Skip to content

H
h2database
切换分支/标签
查找文件
BlameHistoryPermalink
tutorial.html 55.0 KB
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 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 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 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 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!--
Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License, Version 1.0,
and under the Eclipse Public License, Version 1.0
(http://h2database.com/html/license.html).
Initial Developer: H2 Group
-->
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head><meta http-equiv="Content-Type" content="text/html;charset=utf-8" /><title>
Tutorial
</title><link rel="stylesheet" type="text/css" href="stylesheet.css" />
<!-- [search] { -->
<script type="text/javascript" src="navigation.js"></script>
</head><body onload="frameMe();">
<table class="content"><tr class="content"><td class="content"><div class="contentDiv">
<!-- } -->

<h1>Tutorial</h1>
<a href="#tutorial_starting_h2_console">
    Starting and Using the H2 Console</a><br />
<a href="#console_syntax">
    Special H2 Console Syntax</a><br />
<a href="#console_settings">
    Settings of the H2 Console</a><br />
<a href="#connecting_using_jdbc">
    Connecting to a Database using JDBC</a><br />
<a href="#creating_new_databases">
    Creating New Databases</a><br />
<a href="#using_server">
    Using the Server</a><br />
<a href="#using_hibernate">
    Using Hibernate</a><br />
<a href="#using_toplink">
    Using TopLink and Glassfish</a><br />
<a href="#using_eclipselink">
    Using EclipseLink</a><br />
<a href="#using_activemq">
    Using Apache ActiveMQ</a><br />
<a href="#using_netbeans">
    Using H2 within NetBeans</a><br />
<a href="#using_jooq">
    Using H2 with jOOQ</a><br />
<a href="#web_applications">
    Using Databases in Web Applications</a><br />
<a href="#android">
    Android</a><br />
<a href="#csv">
    CSV (Comma Separated Values) Support</a><br />
<a href="#upgrade_backup_restore">
    Upgrade, Backup, and Restore</a><br />
<a href="#command_line_tools">
    Command Line Tools</a><br />
<a href="#shell_tool">
    The Shell Tool</a><br />
<a href="#open_office">
    Using OpenOffice Base</a><br />
<a href="#web_start">
    Java Web Start / JNLP</a><br />
<a href="#connection_pool">
    Using a Connection Pool</a><br />
<a href="#fulltext">
    Fulltext Search</a><br />
<a href="#user_defined_variables">
    User-Defined Variables</a><br />
<a href="#date_time">
    Date and Time</a><br />
<a href="#spring">
    Using Spring</a><br />
<a href="#jmx">
    Java Management Extension (JMX)</a><br />

<h2 id="tutorial_starting_h2_console">Starting and Using the H2 Console</h2>
<p>
The H2 Console application lets you access a database using a browser.
This can be a H2 database, or another database that supports the JDBC API.
</p>
<img src="images/console.png" alt="Web Browser - H2 Console Server - H2 Database" />
<p>
This is a client/server application, so both a server and a client (a browser) are required to run it.
</p><p>
Depending on your platform and environment, there are multiple ways to start the H2 Console:
</p>
<table class="main">
<tr><th>OS</th><th>Start</th></tr>
<tr>
    <td>Windows</td>
    <td>
    Click [Start], [All Programs], [H2], and [H2 Console (Command Line)]<br />
    When using the Sun JDK 1.5, a window with the title 'H2 Console ' should appear.
    When using the Sun JDK 1.6, an icon will be added to the system tray:
    <img src="images/db-16.png" alt="H2 database icon" /><br />
    If you don't get the window and the system tray icon,
    then maybe Java is not installed correctly (in this case, try another way to start the application).
    A browser window should open and point to the login page at <code>http://localhost:8082</code>.
    </td>
</tr>
<tr>
    <td>Windows</td>
    <td>
    Open a file browser, navigate to <code>h2/bin</code>, and
    double click on <code>h2.bat</code>.<br />
    A console window appears. If there is a problem, you will see an error message
    in this window. A browser window will open and point to the login page
    (URL: <code>http://localhost:8082</code>).
    </td>
</tr>
<tr>
    <td>Any</td>
    <td>
    Double click on the <code>h2*.jar</code> file.
    This only works if the <code>.jar</code> suffix is associated with Java.
    </td>
</tr>
<tr>
    <td>Any</td>
    <td>
    Open a console window, navigate to the directory <code>h2/bin</code>, and type:
    <pre>java -jar h2*.jar</pre>
    </td>
</tr>
</table>

