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<h1>Specifications of QDBM for Perl</h1>

<div class="note">Copyright (C) 2000-2006 Mikio Hirabayashi</div>
<div class="note">Last Update: Thu, 26 Oct 2006 15:00:20 +0900</div>
<div class="navi">[<a href="plapidoc/index.html">API</a>] [<a href="plspex-ja.html" hreflang="ja">Japanese</a>]</div>

<hr />

<h2>Table of Contents</h2>

<ol>
<li><a href="#overview">Overview</a></li>
<li><a href="#installation">Installation</a></li>
<li><a href="#examples">Examples</a></li>
<li><a href="#bugs">Bugs</a></li>
</ol>

<hr />

<h2><a name="overview" id="overview" class="head">Overview</a></h2>

<p>QDBM provides API for Perl.  This encapsulates the basic API, the extended API and the advanced API of QDBM.  These APIs are implemented with the APIs for C called with XS language.  There are two kinds of interfaces to handle a database: using methods directly and using tying functions with a hash.</p>

<p>In case of using methods, you call the constructor `new' of the class `Depot', `Curia' or `Villa' to open a database file or directory and get the handle.  The method `close' is used in order to close the database.  If the instance is destroyed without closing the database explicitly, the destructor closes the database.  The method `put' is used in order to store a record.  The method `out' is used in order to delete a record.  The method `get' is used in order to retrieve a record.  Besides, most operations like ones of the APIs for C are available.</p>

<p>In case of using tying functions, you call the `tie' function whose parameters are the same as ones of the constructor.  After tying, operations with the tied hash perform as operations to the binded database.  You use the `untie' function to close the database.</p>

<p>Although keys and values of storing records are treated as strings, binary data can be stored as they are.  `Depot' realizes a hash database with a file.  `Curia' realizes a hash database with a directory and multiple files.  `Villa' realizes a B+ tree database with a file.  `Depot' is fastest.  `Curia' is most scalable.  `Villa' provides cursor supporting ordering access.</p>

<p>For more information about the APIs, read documents in the sub directory `<a href="plapidoc/">plapidoc</a>'.</p>

<hr />

<h2><a name="installation" id="installation" class="head">Installation</a></h2>

<p>Make sure that Perl 5.6.0 or later version is installed and make sure that QDBM is installed under `/usr/local'.</p>

<p>Change the current working directory to the sub directory named `perl'.</p>

<pre>cd perl
</pre>

<p>Run the configuration script.</p>

<pre>./configure
</pre>

<p>Build programs.</p>

<pre>make
</pre>

<p>Perform self-diagnostic test.</p>

<pre>make check
</pre>

<p>Install programs.  This operation must be carried out by the root user.</p>

<pre>make install
</pre>

<p>When a series of work finishes, `Depot.so', `Depot.pm', `Curia.so', `Curia.pm', `Villa.so', `Villa.pm', and so on are installed under an appropriate directory according to the install directory of Perl.  Executable commands `pldptest', `plcrtest', and `plvltest' will be installed in `/usr/local/bin'.</p>

<p>To uninstall them, execute the following command after `./configure'.  This operation must be carried out by the root user.</p>

<pre>make uninstall
</pre>

<hr />

<h2><a name="examples" id="examples" class="head">Examples</a></h2>

<p>The following example stores and retrieves a phone number, using the name as the key.</p>

<pre>use Depot;

use constant NAME =&gt; "mikio";
use constant NUMBER =&gt; "000-1234-5678";
use constant DBNAME =&gt; "book";

sub main {
    my($depot, $val);

    # open the database
    if(!($depot = new Depot(&amp;DBNAME, Depot::OWRITER | Depot::OCREAT))){
        printf(STDERR "new failed: %s\n", $Depot::errmsg);
        return 1;
    }

    # store the record
    if(!$depot-&gt;put(&amp;NAME, &amp;NUMBER)){
        printf(STDERR "put failed: %s\n", $Depot::errmsg);
    }

    # retrieve the record
    if(!($val = $depot-&gt;get(&amp;NAME))){
        printf(STDERR "get failed: %s\n", $Depot::errmsg);
    } else {
        printf("Name: %s\n", &amp;NAME);
        printf("Number: %s\n", $val);
    }

    # close the database
    if(!$depot-&gt;close()){
        printf(STDERR "close failed: %s\n", $Depot::errmsg);
        return 1;
    }

    return 0;
}

exit(main());
</pre>

<p>The following example is a transcription of the one above, using tying functions.</p>

<pre>use Depot;

use constant NAME =&gt; "mikio";
use constant NUMBER =&gt; "000-1234-5678";
use constant DBNAME =&gt; "book";

sub main {
    my(%hash, $val);

    # open the database
    if(!tie(%hash, "Depot", &amp;DBNAME, Depot::OWRITER | Depot::OCREAT)){
        printf(STDERR "tie failed: %s\n", $Depot::errmsg);
        return 1;
    }

    # store the record
    if(!($hash{&amp;NAME} = &amp;NUMBER)){
        printf(STDERR "store failed: %s\n", $Depot::errmsg);
    }

    # retrieve the record
    if(!($val = $hash{&amp;NAME})){
        printf(STDERR "fetch failed: %s\n", $Depot::errmsg);
    } else {
        printf("Name: %s\n", &amp;NAME);
        printf("Number: %s\n", $val);
    }

    # close the record
    if(!untie(%hash)){
        printf(STDERR "untie failed: %s\n", $Depot::errmsg);
        return 1;
    }

    return 0;
}

exit(main());
</pre>

<p>The following example performs forward matching search for strings, using the class `Villa'.</p>

<pre>use Villa;

use constant DBNAME =&gt; "words";
use constant PREFIX =&gt; "apple";

sub main {
    my($villa, $key, $val);

    # open the database
    if(!($villa = new Villa(&amp;DBNAME, Villa::OWRITER | Villa::OCREAT))){
        printf(STDERR "new failed: %s\n", $Villa::errmsg);
        return 1;
    }

    # store the record
    if(!$villa-&gt;put("applet", "little application", Villa::DDUP) ||
       !$villa-&gt;put("aurora", "polar wonderwork", Villa::DDUP) ||
       !$villa-&gt;put("apple", "delicious fruit", Villa::DDUP) ||
       !$villa-&gt;put("amigo", "good friend", Villa::DDUP) ||
       !$villa-&gt;put("apple", "big city", Villa::DDUP)){
        printf(STDERR "put failed: %s\n", $Villa::errmsg);
    }

    # set the cursor at the top of candidates
    $villa-&gt;curjump(&amp;PREFIX);

    # scan with the cursor
    while($key = $villa-&gt;curkey()){
        my($prefix) = &amp;PREFIX;
        ($key =~ m/^$prefix/) || last;
        $val = $villa-&gt;curval();
        printf("%s: %s\n", $key, $val);
        $villa-&gt;curnext();
    }

    # close the database
    if(!$villa-&gt;close()){
        printf(STDERR "close failed: %s\n", $Villa::errmsg);
        return 1;
    }

    return 0;
}

exit(main());
</pre>

<hr />

<h2><a name="bugs" id="bugs" class="head">Bugs</a></h2>

<p>So far, this API is not associated with AnyDBM_File.</p>

<p>This API can be implemented more effectively by Perl hackers.</p>

<p>For the sake of simplicity of interface, Curia for Perl does not feature handling large objects, and Villa for Perl can not be binded with a comparing function defined by users.</p>

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