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+<title>Obtaining SQL Values</title>
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+<!-- keywords: sqlite3_value_blob sqlite3_value_bytes sqlite3_value_bytes16 sqlite3_value_double sqlite3_value_encoding sqlite3_value_frombind sqlite3_value_int sqlite3_value_int64 sqlite3_value_nochange sqlite3_value_numeric_type sqlite3_value_pointer sqlite3_value_text sqlite3_value_text16 sqlite3_value_text16be sqlite3_value_text16le sqlite3_value_type -->
+<div class=nosearch>
+<a href="intro.html"><h2>SQLite C Interface</h2></a>
+<h2>Obtaining SQL Values</h2>
+</div>
+<blockquote><pre>
+const void *sqlite3_value_blob(sqlite3_value*);
+double sqlite3_value_double(sqlite3_value*);
+int sqlite3_value_int(sqlite3_value*);
+sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
+void *sqlite3_value_pointer(sqlite3_value*, const char*);
+const unsigned char *sqlite3_value_text(sqlite3_value*);
+const void *sqlite3_value_text16(sqlite3_value*);
+const void *sqlite3_value_text16le(sqlite3_value*);
+const void *sqlite3_value_text16be(sqlite3_value*);
+int sqlite3_value_bytes(sqlite3_value*);
+int sqlite3_value_bytes16(sqlite3_value*);
+int sqlite3_value_type(sqlite3_value*);
+int sqlite3_value_numeric_type(sqlite3_value*);
+int sqlite3_value_nochange(sqlite3_value*);
+int sqlite3_value_frombind(sqlite3_value*);
+int sqlite3_value_encoding(sqlite3_value*);
+</pre></blockquote>
+<p>
+<b>Summary:</b>
+<blockquote><table border=0 cellpadding=0 cellspacing=0>
+<tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
+<tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
+<tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
+<tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
+<tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
+<tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
+<tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
+the native byteorder
+<tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
+<tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
+<tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
+<tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
+or a UTF-8 TEXT in bytes
+<tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
+<td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
+TEXT in bytes
+<tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
+datatype of the value
+<tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
+<td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
+<tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
+<td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
+against a virtual table.
+<tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
+<td>&rarr;&nbsp;&nbsp;<td>True if value originated from a <a href="../lang_expr.html#varparam">bound parameter</a>
+</table></blockquote></p>
+
+<p><b>Details:</b></p>
+
+<p>These routines extract type, size, and content information from
+<a href="../c3ref/value.html">protected sqlite3_value</a> objects. Protected sqlite3_value objects
+are used to pass parameter information into the functions that
+implement <a href="../appfunc.html">application-defined SQL functions</a> and <a href="../vtab.html">virtual tables</a>.</p>
+
+<p>These routines work only with <a href="../c3ref/value.html">protected sqlite3_value</a> objects.
+Any attempt to use these routines on an <a href="../c3ref/value.html">unprotected sqlite3_value</a>
+is not threadsafe.</p>
+
+<p>These routines work just like the corresponding <a href="../c3ref/column_blob.html">column access functions</a>
+except that these routines take a single <a href="../c3ref/value.html">protected sqlite3_value</a> object
+pointer instead of a <a href="../c3ref/stmt.html">sqlite3_stmt*</a> pointer and an integer column number.</p>
+
+<p>The sqlite3_value_text16() interface extracts a UTF-16 string
+in the native byte-order of the host machine. The
+sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
+extract UTF-16 strings as big-endian and little-endian respectively.</p>
+
+<p>If <a href="../c3ref/value.html">sqlite3_value</a> object V was initialized
+using <a href="../c3ref/bind_blob.html">sqlite3_bind_pointer(S,I,P,X,D)</a> or <a href="../c3ref/result_blob.html">sqlite3_result_pointer(C,P,X,D)</a>
+and if X and Y are strings that compare equal according to strcmp(X,Y),
+then sqlite3_value_pointer(V,Y) will return the pointer P. Otherwise,
+sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
+routine is part of the <a href="../bindptr.html">pointer passing interface</a> added for SQLite 3.20.0.</p>
+
+<p>The sqlite3_value_type(V) interface returns the
+<a href="../c3ref/c_blob.html">datatype code</a> for the initial datatype of the
+<a href="../c3ref/value.html">sqlite3_value</a> object V. The returned value is one of <a href="../c3ref/c_blob.html">SQLITE_INTEGER</a>,
+<a href="../c3ref/c_blob.html">SQLITE_FLOAT</a>, <a href="../c3ref/c_blob.html">SQLITE_TEXT</a>, <a href="../c3ref/c_blob.html">SQLITE_BLOB</a>, or <a href="../c3ref/c_blob.html">SQLITE_NULL</a>.