<h3>Firewall</h3>
<p>
If you start the server, you may get a security warning from the firewall (if you have installed one).
If you don't want other computers in the network to access the application on your machine, you can
let the firewall block those connections. The connection from the local machine will still work.
Only if you want other computers to access the database on this computer, you need allow remote connections
in the firewall.
</p>
<p>
It has been reported that when using Kaspersky 7.0 with firewall, the H2 Console is very slow when
connecting over the IP address. A workaround is to connect using 'localhost'.
</p>
<p>
A small firewall is already built into the server: other computers may not connect to the server by default.
To change this, go to 'Preferences' and select 'Allow connections from other computers'.
</p>

<h3>Testing Java</h3>
<p>
To find out which version of Java is installed, open a command prompt and type:
</p>
<pre>
java -version
</pre>
<p>
If you get an error message, you may need to add the Java binary directory to the path environment variable.
</p>

<h3>Error Message 'Port may be in use'</h3>
<p>
You can only start one instance of the H2 Console,
otherwise you will get the following error message:
"The Web server could not be started. Possible cause: another server is already running...".
It is possible to start multiple console applications on the same computer (using different ports),
but this is usually not required as the console supports multiple concurrent connections.
</p>

<h3>Using another Port</h3>
<p>
If the default port of the H2 Console is already in use by another application,
then a different port needs to be configured. The settings are stored in a properties file.
For details, see <a href="#console_settings">Settings of the H2 Console</a>.
The relevant entry is <code>webPort</code>.
</p>
<p>
If no port is specified for the TCP and PG servers, each service will try to listen on its default port.
If the default port is already in use, a random port is used.
</p>

<h3>Connecting to the Server using a Browser</h3>
<p>
If the server started successfully, you can connect to it using a web browser.
Javascript needs to be enabled.
If you started the server on the same computer as the browser, open the URL <code>http://localhost:8082</code>.
If you want to connect to the application from another computer, you need to provide the IP address of the server, for example:
<code>http://192.168.0.2:8082</code>.
If you enabled SSL on the server side, the URL needs to start with <code>https://</code>.
</p>

<h3>Multiple Concurrent Sessions</h3>
<p>
Multiple concurrent browser sessions are supported. As that the database objects reside on the server,
the amount of concurrent work is limited by the memory available to the server application.
</p>

<h3>Login</h3>
<p>
At the login page, you need to provide connection information to connect to a database.
Set the JDBC driver class of your database, the JDBC URL, user name, and password.
If you are done, click [Connect].
</p><p>
You can save and reuse previously saved settings. The settings are stored in a properties file
(see <a href="#console_settings">Settings of the H2 Console</a>).
</p>

<h3>Error Messages</h3>
<p>
Error messages in are shown in red. You can show/hide the stack trace of the exception
by clicking on the message.
</p>

<h3>Adding Database Drivers</h3>
<p>
To register additional JDBC drivers (MySQL, PostgreSQL, HSQLDB,...),
add the jar file names to the environment variables <code>H2DRIVERS</code> or <code>CLASSPATH</code>.
Example (Windows): to add the HSQLDB JDBC driver
<code>C:\Programs\hsqldb\lib\hsqldb.jar</code>, set the environment variable
<code>H2DRIVERS</code> to
<code>C:\Programs\hsqldb\lib\hsqldb.jar</code>.
</p><p>
Multiple drivers can be set; entries need to be separated by <code>;</code> (Windows)
or <code>:</code> (other operating systems).
Spaces in the path names are supported. The settings must not be quoted.
</p>

<h3>Using the H2 Console</h3>
<p>
The H2 Console application has three main panels: the toolbar on top, the tree on the left, and the query/result panel on the right.
The database objects (for example, tables) are listed on the left.
Type a SQL command in the query panel and click [Run]. The result appears just below the command.
</p>

