📄 lang_altertable.html

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>SQLite Query Language: ALTER TABLE</title><style type="text/css">body {    margin: auto;    font-family: "Verdana" "sans-serif";    padding: 8px 1%;}a { color: #45735f }a:visited { color: #734559 }.logo { position:absolute; margin:3px; }.tagline {  float:right;  text-align:right;  font-style:italic;  width:240px;  margin:12px;  margin-top:58px;}.toolbar {  font-variant: small-caps;  text-align: center;  line-height: 1.6em;  margin: 0;  padding:1px 8px;}.toolbar a { color: white; text-decoration: none; padding: 6px 12px; }.toolbar a:visited { color: white; }.toolbar a:hover { color: #80a796; background: white; }.content    { margin: 5%; }.content dt { font-weight:bold; }.content dd { margin-bottom: 25px; margin-left:20%; }.content ul { padding:0px; padding-left: 15px; margin:0px; }/* rounded corners */.se  { background: url(images/se.png) 100% 100% no-repeat #80a796}.sw  { background: url(images/sw.png) 0% 100% no-repeat }.ne  { background: url(images/ne.png) 100% 0% no-repeat }.nw  { background: url(images/nw.png) 0% 0% no-repeat }</style><meta http-equiv="content-type" content="text/html; charset=UTF-8">  </head><body><div><!-- container div to satisfy validator --><a href="index.html"><img class="logo" src="images/SQLite.gif" alt="SQLite Logo" border="0"></a><div><!-- IE hack to prevent disappearing logo--></div><div class="tagline">Small. Fast. Reliable.<br>Choose any three.</div><table width=100% style="clear:both"><tr><td>  <div class="se"><div class="sw"><div class="ne"><div class="nw">  <div class="toolbar">    <a href="about.html">About</a>    <a href="sitemap.html">Sitemap</a>    <a href="docs.html">Documentation</a>    <a href="download.html">Download</a>    <a href="copyright.html">License</a>    <a href="news.html">News</a>    <a href="http://www.sqlite.org/cvstrac/index">Developers</a>    <a href="support.html">Support</a>  </div></div></div></div></div></td></tr></table>  <a href="lang.html"><h2>SQL As Understood By SQLite</h2></a><h3>ALTER TABLE</h3><table cellpadding="10"><tr><td align="right" valign="top"><i><font color="#ff3434">sql-statement</font></i>&nbsp;::=</td><td><b><font color="#2c2cf0">ALTER TABLE </font></b>[<b><font color="#2c2cf0"></font></b><i><font color="#ff3434">database-name</font></i><b><font color="#2c2cf0"> <big>.</big></font></b>]<b><font color="#2c2cf0"> </font></b><i><font color="#ff3434">table-name</font></i><b><font color="#2c2cf0"> </font></b><i><font color="#ff3434">alteration</font></i><b><font color="#2c2cf0"></font></b></td></tr><tr><td align="right" valign="top"><i><font color="#ff3434">alteration</font></i>&nbsp;::=</td><td><b><font color="#2c2cf0">RENAME TO </font></b><i><font color="#ff3434">new-table-name</font></i><b><font color="#2c2cf0"></font></b></td></tr><tr><td align="right" valign="top"><i><font color="#ff3434">alteration</font></i>&nbsp;::=</td><td><b><font color="#2c2cf0">ADD </font></b>[<b><font color="#2c2cf0">COLUMN</font></b>]<b><font color="#2c2cf0"> </font></b><i><font color="#ff3434">column-def</font></i><b><font color="#2c2cf0"></font></b></td></tr></table><p>SQLite supports a limited subset of ALTER TABLE.The ALTER TABLE command in SQLite allows the user to rename a tableor to add a new column to an existing table. It is not possibleto rename a colum, remove a column, or add or remove constraints from a table.</p><p>The RENAME TO syntax is used to rename the table identified by <i>&#91;database-name.&#93;table-name</i> to <i>new-table-name</i>.This command cannot be used to move a table between attached databases, only to rename a table within the same database.</p><p>If the table being renamed has triggers or indices, then these remainattached to the table after it has been renamed. However, if there areany view definitions, or statements executed by triggers that refer tothe table being renamed, these are not automatically modified to use the newtable name. If this is required, the triggers or view definitions must bedropped and recreated to use the new table name by hand.</p><p>The ADD &#91;COLUMN&#93; syntaxis used to add a new column to an existing table.The new column is always appended to the end of the list of existing columns.<i>Column-def</i> may take any of the forms permissable in a <a href="lang_createtable.html">CREATE TABLE</a>statement, with the following restrictions:<ul><li>The column may not have a PRIMARY KEY or UNIQUE constraint.</li><li>The column may not have a default value of CURRENT_TIME, CURRENT_DATE     or CURRENT_TIMESTAMP.</li><li>If a NOT NULL constraint is specified, then the column must have a    default value other than NULL.</ul><p>The execution time of the ALTER TABLE command is independent ofthe amount of data in the table.  The ALTER TABLE command runs as quicklyon a table with 10 million rows as it does on a table with 1 row.</p><p>After ADD COLUMN has been run on a database, that database will notbe readable by SQLite version 3.1.3 and earlier.</p><hr><small><i>This page last modified 2008/04/27 17:48:52 UTC</i></small></div></body></html>
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