new, empty database, open for reading and writing</td> </tr> </tbody> </table> <p>The optional <em>mode</em> argument is the Unix mode of the file, used only when the database has to be created. It defaults to octal <tt class="docutils literal"><span class="pre">0666</span></tt> (and will be modified by the prevailing umask).</p> </dd></dl> <div class="admonition-see-also admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt>Module <a class="reference internal" href="anydbm.html#module-anydbm" title="anydbm: Generic interface to DBM-style database modules."><tt class="xref py py-mod docutils literal"><span class="pre">anydbm</span></tt></a></dt> <dd>Generic interface to <tt class="docutils literal"><span class="pre">dbm</span></tt>-style databases.</dd> <dt>Module <a class="reference internal" href="gdbm.html#module-gdbm" title="gdbm: GNU's reinterpretation of dbm. (Unix)"><tt class="xref py py-mod docutils literal"><span class="pre">gdbm</span></tt></a></dt> <dd>Similar interface to the GNU GDBM library.</dd> <dt>Module <a class="reference internal" href="whichdb.html#module-whichdb" title="whichdb: Guess which DBM-style module created a given database."><tt class="xref py py-mod docutils literal"><span class="pre">whichdb</span></tt></a></dt> <dd>Utility module used to determine the type of an existing database.</dd> </dl> </div> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="whichdb.html" title="previous chapter">11.7. <tt class="docutils literal"><span class="pre">whichdb</span></tt> — Guess which DBM module created a database</a></p> <h4>Next topic</h4> <p class="topless"><a href="gdbm.html" title="next chapter">11.9. <tt class="docutils literal"><span class="pre">gdbm</span></tt> — GNU’s reinterpretation of dbm</a></p> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li><a href="../_sources/library/dbm.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../search.html" method="get"> <input type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="gdbm.html" title="11.9. gdbm — GNU’s reinterpretation of dbm" >next</a> |</li> <li class="right" > <a href="whichdb.html" title="11.7. whichdb — Guess which DBM module created a database" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >The Python Standard Library</a> »</li> <li><a href="persistence.html" >11. Data Persistence</a> »</li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 1990-2019, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="http://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Jul 03, 2019. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3. </div> </body> </html>
[+]
..
[-] cookie.html
[edit]
[-] email.html
[edit]
[-] rfc822.html
[edit]
[-] mac.html
[edit]
[-] xml.etree.elementtree.html
[edit]
[-] xml.sax.html
[edit]
[-] formatter.html
[edit]
[-] rexec.html
[edit]
[-] pprint.html
[edit]
[-] crypt.html
[edit]
[-] future_builtins.html
[edit]
[-] queue.html
[edit]
[-] ipc.html
[edit]
[-] ftplib.html
[edit]
[-] doctest.html
[edit]
[-] inspect.html
[edit]
[-] multifile.html
[edit]
[-] commands.html
[edit]
[-] tk.html
[edit]
[-] mimewriter.html
[edit]
[-] i18n.html
[edit]
[-] simplehttpserver.html
[edit]
[-] msilib.html
[edit]
[-] misc.html
[edit]
[-] codecs.html
[edit]
[-] compileall.html
[edit]
[-] cd.html
[edit]
[-] nntplib.html
[edit]
[-] itertools.html
[edit]
[-] textwrap.html
[edit]
[-] urllib.html
[edit]
[-] ctypes.html
[edit]
[-] site.html
[edit]
[-] imgfile.html
[edit]
[-] statvfs.html
[edit]
[-] math.html
[edit]
[-] __builtin__.html
