Documentation Source Text

<dt><b>-readonly</b> <i>BOOLEAN</i></dt>
<dd><p>
If true, then open the database file read-only.  If false, then the
database is opened for both reading and writing if filesystem permissions
allow, or for reading only if filesystem write permission is denied
by the operating system.  The default setting is "false".  Note that
if the previous process to have the database did not exits cleanly
and left behind a [hot journal], then the write permission is required
to recover the database after opening, and the database cannot be
opened read-only.
</p></dd>

<dt><b>-uri</b> <i>BOOLEAN</i></dt>
<dd><p>
If true, then interpret the filename argument as a [URI filename].  If
false, then the argument is a literal filename.  The default value is
"false".
</p></dd>

<dt><b>-vfs</b> <i>VFSNAME</i></dt>
<dd><p>
Use an alternative [VFS] named by the argument.
</p></dd>

</dl>
</blockquote>

<p>
Once an SQLite database is open, it can be controlled using 
methods of the <i>dbcmd</i>.  There are currently 22 methods
defined.</p>

<p>
<ul>

<tcl>
foreach m [lsort {
 authorizer
 backup
 busy
 cache
 changes
 close
 collate

 total_changes
 trace
 transaction
 unlock_notify
 update_hook
 version
 wal_hook
}] {





















 hd_puts "<li><a href=\"#$m\">$m</a></li>"
}
</tcl>
</ul>
</p>


<p>The use of each of these methods will be explained in the sequel, though
not in the order shown above.</p>

<tcl>
##############################################################################
METHOD eval {
<p>
The most useful <i>dbcmd</i> method is "eval".  The eval method is used
to execute SQL on the database.  The syntax of the eval method looks
like this:</p>

<blockquote>
<i>dbcmd</i>&nbsp;&nbsp;<b>eval</b>&nbsp;&nbsp;<i>sql</i>
&nbsp;&nbsp;&nbsp;&nbsp;?<i>array-name&nbsp;</i>?&nbsp;?<i>script</i>?
</blockquote>

<p>
The job of the eval method is to execute the SQL statement or statements
given in the second argument.  For example, to create a new table in
a database, you can do this:</p>

</p>

<p>
If the $bigstring variable has both a string and a "bytearray" representation,
then TCL inserts the value as a string.  If it has only a "bytearray"
representation, then the value is inserted as a BLOB.  To force a
value to be inserted as a BLOB even if it also has a text representation,
us a "@" character to in place of the "$".  Like this:
</p>

<blockquote><b>
db1 eval {INSERT INTO t1 VALUES(5,@bigstring)}
</b></blockquote>

<p>

<p>
The syntax looks like this:
</p>

<blockquote>
<i>dbcmd</i>&nbsp;&nbsp;<b>transaction</b>&nbsp;&nbsp;<i>?transaction-type?</i>
&nbsp;&nbsp;<i>SCRIPT,</i>
</blockquote>


<p>
The <i>transaction-type</i> can be one of <b>deferred</b>,
<b>exclusive</b> or <b>immediate</b>.  The default is deferred.
</p>

The "copy" method copies data from a file into a table.
It returns the number of rows processed successfully from the file.
The syntax of the copy method looks like this:</p>

<blockquote>
<i>dbcmd</i>&nbsp;&nbsp;<b>copy</b>&nbsp;&nbsp;<i>conflict-algorithm</i>
&nbsp;&nbsp;<i>table-name&nbsp;</i>&nbsp;&nbsp;<i>file-name&nbsp;</i>
&nbsp;&nbsp;&nbsp;&nbsp;?<i>column-separator&nbsp;</i>?
&nbsp;&nbsp;?<i>null-indicator</i>?
</blockquote>

<p>Conflict-algorithm must be one of the SQLite conflict algorithms for
the INSERT statement: <i>rollback</i>, <i>abort</i>,
<i>fail</i>,<i>ignore</i>, or <i>replace</i>. See the SQLite Language
section for <a href="lang.html#conflict">ON CONFLICT</a> for more information.

The default is an empty string.  Note that column-separator and
null-indicator are optional positional arguments; if null-indicator
is specified, a column-separator argument must be specified and
precede the null-indicator argument.</p>

<p>The copy method implements similar functionality to the <b>.import</b>
SQLite shell command. 
The SQLite 2.x <a href="lang.html#copy"><b>COPY</b></a> statement 
(using the PostgreSQL COPY file format)
can be implemented with this method as:</p>

<blockquote>
dbcmd&nbsp;&nbsp;copy&nbsp;&nbsp;$conflictalgo
&nbsp;&nbsp;$tablename&nbsp;&nbsp;&nbsp;$filename&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;\t&nbsp;
&nbsp;&nbsp;\\N
</blockquote>

}

##############################################################################
METHOD timeout {

<p>The "timeout" method is used to control how long the SQLite library
will wait for locks to clear before giving up on a database transaction.

##############################################################################
METHOD incrblob {

<p>This method opens a TCL channel that can be used to read or write
into a preexisting BLOB in the database.  The syntax is like this:</p>

<blockquote>
<i>dbcmd</i>&nbsp;&nbsp;<b>incrblob</b>&nbsp;&nbsp;<b>?-readonly??</b>
&nbsp;&nbsp;<i>?DB?&nbsp;&nbsp;TABLE&nbsp;&nbsp;COLUMN&nbsp;&nbsp;ROWID</i>
</blockquote>

<p>
The command returns a new TCL channel for reading or writing to the BLOB.
The channel is opened using the underlying 
<a href="c3ref/blob_open.html">sqlite3_blob_open()</a> C-language

written.  <i>Backup-filename</i> does not have to exist ahead of time, but if
it does, it must be a well-formed SQLite database.</p>
}

##############################################################################
METHOD restore {

<p>The "restore" method copies the content a separate database file 
into the current database connection, overwriting any preexisting content.
The command syntax is like this:</p>

<blockquote>
<i>dbcmd</i>&nbsp;&nbsp;<b>restore</b>&nbsp;&nbsp;?<i>target-database</i>?&nbsp;&nbsp;<i>source-filename</i>
</blockquote>