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Overview
| Comment: | Document the goofy behavior of PRIMARY KEY(x DESC) still allowing x to be a rowid if it is of type INTEGER. |
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| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | b354d151517608bf7101f874c9b43e05 |
| User & Date: | drh 2009-05-11 17:41:10 |
Context
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2009-05-14
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| 18:12 | Changed lang.html to use hd_resolve for linkage rather than crafted links. check-in: 17a3eefb66 user: shaneh tags: trunk | |
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2009-05-11
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| 17:41 | Document the goofy behavior of PRIMARY KEY(x DESC) still allowing x to be a rowid if it is of type INTEGER. check-in: b354d15151 user: drh tags: trunk | |
| 14:24 | Fixed typo. check-in: 218a28e1d5 user: shaneh tags: trunk | |
Changes
Changes to pages/lang.in.
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The AUTOINCREMENT keyword only works on a column that is an alias
for the rowid.</p>
<p>Note that searches against a rowid are generally about twice as
fast as searches against any other PRIMARY KEY or indexed value.
</p>
<tcl>
##############################################################################
Section {CREATE TRIGGER} createtrigger {{CREATE TRIGGER}}
BubbleDiagram create-trigger-stmt 1
</tcl>
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The AUTOINCREMENT keyword only works on a column that is an alias for the rowid.</p> <p>Note that searches against a rowid are generally about twice as fast as searches against any other PRIMARY KEY or indexed value. </p> <p><b>Goofy behavior alert:</b> The following three declarations all cause the column "x" be an alias for the rowid:</p> <ul> <li><tt>CREATE TABLE t(x INTEGER PRIMARY KEY ASC, y, z);</tt> <li><tt>CREATE TABLE t(x INTEGER, y, z, PRIMARY KEY(x ASC));</tt> <li><tt>CREATE TABLE t(x INTEGER, y, z, PRIMARY KEY(x DESC));</tt> </ul> <p>But, in contrast, the following declaration does <u>not</u> result in "x" being an alias for the rowid:</p> <ul> <li><tt>CREATE TABLE t(x INTEGER PRIMARY KEY DESC, y, z);</tt> </ul> <p>This asymmetrical behavior is unfortunate and is really due to a bug in the parser in early versions of SQLite. But fixing the bug would result in very serious backwards incompatibilities. The SQLite developers feel that goofy behavior in an corner case is far better than a compatibility break, so the original behavior is retained.</p> <tcl> ############################################################################## Section {CREATE TRIGGER} createtrigger {{CREATE TRIGGER}} BubbleDiagram create-trigger-stmt 1 </tcl> |