1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html><head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>SQLite Query Language: ATTACH DATABASE</title>
<style type="text/css">
body {
margin: auto;
font-family: Verdana, sans-serif;
padding: 8px 1%;
}
a { color: #044a64 }
a:visited { color: #734559 }
.logo { position:absolute; margin:3px; }
.tagline {
float:right;
text-align:right;
font-style:italic;
width:300px;
margin:12px;
margin-top:58px;
}
.toolbar {
text-align: center;
line-height: 1.6em;
margin: 0;
padding: 0px 8px;
}
.toolbar a { color: white; text-decoration: none; padding: 6px 12px; }
.toolbar a:visited { color: white; }
.toolbar a:hover { color: #044a64; 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.gif) 100% 100% no-repeat #044a64}
.sw { background: url(images/sw.gif) 0% 100% no-repeat }
.ne { background: url(images/ne.gif) 100% 0% no-repeat }
.nw { background: url(images/nw.gif) 0% 0% no-repeat }
/* Things for "fancyformat" documents start here. */
.fancy img+p {font-style:italic}
.fancy .codeblock i { color: darkblue; }
.fancy h1,.fancy h2,.fancy h3,.fancy h4 {font-weight:normal;color:#044a64}
.fancy h2 { margin-left: 10px }
.fancy h3 { margin-left: 20px }
.fancy h4 { margin-left: 30px }
.fancy th {white-space:nowrap;text-align:left;border-bottom:solid 1px #444}
.fancy th, .fancy td {padding: 0.2em 1ex; vertical-align:top}
.fancy #toc a { color: darkblue ; text-decoration: none }
.fancy .todo { color: #AA3333 ; font-style : italic }
.fancy .todo:before { content: 'TODO:' }
.fancy p.todo { border: solid #AA3333 1px; padding: 1ex }
.fancy img { display:block; }
.fancy :link:hover, .fancy :visited:hover { background: wheat }
.fancy p,.fancy ul,.fancy ol { margin: 1em 5ex }
.fancy li p { margin: 1em 0 }
/* End of "fancyformat" specific rules. */
</style>
</head>
<body>
<div><!-- container div to satisfy validator -->
<a href="index.html">
<img class="logo" src="images/sqlite370_banner.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">
<table width=100% style="padding:0;margin:0;cell-spacing:0"><tr>
<td width=100%>
<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="support.html">Support</a>
</div>
<script>
gMsg = "Search SQLite Docs..."
function entersearch() {
var q = document.getElementById("q");
if( q.value == gMsg ) { q.value = "" }
q.style.color = "black"
q.style.fontStyle = "normal"
}
function leavesearch() {
var q = document.getElementById("q");
if( q.value == "" ) {
q.value = gMsg
q.style.color = "#044a64"
q.style.fontStyle = "italic"
}
}
</script>
<td>
<div style="padding:0 1em 0px 0;white-space:nowrap">
<form name=f method="GET" action="http://www.sqlite.org/search">
<input id=q name=q type=text
onfocus="entersearch()" onblur="leavesearch()" style="width:24ex;padding:1px 1ex; border:solid white 1px; font-size:0.9em ; font-style:italic;color:#044a64;" value="Search SQLite Docs...">
<input type=submit value="Go" style="border:solid white 1px;background-color:#044a64;color:white;font-size:0.9em;padding:0 1ex">
</form>
</div>
</table>
</div></div></div></div>
</td></tr></table>
<div class=startsearch></div>
<h1 align="center">SQL As Understood By SQLite</h1><p><a href="lang.html">[Top]</a></p><h2>ATTACH DATABASE</h2><h4><a href="syntaxdiagrams.html#attach-stmt">attach-stmt:</a></h4><blockquote> <img alt="syntax diagram attach-stmt" src="images/syntax/attach-stmt.gif"></img> </blockquote>
<p> The ATTACH DATABASE statement adds another database
file to the current <a href="c3ref/sqlite3.html">database connection</a>.
The filename for the database to be attached is the value of
the expression that occurs before the AS keyword.
The filename of the database follows the same semantics as the
filename argument to <a href="c3ref/open.html">sqlite3_open()</a> and <a href="c3ref/open.html">sqlite3_open_v2()</a>; the
special name "<a href="inmemorydb.html">:memory:</a>" results in an <a href="inmemorydb.html">in-memory database</a> and an
empty string results in a new temporary database.
The filename argument can be a <a href="uri.html">URI filename</a> if URI filename processing
is enable on the database connection. The default behavior is for
URI filenames to be disabled, however that might change in a future release
of SQLite, so application developers are advised to plan accordingly.
<p>The name that occurs after the AS keyword is the name of the database
used internally by SQLite.
The database-names 'main' and
'temp' refer to the main database and the database used for
temporary tables. The main and temp databases cannot be attached or
detached.</p>
<p> Tables in an attached database can be referred to using the syntax
<i>database-name.table-name</i>. If the name of the table is unique
across all attached databases and the main and temp databases, then the
<i>database-name</i> prefix is not required. If two or more tables in
different databases have the same name and the
<i>database-name</i> prefix is not used on a table reference, then the
table chosen is the one in the database that was least recently attached.</p>
<p>
Transactions involving multiple attached databases are atomic,
assuming that the main database is not "<a href="inmemorydb.html">:memory:</a>" and the
<a href="pragma.html#pragma_journal_mode">journal_mode</a> is not <a href="wal.html">WAL</a>. If the main
database is ":memory:" or if the journal_mode is WAL, then
transactions continue to be atomic within each individual
database file. But if the host computer crashes in the middle
of a <a href="lang_transaction.html">COMMIT</a> where two or more database files are updated,
some of those files might get the changes where others
might not.
</p>
<p> There is a limit, set using <a href="c3ref/limit.html">sqlite3_limit()</a> and
<a href="c3ref/c_limit_attached.html#sqlitelimitattached">SQLITE_LIMIT_ATTACHED</a>, to the number of databases that can be
simultaneously attached to a single database connection.</p>
|
