Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
| Comment: | Documented integer values used by PRAGMAs. Fixed missing end tags in generated anchors. (CVS 1022) |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
6c24dfbae56a16dd736de5297c179681 |
| User & Date: | jplyon 2003-06-15 10:29:25.000 |
Context
|
2003-06-15
| ||
| 10:35 | Updated sqlite_encode_binary() comments with tighter bounds on output length. (CVS 1023) (check-in: 826aab43d5 user: jplyon tags: trunk) | |
| 10:29 | Documented integer values used by PRAGMAs. Fixed missing end tags in generated anchors. (CVS 1022) (check-in: 6c24dfbae5 user: jplyon tags: trunk) | |
|
2003-06-14
| ||
| 19:29 | * Added -version-info to shared libraries * Remove config.h and libtool in the distclean target (CVS 1021) (check-in: e13e8b05b4 user: a.rottmann tags: trunk) | |
Changes
Changes to www/lang.tcl.
1 2 3 | # # Run this Tcl script to generate the sqlite.html file. # | | | 1 2 3 4 5 6 7 8 9 10 11 |
#
# Run this Tcl script to generate the sqlite.html file.
#
set rcsid {$Id: lang.tcl,v 1.62 2003/06/15 10:29:25 jplyon Exp $}
puts {<html>
<head>
<title>Query Language Understood By SQLite</title>
</head>
<body bgcolor=white>
<h1 align=center>
|
| ︙ | ︙ | |||
109 110 111 112 113 114 115 |
return "<font color=\"#2c2cf0\">$name</font>"
}
proc Section {name {label {}}} {
puts "\n<hr />"
if {$label!=""} {
| | | 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 |
return "<font color=\"#2c2cf0\">$name</font>"
}
proc Section {name {label {}}} {
puts "\n<hr />"
if {$label!=""} {
puts "<a name=\"$label\"></a>"
}
puts "<h1>$name</h1>\n"
}
proc Example {text} {
puts "<blockquote><pre>$text</pre></blockquote>"
}
|
| ︙ | ︙ | |||
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 |
}
puts {
<p>The PRAGMA command is used to modify the operation of the SQLite library.
The pragma command is experimental and specific pragma statements may be
removed or added in future releases of SQLite. Use this command
with caution.</p>
<p>The current implementation supports the following pragmas:</p>
<ul>
<a name="pragma_cache_size"></a>
<li><p><b>PRAGMA cache_size;
<br>PRAGMA cache_size = </b><i>Number-of-pages</i><b>;</b></p>
<p>Query or change the maximum number of database disk pages that SQLite
will hold in memory at once. Each page uses about 1.5K of memory.
The default cache size is 2000. If you are doing UPDATEs or DELETEs
that change many rows of a database and you do not mind if SQLite
uses more memory, you can increase the cache size for a possible speed
improvement.</p>
<p>When you change the cache size using the cache_size pragma, the
change only endures for the current session. The cache size reverts
to the default value when the database is closed and reopened. Use
the <a href="#pragma_default_cache_size"><b>default_cache_size</b></a>
pragma to check the cache size permanently.</p></li>
| > > > > > > > > | | | | | | > | | | | | | | | | | | | | | 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 |
}
puts {
<p>The PRAGMA command is used to modify the operation of the SQLite library.
The pragma command is experimental and specific pragma statements may be
removed or added in future releases of SQLite. Use this command
with caution.</p>
<p>The pragmas that take an integer <b><i>value</i></b> also accept
symbolic names. The strings "<b>on</b>", "<b>true</b>", and "<b>yes</b>"
are equivalent to <b>1</b>. The strings "<b>off</b>", "<b>false</b>",
and "<b>no</b>" are equivalent to <b>0</b>. These strings are case-
insensitive, and do not require quotes. An unrecognized string will be
treated as <b>1</b>, and will not generate an error. When the <i>value</i>
is returned it is as an integer.</p>
<p>The current implementation supports the following pragmas:</p>
<ul>
<a name="pragma_cache_size"></a>
<li><p><b>PRAGMA cache_size;
<br>PRAGMA cache_size = </b><i>Number-of-pages</i><b>;</b></p>
<p>Query or change the maximum number of database disk pages that SQLite
will hold in memory at once. Each page uses about 1.5K of memory.
The default cache size is 2000. If you are doing UPDATEs or DELETEs
that change many rows of a database and you do not mind if SQLite
uses more memory, you can increase the cache size for a possible speed
improvement.</p>
<p>When you change the cache size using the cache_size pragma, the
change only endures for the current session. The cache size reverts
to the default value when the database is closed and reopened. Use
the <a href="#pragma_default_cache_size"><b>default_cache_size</b></a>
pragma to check the cache size permanently.</p></li>
<li><p><b>PRAGMA count_changes = ON; </b>(1)<b>
<br>PRAGMA count_changes = OFF;</b> (0)</p>
<p>When on, the COUNT_CHANGES pragma causes the callback function to
be invoked once for each DELETE, INSERT, or UPDATE operation. The
argument is the number of rows that were changed.</p>
<p>This pragma may be removed from future versions of SQLite.