<h3>Inserting Table Names or Column Names</h3>
<p>
To insert table and column names into the script, click on the item in the tree.
If you click on a table while the query is empty, then <code>SELECT * FROM ...</code> is added.
While typing a query, the table that was used is expanded in the tree.
For example if you type <code>SELECT * FROM TEST T WHERE T.</code> then the table TEST is expanded.
</p>

<h3>Disconnecting and Stopping the Application</h3>
<p>
To log out of the database, click [Disconnect] in the toolbar panel.
However, the server is still running and ready to accept new sessions.
</p><p>
To stop the server, right click on the system tray icon and select [Exit].
If you don't have the system tray icon,
navigate to [Preferences] and click [Shutdown],
press [Ctrl]+[C] in the console where the server was started (Windows),
or close the console window.
</p>

<h2 id="console_syntax">Special H2 Console Syntax</h2>
<p>
The H2 Console supports a few built-in commands.
Those are interpreted within the H2 Console, so they work with any database.
Built-in commands need to be at the beginning of a statement (before any remarks),
otherwise they are not parsed correctly. If in doubt, add <code>;</code> before the command.
</p>
<table class="main">
    <tr>
        <th>Command(s)</th>
        <th>Description</th>
    </tr>
    <tr>
        <td class="notranslate">
            @autocommit_true;<br />
            @autocommit_false;
        </td>
        <td>
            Enable or disable autocommit.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @cancel;
        </td>
        <td>
            Cancel the currently running statement.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @columns null null TEST;<br />
            @index_info&nbsp;null&nbsp;null&nbsp;TEST;<br />
            @tables;<br />
            @tables null null TEST;<br />
        </td>
        <td>
            Call the corresponding <code>DatabaseMetaData.get</code> method.
            Patterns are case sensitive (usually identifiers are uppercase).
            For information about the parameters, see the Javadoc documentation.
            Missing parameters at the end of the line are set to null. The complete list of metadata commands is:
            <code>
            @attributes, @best_row_identifier, @catalogs, @columns,
            @column_privileges, @cross_references, @exported_keys,
            @imported_keys, @index_info,  @primary_keys, @procedures,
            @procedure_columns, @schemas, @super_tables, @super_types,
            @tables, @table_privileges, @table_types, @type_info, @udts,
            @version_columns
            </code>
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @edit select * from test;
        </td>
        <td>
            Use an updatable result set.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @generated&nbsp;insert&nbsp;into&nbsp;test()&nbsp;values();
        </td>
        <td>
            Show the result of <code>Statement.getGeneratedKeys()</code>.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @history;
        </td>
        <td>
            List the command history.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @info;
        </td>
        <td>
            Display the result of various <code>Connection</code> and <code>DatabaseMetaData</code> methods.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @list select * from test;
        </td>
        <td>
            Show the result set in list format (each column on its own line, with row numbers).
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @loop 1000 select ?, ?/*rnd*/;<br />
            @loop 1000 @statement select ?;
        </td>
        <td>
            Run the statement this many times.
            Parameters (<code>?</code>) are set using a loop from 0 up to x - 1.
            Random values are used for each <code>?/*rnd*/</code>.
            A Statement object is used instead of a PreparedStatement if <code>@statement</code> is used.
            Result sets are read until <code>ResultSet.next()</code> returns <code>false</code>.
            Timing information is printed.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @maxrows&nbsp;20;
        </td>
        <td>
            Set the maximum number of rows to display.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @memory;
        </td>
        <td>
            Show the used and free memory. This will call <code>System.gc()</code>.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @meta&nbsp;select&nbsp;1;
        </td>
        <td>
            List the <code>ResultSetMetaData</code> after running the query.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @parameter_meta&nbsp;select&nbsp;?;
        </td>
        <td>
            Show the result of the <code>PreparedStatement.getParameterMetaData()</code> calls.
            The statement is not executed.
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @prof_start;<br />
            call&nbsp;hash('SHA256',&nbsp;'',&nbsp;1000000);<br />
            @prof_stop;
        </td>
        <td>
            Start/stop the built-in profiling tool.
            The top 3 stack traces of the statement(s) between start and stop are listed
            (if there are 3).
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @prof_stop;<br />
            @sleep 10;<br />
            @prof_stop;
        </td>
        <td>
            Sleep for a number of seconds. Used to profile a long running query or
            operation that is running in another session (but in the same process).
        </td>
    </tr>
    <tr>
        <td class="notranslate">
            @transaction_isolation;<br />
            @transaction_isolation&nbsp;2;
        </td>
        <td>
            Display (without parameters) or change
            (with parameters 1, 2, 4, 8) the transaction isolation level.
        </td>
    </tr>
</table>

