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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<a href="intro.html"><h2>SQLite C Interface</h2></a>
<h2>Prepared Statement Scan Status</h2>
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<blockquote><pre>
int sqlite3_stmt_scanstatus(
sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
int idx, /* Index of loop to report on */
int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
void *pOut /* Result written here */
);
</pre></blockquote>
<p>
This interface returns information about the predicted and measured
performance for pStmt. Advanced applications can use this
interface to compare the predicted and the measured performance and
issue warnings and/or rerun <a href="../lang_analyze.html">ANALYZE</a> if discrepancies are found.</p>
<p>Since this interface is expected to be rarely used, it is only
available if SQLite is compiled using the <a href="../compile.html#enable_stmt_scanstatus">SQLITE_ENABLE_STMT_SCANSTATUS</a>
compile-time option.</p>
<p>The "iScanStatusOp" parameter determines which status information to return.
The "iScanStatusOp" must be one of the <a href="../c3ref/c_scanstat_est.html">scanstatus options</a> or the behavior
of this interface is undefined.
The requested measurement is written into a variable pointed to by
the "pOut" parameter.
Parameter "idx" identifies the specific loop to retrieve statistics for.
Loops are numbered starting from zero. If idx is out of range - less than
zero or greater than or equal to the total number of loops used to implement
the statement - a non-zero value is returned and the variable that pOut
points to is unchanged.</p>
<p>Statistics might not be available for all loops in all statements. In cases
where there exist loops with no available statistics, this function behaves
as if the loop did not exist - it returns non-zero and leave the variable
that pOut points to unchanged.</p>
<p>See also: <a href="../c3ref/stmt_scanstatus_reset.html">sqlite3_stmt_scanstatus_reset()</a>
</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>