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+<!DOCTYPE html>
+<html><head>
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+<link href="../sqlite.css" rel="stylesheet">
+<title>Open A BLOB For Incremental I/O</title>
+<!-- path=../ -->
+</head>
+<body>
+<div class=nosearch>
+<a href="../index.html">
+<img class="logo" src="../images/sqlite370_banner.gif" alt="SQLite" border="0">
+</a>
+<div><!-- IE hack to prevent disappearing logo --></div>
+<div class="tagline desktoponly">
+Small. Fast. Reliable.<br>Choose any three.
+</div>
+<div class="menu mainmenu">
+<ul>
+<li><a href="../index.html">Home</a>
+<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a>
+<li class='wideonly'><a href='../about.html'>About</a>
+<li class='desktoponly'><a href="../docs.html">Documentation</a>
+<li class='desktoponly'><a href="../download.html">Download</a>
+<li class='wideonly'><a href='../copyright.html'>License</a>
+<li class='desktoponly'><a href="../support.html">Support</a>
+<li class='desktoponly'><a href="../prosupport.html">Purchase</a>
+<li class='search' id='search_menubutton'>
+<a href="javascript:void(0)" onclick='toggle_search()'>Search</a>
+</ul>
+</div>
+<div class="menu submenu" id="submenu">
+<ul>
+<li><a href='../about.html'>About</a>
+<li><a href='../docs.html'>Documentation</a>
+<li><a href='../download.html'>Download</a>
+<li><a href='../support.html'>Support</a>
+<li><a href='../prosupport.html'>Purchase</a>
+</ul>
+</div>
+<div class="searchmenu" id="searchmenu">
+<form method="GET" action="../search">
+<select name="s" id="searchtype">
+<option value="d">Search Documentation</option>
+<option value="c">Search Changelog</option>
+</select>
+<input type="text" name="q" id="searchbox" value="">
+<input type="submit" value="Go">
+</form>
+</div>
+</div>
+<script>
+function toggle_div(nm) {
+var w = document.getElementById(nm);
+if( w.style.display=="block" ){
+w.style.display = "none";
+}else{
+w.style.display = "block";
+}
+}
+function toggle_search() {
+var w = document.getElementById("searchmenu");
+if( w.style.display=="block" ){
+w.style.display = "none";
+} else {
+w.style.display = "block";
+setTimeout(function(){
+document.getElementById("searchbox").focus()
+}, 30);
+}
+}
+function div_off(nm){document.getElementById(nm).style.display="none";}
+window.onbeforeunload = function(e){div_off("submenu");}
+/* Disable the Search feature if we are not operating from CGI, since */
+/* Search is accomplished using CGI and will not work without it. */
+if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){
+document.getElementById("search_menubutton").style.display = "none";
+}
+/* Used by the Hide/Show button beside syntax diagrams, to toggle the */
+function hideorshow(btn,obj){
+var x = document.getElementById(obj);
+var b = document.getElementById(btn);
+if( x.style.display!='none' ){
+x.style.display = 'none';
+b.innerHTML='show';
+}else{
+x.style.display = '';
+b.innerHTML='hide';
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+return false;
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+function antiRobotGo(){
+if( antiRobot!=3 ) return;
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+if(j && j.hasAttribute("data-href")) j.href=j.getAttribute("data-href");
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+function antiRobotDefense(){
+document.body.onmousedown=function(){
+antiRobot |= 2;
+antiRobotGo();
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+antiRobot |= 2;
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+setTimeout(function(){
+antiRobot |= 1;
+antiRobotGo();
+}, 100)
+antiRobotGo();
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+antiRobotDefense();
+</script>
+<!-- keywords: sqlite3_blob_open -->
+<div class=nosearch>
+<a href="../c3ref/intro.html"><h2>SQLite C Interface</h2></a>
+<h2>Open A BLOB For Incremental I/O</h2>
+</div>
+<blockquote><pre>
+int sqlite3_blob_open(
+ sqlite3*,
+ const char *zDb,
+ const char *zTable,
+ const char *zColumn,
+ sqlite3_int64 iRow,
+ int flags,
+ sqlite3_blob **ppBlob
+);
+</pre></blockquote>
+<p>
+This interfaces opens a <a href="../c3ref/blob.html">handle</a> to the BLOB located
+in row iRow, column zColumn, table zTable in database zDb;
+in other words, the same BLOB that would be selected by:</p>
+
+<p><pre>
+SELECT zColumn FROM zDb.zTable WHERE <a href="../lang_createtable.html#rowid">rowid</a> = iRow;
+</pre></p>
+
+<p>Parameter zDb is not the filename that contains the database, but
+rather the symbolic name of the database. For attached databases, this is
+the name that appears after the AS keyword in the <a href="../lang_attach.html">ATTACH</a> statement.
