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POCan BerkeleyDB in perl handle a hash of hashes of hashes (up to n)?
 

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  1. POCan BerkeleyDB in perl handle a hash of hashes of hashes (up to n)?
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    <p>I have a script that utilizes a hash, which contains four strings as keys whose values are hashes. These hashes also contain four strings as keys which also have hashes as their values. This pattern continues up to n-1 levels, which is determined at run-time. The nth-level of hashes contain integer (as opposed to the usual hash-reference) values. </p> <p>I installed the BerkeleyDB module for Perl so I can use disk space instead of RAM to store this hash. I assumed that I could simply tie the hash to a database, and it would work, so I added the following to my code: </p> <pre><code>my %tags = () ; my $file = "db_tags.db" ; unlink $file; tie %tags, "BerkeleyDB::Hash", -Filename =&gt; $file, -Flags =&gt; DB_CREATE or die "Cannot open $file\n" ; </code></pre> <p>However, I get the error:</p> <p>Can't use string ("HASH(0x1a69ad8)") as a HASH ref while "strict refs" in use at getUniqSubTreeBDB.pl line 31, line 1.</p> <p>To test, I created a new script, with the code (above) that tied to hash to a file. Then I added the following: </p> <pre><code>my $href = \%tags; $tags{'C'} = {} ; </code></pre> <p>And it ran fine. Then I added: </p> <pre><code>$tags{'C'}-&gt;{'G'} = {} ; </code></pre> <p>And it would give pretty much the same error. I am thinking that BerkeleyDB cannot handle the type of data structure I am creating. Maybe it was able to handle the first level (C->{}) in my test because it was just a regular key -> scaler? </p> <p>Anyways, any suggestions or affirmations of my hypothesis would be appreciated. </p>
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