204 lines
8.2 KiB
HTML
204 lines
8.2 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
<html>
|
|
<head>
|
|
<link rel="STYLESHEET" href="cx_Oracle.css" type='text/css' />
|
|
<link rel="first" href="cx_Oracle.html" title='cx_Oracle' />
|
|
<link rel='contents' href='contents.html' title="Contents" />
|
|
<link rel='last' href='about.html' title='About this document...' />
|
|
<link rel='help' href='about.html' title='About this document...' />
|
|
<link rel="next" href="dateobj.html" />
|
|
<link rel="prev" href="sesspool.html" />
|
|
<link rel="parent" href="cx_Oracle.html" />
|
|
<link rel="next" href="dateobj.html" />
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<meta name='aesop' content='information' />
|
|
<title>6. LOB Objects</title>
|
|
</head>
|
|
<body>
|
|
<div class="navigation">
|
|
<div id='top-navigation-panel' xml:id='top-navigation-panel'>
|
|
<table align="center" width="100%" cellpadding="0" cellspacing="2">
|
|
<tr>
|
|
<td class='online-navigation'><a rel="prev" title="5. sessionpool Objects"
|
|
href="sesspool.html"><img src='previous.png'
|
|
border='0' height='32' alt='Previous Page' width='32' /></a></td>
|
|
<td class='online-navigation'><a rel="parent" title="cx_Oracle"
|
|
href="cx_Oracle.html"><img src='up.png'
|
|
border='0' height='32' alt='Up one Level' width='32' /></a></td>
|
|
<td class='online-navigation'><a rel="next" title="7. date Objects"
|
|
href="dateobj.html"><img src='next.png'
|
|
border='0' height='32' alt='Next Page' width='32' /></a></td>
|
|
<td align="center" width="100%">cx_Oracle</td>
|
|
<td class='online-navigation'><a rel="contents" title="Table of Contents"
|
|
href="contents.html"><img src='contents.png'
|
|
border='0' height='32' alt='Contents' width='32' /></a></td>
|
|
<td class='online-navigation'><img src='blank.png'
|
|
border='0' height='32' alt='' width='32' /></td>
|
|
<td class='online-navigation'><img src='blank.png'
|
|
border='0' height='32' alt='' width='32' /></td>
|
|
</tr></table>
|
|
<div class='online-navigation'>
|
|
<b class="navlabel">Previous:</b>
|
|
<a class="sectref" rel="prev" href="sesspool.html">5. SessionPool Objects</a>
|
|
<b class="navlabel">Up:</b>
|
|
<a class="sectref" rel="parent" href="cx_Oracle.html">cx_Oracle</a>
|
|
<b class="navlabel">Next:</b>
|
|
<a class="sectref" rel="next" href="dateobj.html">7. Date Objects</a>
|
|
</div>
|
|
<hr /></div>
|
|
</div>
|
|
<!--End of Navigation Panel-->
|
|
|
|
<h1><a name="SECTION008000000000000000000"></a><a name="lobobj"></a>
|
|
<br>
|
|
6. LOB Objects
|
|
</h1>
|
|
|
|
<p>
|
|
<strong>NOTE</strong>: This object is an extension the DB API. It is returned whenever
|
|
Oracle CLOB, BLOB and BFILE columns are fetched.
|
|
|
|
<p>
|
|
<strong>NOTE</strong>: Internally, Oracle uses LOB locators which are allocated based
|
|
on the cursor array size. Thus, it is important that the data in the LOB object
|
|
be manipulated before another internal fetch takes place. The safest way to do
|
|
this is to use the cursor as an iterator. In particular, do not use the
|
|
fetchall() method. The exception "LOB variable no longer valid after
|
|
subsequent fetch" will be raised if an attempt to access a LOB variable after
|
|
a subsequent fetch is detected.