+For the main database file, the database name is "main". For TEMP
+tables, the database name is "temp".</p>
+
+<p>If the flags parameter is non-zero, then the BLOB is opened for read
+and write access. If the flags parameter is zero, the BLOB is opened for
+read-only access.</p>
+
+<p>On success, <a href="../rescode.html#ok">SQLITE_OK</a> is returned and the new <a href="../c3ref/blob.html">BLOB handle</a> is stored
+in *ppBlob. Otherwise an <a href="../rescode.html">error code</a> is returned and, unless the error
+code is SQLITE_MISUSE, *ppBlob is set to NULL. This means that, provided
+the API is not misused, it is always safe to call <a href="../c3ref/blob_close.html">sqlite3_blob_close()</a>
+on *ppBlob after this function it returns.</p>
+
+<p>This function fails with SQLITE_ERROR if any of the following are true:
+<ul>
+<li> Database zDb does not exist,
+<li> Table zTable does not exist within database zDb,
+<li> Table zTable is a WITHOUT ROWID table,
+<li> Column zColumn does not exist,
+<li> Row iRow is not present in the table,
+<li> The specified column of row iRow contains a value that is not
+a TEXT or BLOB value,
+<li> Column zColumn is part of an index, PRIMARY KEY or UNIQUE
+constraint and the blob is being opened for read/write access,
+<li> <a href="../foreignkeys.html">Foreign key constraints</a> are enabled,
+column zColumn is part of a <a href="../foreignkeys.html#parentchild">child key</a> definition and the blob is
+being opened for read/write access.
+</ul></p>
+
+<p>Unless it returns SQLITE_MISUSE, this function sets the
+<a href="../c3ref/sqlite3.html">database connection</a> error code and message accessible via
+<a href="../c3ref/errcode.html">sqlite3_errcode()</a> and <a href="../c3ref/errcode.html">sqlite3_errmsg()</a> and related functions.</p>
+
+<p>A BLOB referenced by sqlite3_blob_open() may be read using the
+<a href="../c3ref/blob_read.html">sqlite3_blob_read()</a> interface and modified by using
+<a href="../c3ref/blob_write.html">sqlite3_blob_write()</a>. The <a href="../c3ref/blob.html">BLOB handle</a> can be moved to a
+different row of the same table using the <a href="../c3ref/blob_reopen.html">sqlite3_blob_reopen()</a>
+interface. However, the column, table, or database of a <a href="../c3ref/blob.html">BLOB handle</a>
+cannot be changed after the <a href="../c3ref/blob.html">BLOB handle</a> is opened.</p>
+
+<p>If the row that a BLOB handle points to is modified by an
+<a href="../lang_update.html">UPDATE</a>, <a href="../lang_delete.html">DELETE</a>, or by <a href="../lang_conflict.html">ON CONFLICT</a> side-effects
+then the BLOB handle is marked as "expired".
+This is true if any column of the row is changed, even a column
+other than the one the BLOB handle is open on.
+Calls to <a href="../c3ref/blob_read.html">sqlite3_blob_read()</a> and <a href="../c3ref/blob_write.html">sqlite3_blob_write()</a> for
+an expired BLOB handle fail with a return code of <a href="../rescode.html#abort">SQLITE_ABORT</a>.
+Changes written into a BLOB prior to the BLOB expiring are not
+rolled back by the expiration of the BLOB. Such changes will eventually
+commit if the transaction continues to completion.</p>
+
+<p>Use the <a href="../c3ref/blob_bytes.html">sqlite3_blob_bytes()</a> interface to determine the size of
+the opened blob. The size of a blob may not be changed by this
+interface. Use the <a href="../lang_update.html">UPDATE</a> SQL command to change the size of a
+blob.</p>
+
+<p>The <a href="../c3ref/bind_blob.html">sqlite3_bind_zeroblob()</a> and <a href="../c3ref/result_blob.html">sqlite3_result_zeroblob()</a> interfaces
+and the built-in <a href="../lang_corefunc.html#zeroblob">zeroblob</a> SQL function may be used to create a
+zero-filled blob to read or write using the incremental-blob interface.</p>
+
+<p>To avoid a resource leak, every open <a href="../c3ref/blob.html">BLOB handle</a> should eventually
+be released by a call to <a href="../c3ref/blob_close.html">sqlite3_blob_close()</a>.</p>
+
+<p>See also: <a href="../c3ref/blob_close.html">sqlite3_blob_close()</a>,
+<a href="../c3ref/blob_reopen.html">sqlite3_blob_reopen()</a>, <a href="../c3ref/blob_read.html">sqlite3_blob_read()</a>,
+<a href="../c3ref/blob_bytes.html">sqlite3_blob_bytes()</a>, <a href="../c3ref/blob_write.html">sqlite3_blob_write()</a>.
+</p><p>See also lists of
+ <a href="../c3ref/objlist.html">Objects</a>,
+ <a href="../c3ref/constlist.html">Constants</a>, and
+ <a href="../c3ref/funclist.html">Functions</a>.</p>
+