<h2 id="console_settings">Settings of the H2 Console</h2>
<p>
The settings of the H2 Console are stored in a configuration file
called <code>.h2.server.properties</code> in you user home directory.
For Windows installations, the user home directory is usually <code>C:\Documents and Settings\[username]</code>.
The configuration file contains the settings of the application and is automatically created when the H2 Console is first started.
Supported settings are:
</p>
<ul><li><code>webAllowOthers</code>: allow other computers to connect.
</li><li><code>webPort</code>: the port of the H2 Console
</li><li><code>webSSL</code>: use encrypted (HTTPS) connections.
</li></ul>
<p>
In addition to those settings, the properties of the last recently used connection
are listed in the form
<code>&lt;number&gt;=&lt;name&gt;|&lt;driver&gt;|&lt;url&gt;|&lt;user&gt;</code>
using the escape character <code>\</code>.
Example:
<code>1=Generic H2 (Embedded)|org.h2.Driver|jdbc\:h2\:~/test|sa</code>
</p>

<h2 id="connecting_using_jdbc">Connecting to a Database using JDBC</h2>
<p>
To connect to a database, a Java application first needs to load the database driver,
and then get a connection. A simple way to do that is using the following code:
</p>
<pre>
import java.sql.*;
public class Test {
    public static void main(String[] a)
            throws Exception {
        Class.forName("org.h2.Driver");
        Connection conn = DriverManager.
            getConnection("jdbc:h2:~/test", "sa", "");
        // add application code here
        conn.close();
    }
}
</pre>
<p>
This code first loads the driver (<code>Class.forName(...)</code>)
and then opens a connection (using <code>DriverManager.getConnection()</code>).
The driver name is <code>"org.h2.Driver"</code>.
The database URL always needs to start with <code>jdbc:h2:</code>
to be recognized by this database. The second parameter in the <code>getConnection()</code> call
is the user name (<code>sa</code> for System Administrator in this example). The third parameter is the password.
In this database, user names are not case sensitive, but passwords are.
</p>

<h2 id="creating_new_databases">Creating New Databases</h2>
<p>
By default, if the database specified in the URL does not yet exist, a new (empty)
database is created automatically. The user that created the database automatically becomes
the administrator of this database.
</p>
<p>
Auto-creating new database can be disabled, see
<a href="features.html#database_only_if_exists">Opening a Database Only if it Already Exists</a>.
</p>

<h2 id="using_server">Using the Server</h2>
<p>
H2 currently supports three server: a web server (for the H2 Console),
a TCP server (for client/server connections) and an PG server (for PostgreSQL clients).
Please note that only the web server supports browser connections.
The servers can be started in different ways, one is using the <code>Server</code> tool.
Starting the server doesn't open a database - databases are opened as soon as a client connects.
</p>

<h3>Starting the Server Tool from Command Line</h3>
<p>
To start the <code>Server</code> tool from the command line with the default settings, run:
</p>
<pre>
java -cp h2*.jar org.h2.tools.Server
</pre>
<p>
This will start the tool with the default options. To get the list of options and default values, run:
</p>
<pre>
java -cp h2*.jar org.h2.tools.Server -?
</pre>
<p>
There are options available to use other ports, and start or not start parts.
</p>

<h3>Connecting to the TCP Server</h3>
<p>
To remotely connect to a database using the TCP server, use the following driver and database URL:
</p>
<ul>
<li>JDBC driver class: <code>org.h2.Driver</code>
</li><li>Database URL: <code>jdbc:h2:tcp://localhost/~/test</code>
</li></ul>
<p>
For details about the database URL, see also in Features.
Please note that you can't connection with a web browser to this URL.
You can only connect using a H2 client (over JDBC).
</p>

<h3>Starting the TCP Server within an Application</h3>
<p>
Servers can also be started and stopped from within an application. Sample code:
</p>
<pre>
import org.h2.tools.Server;
...
// start the TCP Server
Server server = Server.createTcpServer(args).start();
...
// stop the TCP Server
server.stop();
</pre>

