Documentation Source Text

Check-in [06452075a4]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Add documentaion on the reverse_unordered_selects pragma.
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 06452075a4386737640d51baa75993f966329ace
User & Date: drh 2009-02-23 17:59:52
Context
2009-02-23
18:14
Added the beginnings of a change log for version 3.6.12. check-in: c926b561a2 user: drh tags: trunk
17:59
Add documentaion on the reverse_unordered_selects pragma. check-in: 06452075a4 user: drh tags: trunk
2009-02-22
16:52
Typo: change "what" to "want" in limits.html. check-in: 4c0e0cc065 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Show Whitespace Changes Patch

Changes to pages/pragma.in.

488
489
490
491
492
493
494





















495
496
497
498
499
500
501
    between connections that share a common page and schema cache.
    Cache sharing is enabled using the [sqlite3_enable_shared_cache()] API.
    Cache sharing is disabled by default.
    </p>

    <p>See [SQLite Shared-Cache Mode] for additional information.</p>
</li>






















<tcl>Subsection short_column_names</tcl>
<li><p><b>PRAGMA short_column_names;
       <br>PRAGMA short_column_names = </b><i>0 | 1</i><b>;</b></p>
    <p>Query or change the short-column-names flag. This flag affects
    the way SQLite names columns of data returned by [SELECT] statements
    when the expression for the column is a table-column name or the







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
    between connections that share a common page and schema cache.
    Cache sharing is enabled using the [sqlite3_enable_shared_cache()] API.
    Cache sharing is disabled by default.
    </p>

    <p>See [SQLite Shared-Cache Mode] for additional information.</p>
</li>

<tcl>Subsection reverse_unordered_selects</tcl>
<li><p><b>PRAGMA reverse_unordered_selects = </b><i>0 | 1</i><b>;</b></p>
    <p>When enabled, this PRAGMA causes [SELECT] statements without a
    an ORDER BY clause to emit their results in the reverse order of what
    they normally would.  This can help debug applications that are
    making invalid assumptions about the result order.<p>SQLite makes no
    guarantees about the order of results if a SELECT omits the ORDER BY
    clause.  Even so, the order of results does not change from one
    run to the next, and so many applications mistakenly come to depend
    on the arbitrary output order whatever that order happens to be.  However, 
    sometimes new versions of SQLite will contain optimizer enhancements
    that will cause the output order of queries without ORDER BY clauses
    to shift.  When that happens, applications that depend on a certain
    output order might malfunction.  By running the application multiple
    times with this pragma both disabled and enabled, cases where the
    application makes faulty assumptions about output order can be
    identified and fixed early, reducing problems
    that might be caused by linking against a different version of SQLite.
    </p>
</li>

<tcl>Subsection short_column_names</tcl>
<li><p><b>PRAGMA short_column_names;
       <br>PRAGMA short_column_names = </b><i>0 | 1</i><b>;</b></p>
    <p>Query or change the short-column-names flag. This flag affects
    the way SQLite names columns of data returned by [SELECT] statements
    when the expression for the column is a table-column name or the