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<h2 class="title" style="clear: both"><a id="db_load"></a>db_load</h2>
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<pre class="programlisting">db_load [-nTV] [-b blob_dir] [-c name=value] [-f file]
[-h home] [-P password] [-o blob_threshold]
[-t btree | hash | queue | recno] file
db_load [-r lsn | fileid] [-h home] [-P password] file </pre>
<p>
The <span class="command"><strong>db_load</strong></span> utility reads from the standard input and loads it into
the database <span class="bold"><strong>file</strong></span>. The database
<span class="bold"><strong>file</strong></span> is created if it does not
already exist.
</p>
<p>
The input to <span class="command"><strong>db_load</strong></span> must be in the output format specified by the
<a class="xref" href="db_dump.html" title="db_dump">db_dump</a> utility
or as specified by the <span class="bold"><strong>-T</strong></span>
option below.
</p>
<p>
The options are as follows:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<span class="bold"><strong>-b</strong></span>
</p>
<p>
Identifies the directory where BLOB data is stored. If
this option is not specified, then BLOB data is placed in a
subdirectory within the DB's environment. See also the
<span class="bold"><strong>-o</strong></span> option.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-c</strong></span>
</p>
<p>
Specify configuration options ignoring any value they may have based
on the input. The command-line format is <span class="bold"><strong>name=value</strong></span>. See the Supported Keywords section
below for a list of keywords supported by the <span class="bold"><strong>-c</strong></span> option.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-f</strong></span>
</p>
<p>
Read from the specified <span class="bold"><strong>input</strong></span> file
instead of from the standard input.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-h</strong></span>
</p>
<p>
Specify a home directory for the database environment.
</p>
<p>
If a home directory is specified, the database environment is opened
using the
<a class="link" href="envopen.html#envopen_DB_INIT_LOCK">DB_INIT_LOCK</a>,
<a class="link" href="envopen.html#envopen_DB_INIT_LOG">DB_INIT_LOG</a>,
<a class="link" href="envopen.html#envopen_DB_INIT_MPOOL">DB_INIT_MPOOL</a>,
<a class="link" href="envopen.html#envopen_DB_INIT_TXN">DB_INIT_TXN</a>, and
<a class="link" href="envopen.html#envopen_DB_USE_ENVIRON">DB_USE_ENVIRON</a>
flags to <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a>
(This means that <span class="command"><strong>db_load</strong></span> can be used to load data into databases while
they are in use by other processes.) If the
<a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> call fails, or if
no home directory is specified, the database is still updated, but the
environment is ignored; for example, no locking is done.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-n</strong></span>
</p>
<p>
Do not overwrite existing keys in the database when loading into an
already existing database. If a key/data pair cannot be loaded into
the database for this reason, a warning message is displayed on the
standard error output, and the key/data pair are skipped.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-o</strong></span>
</p>
<p>
Identifies the BLOB threshold in bytes. This threshold determines
when a data item will be stored as a BLOB. Data items sized
less than this threshold are stored as normal data within
the database. Data items larger than this size are stored
on-disk in a subdirectory set aside for the purpose.
Use the <span class="bold"><strong>-b</strong></span> command line
option to identify where BLOB data is stored.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-P</strong></span>
</p>
<p>
Specify an environment password. Although Berkeley DB utilities
overwrite password strings as soon as possible, be aware there may be
a window of vulnerability on systems where unprivileged users can see
command-line arguments or where utilities are not able to overwrite
the memory containing the command-line arguments.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-r</strong></span>
</p>
<p>
Reset the database's file ID or log sequence numbers (LSNs).
</p>
<p>
All database pages in transactional environments contain references to
the environment's log records. In order to copy a database into a
different database environment, database page references to the old
environment's log records must be reset, otherwise data corruption can
occur when the database is modified in the new environment. The
<span class="bold"><strong>-r</strong></span> <span class="bold"><strong>lsn</strong></span> option resets a database's log sequence
numbers.
</p>
<p>
All databases contain an ID string used to identify the database in
the database environment cache. If a database is copied, and used in
the same environment as another file with the same ID string,
corruption can occur. The <span class="bold"><strong>-r</strong></span>
<span class="bold"><strong>fileid</strong></span> option resets a database's
file ID to a new value.