<h3>Stopping a TCP Server from Another Process</h3>
<p>
The TCP server can be stopped from another process.
To stop the server from the command line, run:
</p>
<pre>
java org.h2.tools.Server -tcpShutdown tcp://localhost:9092
</pre>
<p>
To stop the server from a user application, use the following code:
</p>
<pre>
org.h2.tools.Server.shutdownTcpServer("tcp://localhost:9094");
</pre>
<p>
This function will only stop the TCP server.
If other server were started in the same process, they will continue to run.
To avoid recovery when the databases are opened the next time,
all connections to the databases should be closed before calling this method.
To stop a remote server, remote connections must be enabled on the server.
Shutting down a TCP server can be protected using the option <code>-tcpPassword</code>
(the same password must be used to start and stop the TCP server).
</p>

<h2 id="using_hibernate">Using Hibernate</h2>
<p>
This database supports Hibernate version 3.1 and newer. You can use the HSQLDB Dialect,
or the native H2 Dialect. Unfortunately the H2 Dialect included in some old versions of Hibernate was buggy.
A <a href="http://opensource.atlassian.com/projects/hibernate/browse/HHH-3401">patch
for Hibernate</a> has been submitted and is now applied.
You can rename it to <code>H2Dialect.java</code> and include this as a patch in your application,
or upgrade to a version of Hibernate where this is fixed.
</p>
<p>
When using Hibernate, try to use the <code>H2Dialect</code> if possible.
When using the <code>H2Dialect</code>,
compatibility modes such as <code>MODE=MySQL</code> are not supported.
When using such a compatibility mode, use the Hibernate dialect for the
corresponding database instead of the <code>H2Dialect</code>;
but please note H2 does not support all features of all databases.
</p>

<h2 id="using_toplink">Using TopLink and Glassfish</h2>
<p>
To use H2 with Glassfish (or Sun AS), set the Datasource Classname to
<code>org.h2.jdbcx.JdbcDataSource</code>. You can set this in the GUI
at Application Server - Resources - JDBC - Connection Pools,
or by editing the file <code>sun-resources.xml</code>: at element
<code>jdbc-connection-pool</code>, set the attribute
<code>datasource-classname</code> to <code>org.h2.jdbcx.JdbcDataSource</code>.
</p>
<p>
The H2 database is compatible with HSQLDB and PostgreSQL.
To take advantage of H2 specific features, use the <code>H2Platform</code>.
The source code of this platform is included in H2 at
<code>src/tools/oracle/toplink/essentials/platform/database/DatabasePlatform.java.txt</code>.
You will need to copy this file to your application, and rename it to .java.
To enable it, change the following setting in persistence.xml:
</p>
<pre>
&lt;property
    name="toplink.target-database"
    value="oracle.toplink.essentials.platform.database.H2Platform"/&gt;
</pre>
<p>
In old versions of Glassfish, the property name is <code>toplink.platform.class.name</code>.
</p>
<p>
To use H2 within Glassfish, copy the h2*.jar to the directory <code>glassfish/glassfish/lib</code>.
</p>

<h2 id="using_eclipselink">Using EclipseLink</h2>
<p>
To use H2 in EclipseLink, use the platform class <code>org.eclipse.persistence.platform.database.H2Platform</code>.
If this platform is not available in your version of EclipseLink, you can use the OraclePlatform instead in many case.
See also <a href="http://wiki.eclipse.org/EclipseLink/Development/Incubator/Extensions/H2Platform">H2Platform</a>.
</p>

<h2 id="using_activemq">Using Apache ActiveMQ</h2>
<p>
When using H2 as the backend database for Apache ActiveMQ, please use the <code>TransactDatabaseLocker</code>
instead of the default locking mechanism. Otherwise the database file will grow without bounds. The problem is that the
default locking mechanism uses an uncommitted <code>UPDATE</code> transaction, which keeps the transaction log
from shrinking (causes the database file to grow). Instead of using an <code>UPDATE</code> statement, the <code>TransactDatabaseLocker</code> uses
<code>SELECT ... FOR UPDATE</code> which is not problematic.
To use it, change the ApacheMQ configuration element <code>&lt;jdbcPersistenceAdapter&gt;</code> element,  property
<code>databaseLocker="org.apache.activemq.store.jdbc.adapter.TransactDatabaseLocker"</code>.
However, using the MVCC mode will again result in the same problem. Therefore, please do not use the MVCC mode in this case.
Another (more dangerous) solution is to set <code>useDatabaseLock</code> to false.
</p>

