Documentation Source Text

set nChng 0
proc chng {date desc {options {}}} {
  global nChng aChng xrefChng
  set aChng($nChng) [list $date $desc $options]
  set xrefChng($date) $nChng
  incr nChng
}

chng {2019-02-00 (3.27.0)} {
<li>Added the [VACUUM INTO] command
<li>Issue an SQLITE_WARNING message on the [error log] if a 
[double-quoted string literal] is used.
}

chng {2018-12-01 (3.26.0)} {
<li>Optimization: When doing an [UPDATE] on a table with [indexes on expressions],
    do not update the expression indexes if they do not refer to any of the columns
    of the table being updated.
<li>Allow the [xBestIndex()] method of [virtual table] implementations to return
    [SQLITE_CONSTRAINT] to indicate that the proposed query plan is unusable and

#    ORDER BY mtime DESC;
#
# A small amount of manual editing and de-duplication followed.
#
# Manually edit the list for each subsequent release.
#      
foreach line [split {
xxxxxxxxxx|pending|Version 3.27.0
bf8c1b2b7a|2018-12-01|Version 3.26.0
89e099fbe5|2018-11-05|Version 3.25.3
fb90e7189a|2018-09-25|Version 3.25.2
2ac9003de4|2018-09-18|Version 3.25.1
b63af6c3bd|2018-09-15|Version 3.25.0
c7ee083322|2018-06-04|Version 3.24.0
4bb2294022|2018-04-10|Version 3.23.1

<title>SQLite Home Page</title>

<p>SQLite is a [self-contained], [high-reliability], 
[serverless|embedded],
[full-featured SQL|full-featured], [public-domain],
SQL database engine.
SQLite is the [most used] database engine in the world.
<a class="button" href="about.html">More Info</a></p>

<hr class="xhr">
<span class="hdrfont">Latest Release:&nbsp;&nbsp;</span>
<a href="releaselog/3_27_0.html">Version 3.27.0</a> ([dateof:3.27.0]).
<a class="button" href="download.html">Download</a>
<a class="button" href="chronology.html">Prior Releases</a>

<hr class="xhr">
<h3>Common Links</h3>
<tcl>common_links</tcl>

  <li> <p> When content is deleted from an SQLite database, the content is not
     usually erased but rather the space used to hold the content is marked as
     being available for reuse.  This can allow deleted content to be recovered
     by a hacker or by forensic analysis.  Running VACUUM will clean the database
     of all traces of deleted content, thus preventing an adversary from recovering
     deleted content.  Using VACUUM in this way is an alternative to setting
     [PRAGMA secure_delete=ON]. 

  <li> <p> ^Normally, the database [page_size] and whether or not the database
     supports [auto_vacuum] must be configured before the database file is
     actually created. ^However, when not in [write-ahead log] mode, the 
     [page_size] and/or [auto_vacuum] properties of an existing database may be
     changed by using the [page_size pragma|page_size]  and/or 
     [auto_vacuum|pragma auto_vacuum] pragmas and then immediately VACUUMing

</ol>
<p>
Full unicode case folding is supported in SQLite if it is compiled
with the [-DSQLITE_ENABLE_ICU] option and linked against the
[http://site.icu-project.org/|International Components for Unicode]
library.

<tcl>hd_fragment dblquote {double-quoted string literal}</tcl>
<h1>Double-quoted String Literals Are Accepted</h1>

<p>
The SQL standard says that one should use double-quotes around identifiers
and single-quotes around string literals.
<ul>
<li> <tt>"this is a legal SQL column name"</tt>

the SQL language to continue using double-quoted string literals when they
really need to learn to use the correct single-quoted string literal form.
<p>
In hindsight, we should not have tried to make SQLite accept MySQL 3.x
syntax, and should have never allowed double-quoted string literals.
However, we continue to support that capability to avoid breaking legacy
applications.
<p>
Update: As of SQLite 3.27.0 ([dateof:3.27.0]) the use of a double-quoted
string literal causes a warning message to be sent to the [error log].

<h1>Keywords Can Often Be Used As Identifiers</h1>

<p>
The SQL language is rich in keywords.
Most SQL implementations do not allow keywords to be used as identifiers
(the names of table or columns) unless they are enclosed in double-quotes.