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<a href="intro.html"><h2>Session Module C Interface</h2></a><h2>Obtain old.* Values From A Changeset Iterator</h2><blockquote><pre>int sqlite3changeset_old(
sqlite3_changeset_iter *pIter, /* Changeset iterator */
int iVal, /* Column number */
sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */
);
</pre></blockquote><p>
The pIter argument passed to this function may either be an iterator
passed to a conflict-handler by <a href="../session/sqlite3changeset_apply.html">sqlite3changeset_apply()</a>, or an iterator
created by <a href="../session/sqlite3changeset_start.html">sqlite3changeset_start()</a>. In the latter case, the most recent
call to <a href="../session/sqlite3changeset_next.html">sqlite3changeset_next()</a> must have returned SQLITE_ROW.
Furthermore, it may only be called if the type of change that the iterator
currently points to is either <a href="../c3ref/c_alter_table.html">SQLITE_DELETE</a> or <a href="../c3ref/c_alter_table.html">SQLITE_UPDATE</a>. Otherwise,
this function returns <a href="../rescode.html#misuse">SQLITE_MISUSE</a> and sets *ppValue to NULL.</p>
<p>Argument iVal must be greater than or equal to 0, and less than the number
of columns in the table affected by the current change. Otherwise,
<a href="../rescode.html#range">SQLITE_RANGE</a> is returned and *ppValue is set to NULL.</p>
<p>If successful, this function sets *ppValue to point to a protected
sqlite3_value object containing the iVal'th value from the vector of
original row values stored as part of the UPDATE or DELETE change and
returns SQLITE_OK. The name of the function comes from the fact that this
is similar to the "old.*" columns available to update or delete triggers.</p>
<p>If some other error occurs (e.g. an OOM condition), an SQLite error code
is returned and *ppValue is set to NULL.
</p><p>See also lists of
<a href="objlist.html">Objects</a>,
<a href="constlist.html">Constants</a>, and
<a href="funclist.html">Functions</a>.</p>
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