99 lines
3.1 KiB
Tcl
99 lines
3.1 KiB
Tcl
#
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# Run this script to generated a omitted.html output file
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#
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set rcsid {$Id: omitted.tcl,v 1.6 2004/05/31 15:06:30 drh Exp $}
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source common.tcl
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header {SQL Features That SQLite Does Not Implement}
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puts {
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<h2>SQL Features That SQLite Does Not Implement</h2>
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<p>
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Rather than try to list all the features of SQL92 that SQLite does
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support, it is much easier to list those that it does not.
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Unsupported features of SQL92 are shown below.</p>
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<p>
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The order of this list gives some hint as to when a feature might
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be added to SQLite. Those features near the top of the list are
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likely to be added in the near future. There are no immediate
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plans to add features near the bottom of the list.
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</p>
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<table cellpadding="10">
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}
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proc feature {name desc} {
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puts "<tr><td valign=\"top\"><b><nobr>$name</nobr></b></td>"
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puts "<td width=\"10\"> </th>"
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puts "<td valign=\"top\">$desc</td></tr>"
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}
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feature {CHECK constraints} {
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CHECK constraints are parsed but they are not enforced.
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NOT NULL and UNIQUE constraints are enforced, however.
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}
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feature {Variable subqueries} {
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Subqueries must be static. They are evaluated only once. They may not,
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therefore, refer to variables in the main query.
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}
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feature {FOREIGN KEY constraints} {
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FOREIGN KEY constraints are parsed but are not enforced.
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}
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feature {Complete trigger support} {
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There is some support for triggers but it is not complete. Missing
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subfeatures include FOR EACH STATEMENT triggers (currently all triggers
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must be FOR EACH ROW), INSTEAD OF triggers on tables (currently
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INSTEAD OF triggers are only allowed on views), and recursive
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triggers - triggers that trigger themselves.
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}
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feature {ALTER TABLE} {
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To change a table you have to delete it (saving its contents to a temporary
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table) and recreate it from scratch.
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}
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feature {Nested transactions} {
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The current implementation only allows a single active transaction.
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}
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feature {The COUNT(DISTINCT X) function} {
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You can accomplish the same thing using a subquery, like this:<br />
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SELECT count(x) FROM (SELECT DISTINCT x FROM tbl);
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}
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feature {RIGHT and FULL OUTER JOIN} {
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LEFT OUTER JOIN is implemented, but not RIGHT OUTER JOIN or
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FULL OUTER JOIN.
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}
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feature {Writing to VIEWs} {
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VIEWs in SQLite are read-only. You may not execute a DELETE, INSERT, or
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UPDATE statement on a view. But you can create a trigger
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that fires on an attempt to DELETE, INSERT, or UPDATE a view and do
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what you need in the body of the trigger.
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}
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feature {GRANT and REVOKE} {
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Since SQLite reads and writes an ordinary disk file, the
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only access permissions that can be applied are the normal
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file access permissions of the underlying operating system.
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The GRANT and REVOKE commands commonly found on client/server
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RDBMSes are not implemented because they would be meaningless
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for an embedded database engine.
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}
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puts {
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</table>
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<p>
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If you find other SQL92 features that SQLite does not support, please
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add them to the Wiki page at
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<a href="http://www.sqlite.org/cvstrac/wiki?p=UnsupportedSql">
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http://www.sqlite.org/cvstrac/wiki?p=Unsupported</a>
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</p>
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}
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footer $rcsid
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