[edit]
[-] code.html
[edit]
[-] fpectl.html
[edit]
[-] mmap.html
[edit]
[-] shelve.html
[edit]
[-] mhlib.html
[edit]
[-] bastion.html
[edit]
[-] readline.html
[edit]
[-] resource.html
[edit]
[-] functions.html
[edit]
[-] crypto.html
[edit]
[-] argparse.html
[edit]
[-] email.mime.html
[edit]
[-] imp.html
[edit]
[-] asyncore.html
[edit]
[-] sha.html
[edit]
[-] webbrowser.html
[edit]
[-] signal.html
[edit]
[-] grp.html
[edit]
[-] undoc.html
[edit]
[-] fractions.html
[edit]
[-] sunau.html
[edit]
[-] xmlrpclib.html
[edit]
[-] dis.html
[edit]
[-] audioop.html
[edit]
[-] termios.html
[edit]
[-] base64.html
[edit]
[-] fcntl.html
[edit]
[-] poplib.html
[edit]
[-] shlex.html
[edit]
[-] gc.html
[edit]
[-] tokenize.html
[edit]
[-] xml.sax.reader.html
[edit]
[-] types.html
[edit]
[-] modulefinder.html
[edit]
[-] locale.html
[edit]
[-] unix.html
[edit]
[-] fileinput.html
[edit]
[-] bdb.html
[edit]
[-] test.html
[edit]
[-] bsddb.html
[edit]
[-] anydbm.html
[edit]
[-] sun.html
[edit]
[-] email.header.html
[edit]
[-] zipimport.html
[edit]
[-] ossaudiodev.html
[edit]
[-] importlib.html
[edit]
[-] logging.handlers.html
[edit]
[-] email.generator.html
[edit]
[-] keyword.html
[edit]
[-] sched.html
[edit]
[-] zipfile.html
[edit]
[-] random.html
[edit]
[-] debug.html
[edit]
[-] aetypes.html
[edit]
[-] gl.html
[edit]
[-] marshal.html
[edit]
[-] mailcap.html
[edit]
[-] getopt.html
[edit]
[-] urllib2.html
[edit]
[-] codeop.html
[edit]
[-] fm.html
[edit]
[-] email.errors.html
[edit]
[-] atexit.html
[edit]
[-] stringio.html
[edit]
[-] python.html
[edit]
[-] threading.html
[edit]
[-] logging.config.html
[edit]
[-] gensuitemodule.html
[edit]
[-] email.encoders.html
[edit]
[-] fnmatch.html
[edit]
[-] intro.html
[edit]
[-] compiler.html
[edit]
[-] cmd.html
[edit]
[-] glob.html
[edit]
[-] ssl.html
[edit]
[-] pydoc.html
[edit]
[-] unittest.html
[edit]
[-] copy_reg.html
[edit]
[-] io.html
[edit]
[-] array.html
[edit]
[-] contextlib.html
[edit]
[-] colorpicker.html
[edit]
[-] numbers.html
[edit]
[-] autogil.html
[edit]
[-] docxmlrpcserver.html
[edit]
[-] aifc.html
[edit]
[-] simplexmlrpcserver.html
[edit]
[-] hotshot.html
[edit]
[-] modules.html
[edit]
[-] constants.html
[edit]
[-] py_compile.html
[edit]
[-] syslog.html
[edit]
[-] optparse.html
[edit]
[-] pwd.html
[edit]
[-] pdb.html
[edit]
[-] stringprep.html
[edit]
[-] user.html
[edit]
[-] numeric.html
[edit]
[-] index.html
[edit]
[-] __main__.html
[edit]
[-] new.html
[edit]
[-] bisect.html
[edit]
[-] mimetools.html
[edit]
[-] thread.html
[edit]
[-] internet.html
[edit]
[-] timeit.html
[edit]
[-] sysconfig.html
[edit]
[-] filesys.html
[edit]
[-] datatypes.html
[edit]
[-] popen2.html
[edit]
[-] tabnanny.html
[edit]
[-] 2to3.html
[edit]
[-] select.html
[edit]
[-] copy.html
[edit]
[-] hashlib.html
[edit]
[-] filecmp.html
[edit]
[-] uuid.html
[edit]
[-] email.parser.html
[edit]
[-] restricted.html
[edit]
[-] token.html
[edit]
[-] mm.html
[edit]
[-] nis.html
[edit]
[-] warnings.html
[edit]
[-] sgi.html
[edit]
[-] windows.html
[edit]
[-] runpy.html
[edit]
[-] symbol.html
[edit]
[-] idle.html
[edit]
[-] language.html
[edit]
[-] plistlib.html
[edit]
[-] tkinter.html
[edit]
[-] parser.html
[edit]
[-] uu.html
[edit]
[-] netrc.html
[edit]
[-] heapq.html
[edit]
[-] linecache.html
[edit]
[-] tty.html
[edit]
[-] macostools.html
[edit]
[-] dummy_threading.html
[edit]
[-] csv.html
[edit]
[-] macosa.html
[edit]
[-] whichdb.html
[edit]
[-] xml.dom.minidom.html
[edit]
[-] xml.sax.handler.html
[edit]
[-] sqlite3.html
[edit]
[-] wave.html