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-139' xml:id='l2h-139' class="function">close</tt></b>(</nobr></td>
|
|
<td><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Close the LOB. Call this when writing is completed so that the indexes
|
|
associated with the LOB can be updated.
|
|
</dl>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-140' xml:id='l2h-140' class="function">fileexists</tt></b>(</nobr></td>
|
|
<td><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Return a boolean indicating if the file referenced by the BFILE type LOB
|
|
exists.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-141' xml:id='l2h-141' class="function">getchunksize</tt></b>(</nobr></td>
|
|
<td><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Return the chunk size for the internal LOB. Reading and writing to the LOB
|
|
in chunks of multiples of this size will improve performance.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-142' xml:id='l2h-142' class="function">getfilename</tt></b>(</nobr></td>
|
|
<td><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Return a two-tuple consisting of the directory alias and file name for a
|
|
BFILE type LOB.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-143' xml:id='l2h-143' class="function">isopen</tt></b>(</nobr></td>
|
|
<td><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Return a boolean indicating if the LOB is opened.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-144' xml:id='l2h-144' class="function">open</tt></b>(</nobr></td>
|
|
<td><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Open the LOB for writing. This will improve performance when writing to a LOB
|
|
in chunks and there are functional or extensible indexes associated with the
|
|
LOB.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-145' xml:id='l2h-145' class="function">read</tt></b>(</nobr></td>
|
|
<td><var></var><big>[</big><var><var>offset = 1</var>, </var><big>[</big><var><var>amount</var></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Return a portion (or all) of the data in the LOB object.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-146' xml:id='l2h-146' class="function">setfilename</tt></b>(</nobr></td>
|
|
<td><var><var>dirAlias</var>, <var>name</var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Set the directory alias and name of the BFILE type LOB.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-147' xml:id='l2h-147' class="function">size</tt></b>(</nobr></td>
|
|
<td><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Returns the size of the data in the LOB object.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-148' xml:id='l2h-148' class="function">trim</tt></b>(</nobr></td>
|
|
<td><var></var><big>[</big><var><var>newSize = 0</var></var><big>]</big><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Trim the LOB to the new size.
|
|
</dl>
|
|
|
|
<p>
|
|
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
|
|
<td><nobr><b><tt id='l2h-149' xml:id='l2h-149' class="function">write</tt></b>(</nobr></td>
|
|
<td><var><var>data</var>, </var><big>[</big><var><var>offset = 1</var></var><big>]</big><var></var>)</td></tr></table></dt>
|
|
<dd>
|
|
Write the data to the LOB object at the given offset. Note that if you want
|
|
to make the LOB value smaller, you must use the trim() function.
|
|
</dl>
|
|
|
|
<p>
|
|
|
|
<div class="navigation">
|
|
<div class='online-navigation'>
|
|
<p></p><hr />
|
|
<table align="center" width="100%" cellpadding="0" cellspacing="2">
|
|
<tr>
|
|
<td class='online-navigation'><a rel="prev" title="5. sessionpool Objects"
|
|
href="sesspool.html"><img src='previous.png'
|
|
border='0' height='32' alt='Previous Page' width='32' /></a></td>
|
|
<td class='online-navigation'><a rel="parent" title="cx_Oracle"
|
|
href="cx_Oracle.html"><img src='up.png'
|
|
border='0' height='32' alt='Up one Level' width='32' /></a></td>
|
|
<td class='online-navigation'><a rel="next" title="7. date Objects"
|
|
href="dateobj.html"><img src='next.png'
|
|
border='0' height='32' alt='Next Page' width='32' /></a></td>
|
|
<td align="center" width="100%">cx_Oracle</td>
|
|
<td class='online-navigation'><a rel="contents" title="Table of Contents"
|
|
href="contents.html"><img src='contents.png'
|
|
border='0' height='32' alt='Contents' width='32' /></a></td>
|
|
<td class='online-navigation'><img src='blank.png'
|
|
border='0' height='32' alt='' width='32' /></td>
|
|
<td class='online-navigation'><img src='blank.png'
|
|
border='0' height='32' alt='' width='32' /></td>
|
|
</tr></table>
|
|
<div class='online-navigation'>
|
|
<b class="navlabel">Previous:</b>
|
|
<a class="sectref" rel="prev" href="sesspool.html">5. SessionPool Objects</a>
|
|
<b class="navlabel">Up:</b>
|
|
<a class="sectref" rel="parent" href="cx_Oracle.html">cx_Oracle</a>
|
|
<b class="navlabel">Next:</b>
|
|
<a class="sectref" rel="next" href="dateobj.html">7. Date Objects</a>
|
|
</div>
|
|
</div>
|
|
<hr />
|
|
<span class="release-info">Release HEAD, documentation updated on October 1, 2007.</span>
|
|
</div>
|
|
<!--End of Navigation Panel-->
|
|
|
|
</body>
|
|
</html>
|