</p>
<p>
<span class="bold"><strong>In both cases, the physical file specified by
the <span class="bold"><strong>file</strong></span> argument is modified
in-place.</strong></span>
</p>
</li>
<li>
<p>
<span class="bold"><strong>-T</strong></span>
</p>
<p>
The <span class="bold"><strong>-T</strong></span> option allows non-Berkeley DB
applications to easily load text files into databases.
</p>
<p>
If the database to be created is of type Btree or Hash, or the keyword
<span class="bold"><strong>keys</strong></span> is specified as set, the
input must be paired lines of text, where the first line of the pair is the
key item, and the second line of the pair is its corresponding data
item. If the database to be created is of type Queue or Recno and the
keyword <span class="bold"><strong>keys</strong></span> is not set, the input
must be lines of text, where each line is a new data item for the
database.
</p>
<p>
A simple escape mechanism, where newline and backslash (\) characters
are special, is applied to the text input. Newline characters are
interpreted as record separators. Backslash characters in the text
will be interpreted in one of two ways: If the backslash character
precedes another backslash character, the pair will be interpreted as
a literal backslash. If the backslash character precedes any other
character, the two characters following the backslash will be
interpreted as a hexadecimal specification of a single character; for
example, \0a is a newline character in the ASCII character set.
</p>
<p>
For this reason, any backslash or newline characters that naturally
occur in the text input must be escaped to avoid misinterpretation by
<span class="command"><strong>db_load</strong></span>.
</p>
<p>
If the <span class="bold"><strong>-T</strong></span> option is specified, the
underlying access method type must be specified using the <span class="bold"><strong>-t</strong></span> option.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-t</strong></span>
</p>
<p>
Specify the underlying access method. If no <span class="bold"><strong>-t</strong></span> option is specified, the database will be
loaded into a database of the same type as was dumped; for example, a
Hash database will be created if a Hash database was dumped.
</p>
<p>
Btree and Hash databases may be converted from one to the other.
Queue and Recno databases may be converted from one to the other. If
the <span class="bold"><strong>-k</strong></span> option was specified on the
call to <a class="xref" href="db_dump.html" title="db_dump">db_dump</a> then
Queue and Recno databases may be converted to Btree or Hash, with the
key being the integer record number.
</p>
</li>
<li>
<p>
<span class="bold"><strong>-V</strong></span>
</p>
<p>
Write the library version number to the standard output, and exit.
</p>
</li>
</ul>
</div>
<p>
The <span class="command"><strong>db_load</strong></span> utility may be used with a Berkeley DB
environment (as described for the <span class="bold"><strong>-h</strong></span>
option, the environment variable
<span class="bold"><strong>DB_HOME</strong></span>, or because the utility
was run in a directory containing a Berkeley DB environment).
In order to avoid environment corruption when using a
Berkeley DB environment, <span class="command"><strong>db_load</strong></span> should always be given the chance to
detach from the environment and exit gracefully. To cause <span class="command"><strong>db_load</strong></span> to
release all environment resources and exit cleanly, send it an
interrupt signal (SIGINT).
</p>
<p>
The <span class="command"><strong>db_load</strong></span> utility exits 0 on success, 1 if one or more key/data
pairs were not loaded into the database because the key already
existed, and >1 if an error occurs.
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp55152152"></a>Examples</h3>
</div>
</div>
</div>
<p>
The <span class="command"><strong>db_load</strong></span> utility can be used to load text files into databases. For
example, the following command loads the standard UNIX
<span class="emphasis"><em>/etc/passwd</em></span> file into a database, with the login
name as the key item and the entire password entry as the data item:
</p>
<pre class="programlisting"> awk -F: '{print $1; print $0}' < /etc/passwd |
sed 's/\\/\\\\/g' | db_load -T -t hash passwd.db </pre>
<p>
Note that backslash characters naturally occurring in the text are
escaped to avoid interpretation as escape characters by
<span class="command"><strong>db_load</strong></span>.
