Alessandro Bonazzi 5c7aa8c1c0 Patch level : 12.0 no-patch
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Aggiunta documentazione di sqlite 3
2020-11-29 00:32:36 +01:00

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<title>Version Numbers in SQLite</title>
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Version Numbers in SQLite
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<h1 id="sqlite_version_numbers"><span>1. </span>SQLite Version Numbers</h1>
<p>
Beginning with <a href="releaselog/3_9_0.html">version 3.9.0</a> (2015-10-14) SQLite uses
<a href="http://semver.org">semantic versioning</a>.
Prior to that time, SQLite employed a version identifier that
contained between two and four numbers.
</p><h2 id="the_new_version_numbering_system_after_dateof_3_9_0_"><span>1.1. </span>The New Version Numbering System (After 2015-10-14)</h2>
<p>
All SQLite releases starting with 3.9.0 use a three-number
"<a href="http://semver.org">semantic version</a>" of the form X.Y.Z.
The first number X is only increased when there is a change that
breaks backward compatibility. The
current value for X is 3, and the SQLite developers plan to support
the current SQLite database file format, SQL syntax, and C interface
through <a href="lts.html">at least the year 2050</a>. Hence, one
can expect that all future versions of SQLite for the next several
decades will begin with "3.".
</p><p>
The second number Y is incremented for any change that breaks forward
compatibility by adding new features.
Most future SQLite releases are expected
to increment the second number Y. The Z is reset to zero whenever Y
is increased.
</p><p>
The third number Z is incremented for releases consisting of only
small changes that implement performance enhancements and/or bug fixes.
</p><p>
The rate of enhancement for SQLite over the previous five years
(2010-2015) is approximately 6 increments of Y per year. The
numbering format used by for <a href="c3ref/c_source_id.html">SQLITE_VERSION_NUMBER</a> and
<a href="c3ref/libversion.html">sqlite3_libversion_number()</a> allows versions up to 3.999.999, which is
more than enough for the planned end-of-support date for SQLite
in 2050. However, the current tarball naming conventions only
reserve two digits for the Y and so the naming format for downloads
will need to be revised in about 2030.
</p><h2 id="the_historical_numbering_system_before_dateof_3_9_0_"><span>1.2. </span>The Historical Numbering System (Before 2015-10-14)</h2>
<p>This historical version numbering system used a two-, three-,
or four-number version: W.X, W.X.Y, or W.X.Y.Z.
W was the file format: 1 or 2 or 3.
X was the major version.
Y was the minor version.
Z was used only for patch releases to fix bugs.
</p><p>
There have been three historical file formats for SQLite.
SQLite 1.0 through 1.0.32 used the
<a href="https://www.gnu.org/software/gdbm/gdbm.html">gdbm</a> library as its storage
engine.
SQLite 2.0.0 through 2.8.17 used a custom b-tree storage engine that
supported only text keys and data.
All modern versions of SQLite (3.0.0 to present) use a b-tree storage
engine that has full support for binary data and Unicode.
</p><p>
This major version number X was historically incremented only for
large and important changes to the code. What constituted "large
and important" was subjective. The 3.6.23 to 3.7.0 change
was a result of adding support for <a href="wal.html">WAL mode</a>.
The 3.7.17 to 3.8.0 change was a result of rewrite known as the
<a href="queryplanner-ng.html">next generation query planner</a>.
</p><p>
The minor version number Y was historically incremented for new
features and/or new interfaces that did not significantly change
the structure of the code. The addition of <a href="lang_with.html">common table expressions</a>,
<a href="partialindex.html">partial indexes</a>, and <a href="expridx.html">indexes on expressions</a> are all examples of
"minor" changes. Again, the distinction between "major" and "minor"
is subjective.
</p><p>
The patch level Z was historically only used for bug-fix releases
that changed only a small number of code lines.
</p><h2 id="version_history"><span>1.3. </span>Version History</h2>
<ul>
<li><a href="chronology.html">Chronology</a>
</li><li><a href="changes.html">Change log</a>
</li></ul>