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Overview
Comment:Rework parts of the pragma documentation. Ticket #1081. (CVS 2354)
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 25141d9e213005940c4e57deca408e09c3e615d1
User & Date: drh 2005-02-19 13:05:48.000
Context
2005-02-19
13:46
Prepare for the release of 3.1.3. (CVS 2355) (check-in: 5b66631fd4 user: drh tags: trunk)
13:05
Rework parts of the pragma documentation. Ticket #1081. (CVS 2354) (check-in: 25141d9e21 user: drh tags: trunk)
12:44
Add documentation on the EXISTS expression. Ticket #1082. (CVS 2353) (check-in: 76cacb4a39 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to www/pragma.tcl. 
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#
# Run this Tcl script to generate the pragma.html file.
#
set rcsid {$Id: pragma.tcl,v 1.10 2005/02/19 12:32:57 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>"




|








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#
# Run this Tcl script to generate the pragma.html file.
#
set rcsid {$Id: pragma.tcl,v 1.11 2005/02/19 13:05:48 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>"
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    to the disk surface.  On the other hand, some
    operations are as much as 50 or more times faster with synchronous OFF.
    </p></li>


<a name="pragma_temp_store"></a>
<li><p><b>PRAGMA temp_store;
       <br>PRAGMA temp_store = DEFAULT; </b>(0)<b>
       <br>PRAGMA temp_store = MEMORY; </b>(2)<b>
       <br>PRAGMA temp_store = FILE;</b> (1)</p>
    <p>Query or change the setting of the "temp_store" flag affecting
    the database for the duration of the current database connection.
    The temp_store flag reverts to its default value when the database
    is closed and reopened.  For additional information on the temp_store
    flag, see the description of the <a href="#pragma_default_temp_store">
    <b>default_temp_store</b></a> pragma.  Note that it is possible for 
    the library compile-time options to override this setting.  

<a name="pragma_temp_store"></a>
<li><p><b>PRAGMA temp_store;
       <br>PRAGMA temp_store = DEFAULT; </b>(0)<b>
       <br>PRAGMA temp_store = MEMORY; </b>(2)<b>
       <br>PRAGMA temp_store = FILE;</b> (1)</p>
    <p>Query or change the setting of the "<b>temp_store</b>" parameter.
    When temp_store is DEFAULT (0), the compile-time value of the
    symbol TEMP_STORE is used for the temporary database.  When

    temp_store is MEMORY (2), an in-memory database is used.  
    When temp_store is FILE (1), a temporary database file on disk
    will be used. See PRAGMA <a href="#pragma_temp_store_directory">
    temp_store_directory</a> for further temporary storage options when 

    <b>FILE</b> is specified. When the temp_store setting is changed,
    all existing temporary tables, indices, triggers, and viewers are
    immediately deleted.</p>

    <p>It is possible for the library compile-time symbol
    TEMP_STORE to override this setting.  The following table summarizes 

    this:</p>


<table cellpadding="2">
<tr><th>TEMP_STORE</th><th>temp_store</th><th>temp database location</th></tr>


<tr><td align="center">0</td><td align="center"><em>any</em></td><td align="center">file</td></tr>


<tr><td align="center">1</td><td align="center">0</td><td align="center">file</td></tr>


<tr><td align="center">1</td><td align="center">1</td><td align="center">file</td></tr>


<tr><td align="center">1</td><td align="center">2</td><td align="center">memory</td></tr>


<tr><td align="center">2</td><td align="center">0</td><td align="center">memory</td></tr>


<tr><td align="center">2</td><td align="center">1</td><td align="center">file</td></tr>


<tr><td align="center">2</td><td align="center">2</td><td align="center">memory</td></tr>


<tr><td align="center">3</td><td align="center"><em>any</em></td><td align="center">memory</td></tr>


</table>

</li>
<br>

<a name="pragma_temp_store_directory"></a>
<li><p><b>PRAGMA temp_store_directory;
       <br>PRAGMA temp_store_directory = 'directory-name';</b></p>
    <p>Query or change the setting of the "temp_store_directory" flag affecting

    the database for the duration of the current database connection.
    The temp_store_directory flag reverts to its default value when the database
    is closed and reopened.  Setting temp_store_directory allows control of the
    placement of temporary files created by SQLite when PRAGMA
    <a href="#pragma_temp_store">temp_store</a> is <b>FILE</b> (1),
    or when the compile time default temporary store is FILE.
    Otherwise, when the temp_store (or default) setting is 
    <b>MEMORY</b> (2), setting temp_store_directory has no effect.</p>

    <p>When the temp_store_directory setting is changed, all existing temporary
    tables, indices, triggers, and viewers are immediately deleted.  In
    practice, temp_store_directory should be set immediately after the 
    database is opened.  </p>

    <p>The value <i>directory-name</i> should be enclosed in single quotes.
    To revert the directory to the default, set the <i>directory-name</i> to
    a null string, e.g., <i>PRAGMA temp_store_directory = ''</i>.  An
    error is raised if <i>directory-name</i> is not found or is not
    writable. </p>

    <p>The default directory for temporary files depends on the OS.  For
    Unix/Linux/OSX, the default is the is the first writable directory found
    in the list of: <b>/var/tmp, /usr/tmp, /tmp,</b> and <b>
    <i>current-directory</i></b>.  For Windows NT, the default 