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp55212448"></a>Environment Variables</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp55213992"></a>DB_HOME</h4>
</div>
</div>
</div>
<p>
If the <span class="bold"><strong>-h</strong></span> option is not specified and
the environment variable DB_HOME is set, it is used as the path of the
database home, as described in the
<a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> method.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp55192880"></a>Supported Keywords</h3>
</div>
</div>
</div>
<p>
The following keywords are supported for the <span class="bold"><strong>-c</strong></span> command-line
option to the <span class="command"><strong>db_load</strong></span> utility. See the
<a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> method
for further discussion of these keywords and what values should be
specified.
</p>
<p>
The parenthetical listing specifies how the value part of the <span class="bold"><strong>name=value</strong></span> pair is interpreted. Items listed as (boolean)
expect value to be <span class="bold"><strong>1</strong></span> (set) or <span class="bold"><strong>0</strong></span> (unset). Items listed as (number) convert value to a
number. Items listed as (string) use the string value without modification.
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<span class="bold"><strong>bt_minkey (number)</strong></span>
</p>
<p>
The minimum number of keys per page.
</p>
</li>
<li>
<p>
<span class="bold"><strong>chksum (boolean)</strong></span>
</p>
<p>
Enable page checksums.
</p>
</li>
<li>
<p>
<span class="bold"><strong>database (string)</strong></span>
</p>
<p>
The database to load.
</p>
</li>
<li>
<p>
<span class="bold"><strong>db_lorder (number)</strong></span>
</p>
<p>
The byte order for integers in the stored database metadata.
For big endian systems, the order should be 4,321 while
for little endian systems is should be 1,234.
</p>
</li>
<li>
<p>
<span class="bold"><strong>db_pagesize (number)</strong></span>
</p>
<p>
The size of database pages, in bytes.
</p>
</li>
<li>
<p>
<span class="bold"><strong>duplicates (boolean)</strong></span>
</p>
<p>
The value of the
<a class="link" href="dbset_flags.html#dbset_flags_DB_DUP">DB_DUP</a>
flag.
</p>
</li>
<li>
<p>
<span class="bold"><strong>dupsort (boolean)</strong></span>
</p>
<p>
The value of the
<a class="link" href="dbset_flags.html#dbset_flags_DB_DUPSORT">DB_DUPSORT</a>
flag.
</p>
</li>
<li>
<p>
<span class="bold"><strong>extentsize (number)</strong></span>
</p>
<p>
The size of database extents, in pages, for Queue databases configured to use
extents.
</p>
</li>
<li>
<p>
<span class="bold"><strong>h_ffactor (number)</strong></span>
</p>
<p>
The density within the Hash database.
</p>
</li>
<li>
<p>
<span class="bold"><strong>h_nelem (number)</strong></span>
</p>
<p>
The size of the Hash database.
</p>
</li>
<li>
<p>
<span class="bold"><strong>keys (boolean)</strong></span>
</p>
<p>
Specify whether keys are present for Queue or Recno databases.
</p>
</li>
<li>
<p>
<span class="bold"><strong>re_len (number)</strong></span>
</p>
<p>
Specify the length for fixed-length records. This
number represents different things, depending on the
access method the database is using. See the
<a class="xref" href="dbset_re_len.html" title="DB->set_re_len()">DB->set_re_len()</a>
method for details on what this number represents.
</p>
</li>
<li>
<p>
<span class="bold"><strong>re_pad (string)</strong></span>
</p>
<p>
Specify the fixed-length record pad character.
</p>
</li>
<li>
<p>
<span class="bold"><strong>recnum (boolean)</strong></span>
</p>
<p>
The value of the
<a class="link" href="dbset_flags.html#dbset_flags_DB_RECNUM">DB_RECNUM</a>
flag.
</p>
</li>
<li>
<p>
<span class="bold"><strong>renumber (boolean)</strong></span>
</p>
<p>
The value of the
<a class="link" href="dbset_flags.html#dbset_flags_DB_RECNUM">DB_RENUMBER</a>
flag.
</p>
</li>
<li>
<p>
<span class="bold"><strong>subdatabase (string)</strong></span>
</p>
<p>
The subdatabase to load.
</p>
</li>
</ul>
</div>
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