+Other interfaces might change the datatype for an sqlite3_value object.
+For example, if the datatype is initially SQLITE_INTEGER and
+sqlite3_value_text(V) is called to extract a text value for that
+integer, then subsequent calls to sqlite3_value_type(V) might return
+SQLITE_TEXT. Whether or not a persistent internal datatype conversion
+occurs is undefined and may change from one release of SQLite to the next.</p>
+
+<p>The sqlite3_value_numeric_type() interface attempts to apply
+numeric affinity to the value. This means that an attempt is
+made to convert the value to an integer or floating point. If
+such a conversion is possible without loss of information (in other
+words, if the value is a string that looks like a number)
+then the conversion is performed. Otherwise no conversion occurs.
+The <a href="../c3ref/c_blob.html">datatype</a> after conversion is returned.</p>
+
+<p>The sqlite3_value_encoding(X) interface returns one of <a href="../c3ref/c_any.html">SQLITE_UTF8</a>,
+<a href="../c3ref/c_any.html">SQLITE_UTF16BE</a>, or <a href="../c3ref/c_any.html">SQLITE_UTF16LE</a> according to the current encoding
+of the value X, assuming that X has type TEXT. If sqlite3_value_type(X)
+returns something other than SQLITE_TEXT, then the return value from
+sqlite3_value_encoding(X) is meaningless. Calls to
+sqlite3_value_text(X), sqlite3_value_text16(X), sqlite3_value_text16be(X),
+sqlite3_value_text16le(X), sqlite3_value_bytes(X), or
+sqlite3_value_bytes16(X) might change the encoding of the value X and
+thus change the return from subsequent calls to sqlite3_value_encoding(X).</p>
+
+<p>Within the <a href="../vtab.html#xupdate">xUpdate</a> method of a <a href="../vtab.html">virtual table</a>, the
+sqlite3_value_nochange(X) interface returns true if and only if
+the column corresponding to X is unchanged by the UPDATE operation
+that the xUpdate method call was invoked to implement and if
+and the prior <a href="../vtab.html#xcolumn">xColumn</a> method call that was invoked to extracted
+the value for that column returned without setting a result (probably
+because it queried <a href="../c3ref/vtab_nochange.html">sqlite3_vtab_nochange()</a> and found that the column
+was unchanging). Within an <a href="../vtab.html#xupdate">xUpdate</a> method, any value for which
+sqlite3_value_nochange(X) is true will in all other respects appear
+to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
+than within an <a href="../vtab.html#xupdate">xUpdate</a> method call for an UPDATE statement, then
+the return value is arbitrary and meaningless.</p>
+
+<p>The sqlite3_value_frombind(X) interface returns non-zero if the
+value X originated from one of the <a href="../c3ref/bind_blob.html">sqlite3_bind()</a>
+interfaces. If X comes from an SQL literal value, or a table column,
+or an expression, then sqlite3_value_frombind(X) returns zero.</p>
+
+<p>Please pay particular attention to the fact that the pointer returned
+from <a href="../c3ref/value_blob.html">sqlite3_value_blob()</a>, <a href="../c3ref/value_blob.html">sqlite3_value_text()</a>, or
+<a href="../c3ref/value_blob.html">sqlite3_value_text16()</a> can be invalidated by a subsequent call to
+<a href="../c3ref/value_blob.html">sqlite3_value_bytes()</a>, <a href="../c3ref/value_blob.html">sqlite3_value_bytes16()</a>, <a href="../c3ref/value_blob.html">sqlite3_value_text()</a>,
+or <a href="../c3ref/value_blob.html">sqlite3_value_text16()</a>.</p>
+
+<p>These routines must be called from the same thread as
+the SQL function that supplied the <a href="../c3ref/value.html">sqlite3_value*</a> parameters.</p>
+
+<p>As long as the input parameter is correct, these routines can only
+fail if an out-of-memory error occurs during a format conversion.
+Only the following subset of interfaces are subject to out-of-memory
+errors:</p>
+
+<p><ul>
+<li> sqlite3_value_blob()
+<li> sqlite3_value_text()
+<li> sqlite3_value_text16()
+<li> sqlite3_value_text16le()
+<li> sqlite3_value_text16be()
+<li> sqlite3_value_bytes()
+<li> sqlite3_value_bytes16()
+</ul></p>
+
+<p>If an out-of-memory error occurs, then the return value from these
+routines is the same as if the column had contained an SQL NULL value.
+Valid SQL NULL returns can be distinguished from out-of-memory errors
+by invoking the <a href="../c3ref/errcode.html">sqlite3_errcode()</a> immediately after the suspect
+return value is obtained and before any
+other SQLite interface is called on the same <a href="../c3ref/sqlite3.html">database connection</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>
+