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    to the disk surface.  On the other hand, some
    operations are as much as 50 or more times faster with synchronous OFF.
    </p></li>


<a name="pragma_temp_store"></a>
<li><p><b>PRAGMA temp_store;
       <br>PRAGMA temp_store = DEFAULT;</b> (0)<b>

       <br>PRAGMA temp_store = FILE;</b> (1)<b>











       <br>PRAGMA temp_store = MEMORY;</b> (2)</p>

    <p>Query or change the setting of the "<b>temp_store</b>" parameter.
    When temp_store is DEFAULT (0), the compile-time C preprocessor macro
    TEMP_STORE is used to determine where temporary tables and indices
    are stored.  When
    temp_store is MEMORY (2) temporary tables and indices are kept in memory.
    When temp_store is FILE (1) temporary tables and indices are stored
    in a file.  The <a href="#pragma_temp_store_directory">
    temp_store_directory</a> pragma can be used to specify the directory
    containing this file.
    <b>FILE</b> is specified. When the temp_store setting is changed,
    all existing temporary tables, indices, triggers, and views are
    immediately deleted.</p>

    <p>It is possible for the library compile-time C preprocessor symbol
    TEMP_STORE to override this pragma setting.  The following table summarizes
    the interaction of the TEMP_STORE preprocessor macro and the
    temp_store pragma:</p>

    <blockquote>
    <table cellpadding="2" border="1">
    <tr><th valign="bottom">TEMP_STORE</th>
        <th valign="bottom">PRAGMA<br>temp_store</th>
        <th>Storage used for<br>TEMP tables and indices</th></tr>
    <tr><td align="center">0</td>
        <td align="center"><em>any</em></td>
        <td align="center">file</td></tr>
    <tr><td align="center">1</td>
        <td align="center">0</td>
        <td align="center">file</td></tr>
    <tr><td align="center">1</td>
        <td align="center">1</td>
        <td align="center">file</td></tr>
    <tr><td align="center">1</td>
        <td align="center">2</td>
        <td align="center">memory</td></tr>
    <tr><td align="center">2</td>
        <td align="center">0</td>
        <td align="center">memory</td></tr>
    <tr><td align="center">2</td>
        <td align="center">1</td>
        <td align="center">file</td></tr>
    <tr><td align="center">2</td>
        <td align="center">2</td>
        <td align="center">memory</td></tr>
    <tr><td align="center">3</td>
        <td align="center"><em>any</em></td>
        <td align="center">memory</td></tr>
    </table>
    </blockquote>
    </li>
    <br>

<a name="pragma_temp_store_directory"></a>
<li><p><b>PRAGMA temp_store_directory;
       <br>PRAGMA temp_store_directory = 'directory-name';</b></p>
    <p>Query or change the setting of the "temp_store_directory" - the
    directory where files used for storing temporary tables and indices
    are kept.  This setting lasts for the duration of the current connection
    only and resets to its default value for each new connection opened.







    <p>When the temp_store_directory setting is changed, all existing temporary
    tables, indices, triggers, and viewers are immediately deleted.  In
    practice, temp_store_directory should be set immediately after the 
    database is opened.  </p>

    <p>The value <i>directory-name</i> should be enclosed in single quotes.
    To revert the directory to the default, set the <i>directory-name</i> to
    an empty string, e.g., <i>PRAGMA temp_store_directory = ''</i>.  An
    error is raised if <i>directory-name</i> is not found or is not
    writable. </p>

    <p>The default directory for temporary files depends on the OS.  For
    Unix/Linux/OSX, the default is the is the first writable directory found
    in the list of: <b>/var/tmp, /usr/tmp, /tmp,</b> and <b>
    <i>current-directory</i></b>.  For Windows NT, the default
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<a name="pragma_vdbe_trace"></a>
<li><p><b>PRAGMA vdbe_trace = ON; </b>(1)<b>
    <br>PRAGMA vdbe_trace = OFF;</b> (0)</p>
    <p>Turn tracing of the virtual database engine inside of the
    SQLite library on and off.  This is used for debugging.  See the 
    <a href="vdbe.html#trace">VDBE documentation</a> for more 
    information.</p></li>












</ul>

}








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<a name="pragma_vdbe_trace"></a>
<li><p><b>PRAGMA vdbe_trace = ON; </b>(1)<b>
    <br>PRAGMA vdbe_trace = OFF;</b> (0)</p>
    <p>Turn tracing of the virtual database engine inside of the
    SQLite library on and off.  This is used for debugging.  See the 
    <a href="vdbe.html#trace">VDBE documentation</a> for more 
    information.</p></li>

<a name="pragma_vdbe_listing"></a>
<li><p><b>PRAGMA vdbe_listing = ON; </b>(1)<b>
    <br>PRAGMA vdbe_listing = OFF;</b> (0)</p>
    <p>Turn listings of virtual machine programs on and off.
    With listing is on, the entire content of a program is printed
    just prior to beginning execution.  This is like automatically
    executing an EXPLAIN prior to each statement.  The statement
    executes normally after the listing is printed.
    This is used for debugging.  See the 
    <a href="vdbe.html#trace">VDBE documentation</a> for more 
    information.</p></li>
</ul>

}