[edit]
[-] curses.panel.html
[edit]
[-] fileformats.html
[edit]
[-] urlparse.html
[edit]
[-] binascii.html
[edit]
[-] fl.html
[edit]
[-] frameworks.html
[edit]
[-] someos.html
[edit]
[-] macpath.html
[edit]
[-] sets.html
[edit]
[-] socket.html
[edit]
[-] mutex.html
[edit]
[-] xml.html
[edit]
[-] robotparser.html
[edit]
[-] mimetypes.html
[edit]
[-] posixfile.html
[edit]
[-] imputil.html
[edit]
[-] othergui.html
[edit]
[-] archiving.html
[edit]
[-] pyexpat.html
[edit]
[-] tix.html
[edit]
[-] repr.html
[edit]
[-] aepack.html
[edit]
[-] dbm.html
[edit]
[-] xml.dom.html
[edit]
[-] mailbox.html
[edit]
[-] pkgutil.html
[edit]
[-] htmllib.html
[edit]
[-] struct.html
[edit]
[-] exceptions.html
[edit]
[-] imghdr.html
[edit]
[-] curses.ascii.html
[edit]
[-] gdbm.html
[edit]
[-] gettext.html
[edit]
[-] hmac.html
[edit]
[-] imaplib.html
[edit]
[-] email.charset.html
[edit]
[-] email-examples.html
[edit]
[-] cgitb.html
[edit]
[-] cookielib.html
[edit]
[-] os.path.html
[edit]
[-] userdict.html
[edit]
[-] binhex.html
[edit]
[-] basehttpserver.html
[edit]
[-] colorsys.html
[edit]
[-] dummy_thread.html
[edit]
[-] jpeg.html
[edit]
[-] smtplib.html
[edit]
[-] turtle.html
[edit]
[-] re.html
[edit]
[-] dircache.html
[edit]
[-] functools.html
[edit]
[-] markup.html
[edit]
[-] spwd.html
[edit]
[-] sunaudio.html
[edit]
[-] platform.html
[edit]
[-] logging.html
[edit]
[-] smtpd.html
[edit]
[-] persistence.html
[edit]
[-] macos.html
[edit]
[-] telnetlib.html
[edit]
[-] sndhdr.html
[edit]
[-] json.html
[edit]
[-] pty.html
[edit]
[-] subprocess.html
[edit]
[-] profile.html
[edit]
[-] ic.html
[edit]
[-] dbhash.html
[edit]
[-] stdtypes.html
[edit]
[-] decimal.html
[edit]
[-] sys.html
[edit]
[-] cgi.html
[edit]
[-] wsgiref.html
[edit]
[-] winsound.html
[edit]
[-] quopri.html
[edit]
[-] os.html
[edit]
[-] xml.sax.utils.html
[edit]
[-] posix.html
[edit]
[-] string.html
[edit]
[-] datetime.html
[edit]
[-] tempfile.html
[edit]
[-] multiprocessing.html
[edit]
[-] msvcrt.html
[edit]
[-] rlcompleter.html
[edit]
[-] httplib.html
[edit]
[-] cmath.html
[edit]
[-] mimify.html
[edit]
[-] stat.html
[edit]
[-] sgmllib.html
[edit]
[-] development.html
[edit]
[-] cgihttpserver.html
[edit]
[-] email.message.html
[edit]
[-] gzip.html
[edit]
[-] getpass.html
[edit]
[-] imageop.html
[edit]
[-] symtable.html
[edit]
[-] time.html
[edit]
[-] netdata.html
[edit]
[-] zlib.html
[edit]
[-] collections.html
[edit]
[-] operator.html
[edit]
[-] easydialogs.html
[edit]
[-] _winreg.html
[edit]
[-] socketserver.html
[edit]
[-] weakref.html
[edit]
[-] tarfile.html
[edit]
[-] carbon.html
[edit]
[-] strings.html
[edit]
[-] distutils.html
[edit]
[-] difflib.html
[edit]
[-] email.util.html
[edit]
[-] shutil.html
[edit]
[-] pickletools.html
[edit]
[-] curses.html
[edit]
[-] ast.html
[edit]
[-] aetools.html
[edit]
[-] allos.html
[edit]
[-] pickle.html
[edit]
[-] calendar.html
[edit]
[-] configparser.html
[edit]
[-] chunk.html
[edit]
[-] email.iterators.html
[edit]
[-] trace.html
[edit]
[-] asynchat.html
[edit]
[-] __future__.html
[edit]
[-] pyclbr.html
[edit]
[-] al.html
[edit]
[-] dl.html
[edit]
[-] miniaeframe.html
[edit]
[-] abc.html
[edit]
[-] errno.html
[edit]
[-] xml.dom.pulldom.html
[edit]
[-] xdrlib.html
[edit]
[-] scrolledtext.html
[edit]
[-] framework.html
[edit]
[-] md5.html
[edit]
[-] unicodedata.html
[edit]
[-] ttk.html
[edit]
[-] fpformat.html
[edit]
[-] htmlparser.html
[edit]
[-] custominterp.html
[edit]
[-] dumbdbm.html
[edit]
[-] bz2.html
[edit]
[-] pipes.html
[edit]
[-] traceback.html
[edit]