Consider using the <b>sqlite_changes()</b> API function instead.</p></li>
<li><p><b>PRAGMA database_list;</b></p>
<p>For each open database, invoke the callback function once with
information about that database. Arguments include the index and
the name the datbase was attached with. The first row will be for
the main database. The second row will be for the database used to
store temporary tables.</p></li>
<a name="pragma_default_cache_size"></a>
<li><p><b>PRAGMA default_cache_size;
<br>PRAGMA default_cache_size = </b><i>Number-of-pages</i><b>;</b></p>
<p>Query or change the maximum number of database disk pages that SQLite
will hold in memory at once. Each page uses 1K on disk and about 1.5K in memory.
This pragma works like the <a href="#pragma_cache_size"><b>cache_size</b></a>
pragma with the additional
feature that it changes the cache size persistently. With this pragma,
you can set the cache size once and that setting is retained and reused
everytime you reopen the database.</p></li>
<a name="pragma_default_synchronous"></a>
<li><p><b>PRAGMA default_synchronous;
<br>PRAGMA default_synchronous = FULL; </b>(2)<b>
<br>PRAGMA default_synchronous = NORMAL; </b>(1)<b>
<br>PRAGMA default_synchronous = OFF; </b>(0)</p>
<p>Query or change the setting of the "synchronous" flag in
the database. The first (query) form will return the setting as an
integer. When synchronous is FULL (2), the SQLite database engine will
pause at critical moments to make sure that data has actually been
written to the disk surface before continuing. This ensures that if
the operating system crashes or if there is a power failure, the database
will be uncorrupted after rebooting. FULL synchronous is very
safe, but it is also slow.
When synchronous is NORMAL (1, the default), the SQLite database
engine will still pause at the most critical moments, but less often
than in FULL mode. There is a very small (though non-zero) chance that
a power failure at just the wrong time could corrupt the database in
NORMAL mode. But in practice, you are more likely to suffer
a catastrophic disk failure or some other unrecoverable hardware
fault. So NORMAL is the default mode.
With synchronous OFF (0), SQLite continues without pausing
as soon as it has handed data off to the operating system.
If the application running SQLite crashes, the data will be safe, but
the database might become corrupted if the operating system
crashes or the computer loses power before that data has been written
to the disk surface. On the other hand, some
operations are as much as 50 or more times faster with synchronous OFF.
</p>
<p>This pragma changes the synchronous mode persistently. Once changed,
the mode stays as set even if the database is closed and reopened. The
<a href="#pragma_synchronous"><b>synchronous</b></a> pragma does the same
thing but only applies the setting to the current session.</p></li>
<a name="pragma_default_temp_store"></a>
<li><p><b>PRAGMA default_temp_store;
<br>PRAGMA default_temp_store = DEFAULT; </b>(0)<b>
<br>PRAGMA default_temp_store = MEMORY; </b>(2)<b>
<br>PRAGMA default_temp_store = FILE;</b> (1)</p>
<p>Query or change the setting of the "temp_store" flag stored in
the database. When temp_store is DEFAULT (0), the compile-time default
is used for the temporary database. When temp_store is MEMORY (2), an
in-memory database is used. When temp_store is FILE (1), a temporary
database file on disk will be used. Note that it is possible for
the library compile-time options to override this setting. Once
the temporary database is in use, its location cannot be changed.</p>
<p>This pragma changes the temp_store mode persistently. Once changed,
the mode stays as set even if the database is closed and reopened. The
<a href="#pragma_temp_store"><b>temp_store</b></a> pragma does the same
thing but only applies the setting to the current session.</p></li>
<a name="pragma_empty_result_callbacks"></a>
<li><p><b>PRAGMA empty_result_callbacks = ON; </b>(1)<b>
<br>PRAGMA empty_result_callbacks = OFF;</b> (0)</p>
<p>When on, the EMPTY_RESULT_CALLBACKS pragma causes the callback
function to be invoked once for each query that has an empty result
set. The third "<b>argv</b>" parameter to the callback is set to NULL
because there is no data to report. But the second "<b>argc</b>" and
fourth "<b>columnNames</b>" parameters are valid and can be used to
determine the number and names of the columns that would have been in
the result set had the set not been empty.</p></li>
<li><p><b>PRAGMA full_column_names = ON; </b>(1)<b>
<br>PRAGMA full_column_names = OFF;</b> (0)</p>
<p>The column names reported in an SQLite callback are normally just
the name of the column itself, except for joins when "TABLE.COLUMN"
is used. But when full_column_names is turned on, column names are
always reported as "TABLE.COLUMN" even for simple queries.</p></li>
<li><p><b>PRAGMA index_info(</b><i>index-name</i><b>);</b></p>
<p>For each column that the named index references, invoke the
|
| ︙ | ︙ | |||
1355 1356 1357 1358 1359 1360 1361 |
<li><p><b>PRAGMA integrity_check;</b></p>
<p>The command does an integrity check of the entire database. It
looks for out-of-order records, missing pages, and malformed records.
