SQLite

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.43 2005/03/31 21:02:46 drh Exp $
*/

/*
** The default size of a database page.
*/
#ifndef SQLITE_DEFAULT_PAGE_SIZE
# define SQLITE_DEFAULT_PAGE_SIZE 1024
#endif

/* Maximum page size.  The upper bound on this value is 32768.  This a limit
** imposed by necessity of storing the value in a 2-byte unsigned integer
** and the fact that the page size must be a power of 2.
**
** This value is used to initialize certain arrays on the stack at
** various places in the code.  On embedded machines where stack space
** is limited and the flexibility of having large pages is not needed,
** it makes good sense to reduce the maximum page size to something more
** reasonable, like 1024.
*/
#ifndef SQLITE_MAX_PAGE_SIZE
# define SQLITE_MAX_PAGE_SIZE 8192
#endif

/*
** Maximum number of pages in one database.

#
# Run this Tcl script to generate the pragma.html file.
#
set rcsid {$Id: pragma.tcl,v 1.13 2005/03/31 21:02:46 drh Exp $}
source common.tcl
header {Pragma statements supported by SQLite}

proc Section {name {label {}}} {
  puts "\n<hr />"
  if {$label!=""} {
    puts "<a name=\"$label\"></a>"

<a name="pragma_page_size"></a>
<li><p><b>PRAGMA page_size;
       <br>PRAGMA page_size = </b><i>bytes</i><b>;</b></p>
    <p>Query or set the page-size of the database. The page-size
    may only be set if the database has not yet been created. The page
    size must be a power of two greater than or equal to 512 and less
    than or equal to 8192. The upper limit may be modified by setting
    the value of macro SQLITE_MAX_PAGE_SIZE during compilation.  The
    maximum upper bound is 32768.
    </p>
</li>

<a name="pragma_short_column_names"></a>
<li><p><b>PRAGMA short_column_names;
       <br>PRAGMA short_column_names = </b><i>0 | 1</i><b>;</b></p>
    <p>Query or change the short-column-names flag. This flag affects

data is stored in the leaves of the tree instead of in both the leaves and
the intermediate branch nodes.  The use of B+trees for tables allows for
better scalability and the storage of larger data fields without the use of
overflow pages.  Traditional B-trees are still used for indices.</p>

<p>
The new file format also supports variable pages sizes between 512 and
32768 bytes.  The size of a page is stored in the file header so the
same library can read databases with different pages sizes, in theory,
though this feature has not yet been implemented in practice.
</p>

<p>
The new file format omits unused fields from its disk images.  For example,
indices use only the key part of a B-tree record and not the data.  So

<p>
SQLite version 3.0 is made possible in part by AOL developers
supporting and embracing great Open-Source Software.
</p>


}
footer {$Id: version3.tcl,v 1.5 2005/03/31 21:02:46 drh Exp $}