If any problems are found, then a single string is returned which is
a description of all problems. If everything is in order, "ok" is
returned.</p></li>
| | > | > | 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 |
<li><p><b>PRAGMA integrity_check;</b></p>
<p>The command does an integrity check of the entire database. It
looks for out-of-order records, missing pages, and malformed records.
If any problems are found, then a single string is returned which is
a description of all problems. If everything is in order, "ok" is
returned.</p></li>
<li><p><b>PRAGMA parser_trace = ON; </b>(1)<b>
<br>PRAGMA parser_trace = OFF;</b> (0)</p>
<p>Turn tracing of the SQL parser inside of the
SQLite library on and off. This is used for debugging.
This only works if the library is compiled without the NDEBUG macro.
</p></li>
<a name="pragma_show_datatypes"></a>
<li><p><b>PRAGMA show_datatypes = ON; </b>(1)<b>
<br>PRAGMA show_datatypes = OFF;</b> (0)</p>
<p>When turned on, the SHOW_DATATYPES pragma causes extra entries containing
the names of <a href="datatypes.html">datatypes</a> of columns to be
appended to the 4th ("columnNames") argument to <b>sqlite_exec()</b>
callbacks. When
turned off, the 4th argument to callbacks contains only the column names.
The datatype for table columns is taken from the CREATE TABLE statement
that defines the table. Columns with an unspecified datatype have a
|
| ︙ | ︙ | |||
1395 1396 1397 1398 1399 1400 1401 |
azCol[4] = "NUMERIC";<br>
azCol[5] = "TEXT";<br>
azCol[6] = 0;
</td></table></blockquote></li>
<a name="pragma_synchronous"></a>
<li><p><b>PRAGMA synchronous;
| | | | | | | | > | 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 |
azCol[4] = "NUMERIC";<br>
azCol[5] = "TEXT";<br>
azCol[6] = 0;
</td></table></blockquote></li>
<a name="pragma_synchronous"></a>
<li><p><b>PRAGMA synchronous;
<br>PRAGMA synchronous = FULL; </b>(2)<b>
<br>PRAGMA synchronous = NORMAL; </b>(1)<b>
<br>PRAGMA synchronous = OFF;</b> (0)</p>
<p>Query or change the setting of the "synchronous" flag affecting
the database for the duration of the current database connection.
The synchronous flag reverts to its default value when the database
is closed and reopened. For additional information on the synchronous
flag, see the description of the <a href="#pragma_default_synchronous">
<b>default_synchronous</b></a> pragma.</p>
</li>
<li><p><b>PRAGMA table_info(</b><i>table-name</i><b>);</b></p>
<p>For each column in the named table, invoke the callback function
once with information about that column, including the column name,
data type, whether or not the column can be NULL, and the default
value for the column.</p></li>
<a name="pragma_temp_store"></a>
<li><p><b>PRAGMA temp_store;
<br>PRAGMA temp_store = DEFAULT; </b>(0)<b>
<br>PRAGMA temp_store = MEMORY; </b>(2)<b>
<br>PRAGMA temp_store = FILE;</b> (1)</p>
<p>Query or change the setting of the "temp_store" flag affecting
the database for the duration of the current database connection.
The temp_store flag reverts to its default value when the database
is closed and reopened. For additional information on the temp_store
flag, see the description of the <a href="#pragma_default_temp_store">
<b>default_temp_store</b></a> pragma. Note that it is possible for
the library compile-time options to override this setting. </p>
</li>
<a name="pragma_vdbe_trace"></a>
<li><p><b>PRAGMA vdbe_trace = ON; </b>(1)<b>
<br>PRAGMA vdbe_trace = OFF;</b> (0)</p>
<p>Turn tracing of the virtual database engine inside of the
SQLite library on and off. This is used for debugging. See the
<a href="vdbe.html#trace">VDBE documentation</a> for more
information.</p></li>
</ul>
<p>No error message is generated if an unknown pragma is issued.
|
| ︙ | ︙ |