<h2 id="using_netbeans">Using H2 within NetBeans</h2>
<p>
The project <a href="http://kenai.com/projects/nbh2">H2 Database Engine Support For NetBeans</a>
allows you to start and stop the H2 server from within the IDE.
</p>
<p>
There is a known issue when using the Netbeans SQL Execution Window:
before executing a query, another query in the form <code>SELECT COUNT(*) FROM &lt;query&gt;</code> is run.
This is a problem for queries that modify state, such as <code>SELECT SEQ.NEXTVAL</code>.
In this case, two sequence values are allocated instead of just one.
</p>

<h2 id="using_jooq">Using H2 with jOOQ</h2>
<p>
jOOQ adds a thin layer on top of JDBC, allowing for type-safe SQL construction,
including advanced SQL, stored procedures and advanced data types.
jOOQ takes your database schema as a base for code generation.
If this is your example schema:
</p>
<pre>
CREATE TABLE USER (ID INT, NAME VARCHAR(50));
</pre>
<p>
then run the jOOQ code generator on the command line using this command:
</p>
<pre>
java -cp jooq.jar;jooq-meta.jar;jooq-codegen.jar;h2-1.3.158.jar;.
org.jooq.util.GenerationTool /codegen.xml
</pre>
<p>
...where <code>codegen.xml</code> is on the classpath and contains this information
</p>
<pre>
&lt;?xml version="1.0" encoding="UTF-8" standalone="yes"?>
&lt;configuration xmlns="http://www.jooq.org/xsd/jooq-codegen-2.3.0.xsd">
    &lt;jdbc>
        &lt;driver>org.h2.Driver&lt;/driver>
        &lt;url>jdbc:h2:~/test&lt;/url>
        &lt;user>sa&lt;/user>
        &lt;password>&lt;/password>
    &lt;/jdbc>
    &lt;generator>
        &lt;name>org.jooq.util.DefaultGenerator&lt;/name>
        &lt;database>
            &lt;name>org.jooq.util.h2.H2Database&lt;/name>
            &lt;includes>.*&lt;/includes>
            &lt;excludes>&lt;/excludes>
            &lt;inputSchema>PUBLIC&lt;/inputSchema>
        &lt;/database>
        &lt;generate>&lt;/generate>
        &lt;target>
            &lt;packageName>org.jooq.h2.generated&lt;/packageName>
            &lt;directory>./src&lt;/directory>
        &lt;/target>
    &lt;/generator>
&lt;/configuration>
</pre>
<p>
Using the generated source, you can query the database as follows:
</p>
<pre>
Factory create = new H2Factory(connection);
Result&lt;UserRecord&gt; result =
create.selectFrom(USER)
    .where(NAME.like("Johnny%"))
    .orderBy(ID)
    .fetch();
</pre>
<p>
See more details on <a href="http://www.jooq.org">jOOQ Homepage</a>
and in the <a href="http://www.jooq.org/tutorial.php">jOOQ Tutorial</a>
</p>

<h2 id="web_applications">Using Databases in Web Applications</h2>
<p>
There are multiple ways to access a database from within web
applications. Here are some examples if you use Tomcat or JBoss.
</p>

<h3>Embedded Mode</h3>
<p>
The (currently) simplest solution is to use the database in the
embedded mode, that means open a connection in your application when
it starts (a good solution is using a Servlet Listener, see below), or
when a session starts. A database can be accessed from multiple
sessions and applications at the same time, as long as they run in the
same process. Most Servlet Containers (for example Tomcat) are just
using one process, so this is not a problem (unless you run Tomcat in
clustered mode). Tomcat uses multiple threads and multiple
classloaders. If multiple applications access the same database at the
same time, you need to put the database jar in the <code>shared/lib</code> or
<code>server/lib</code> directory. It is a good idea to open the database when the
web application starts, and close it when the web application stops.
If using multiple applications, only one (any) of them needs to do
that. In the application, an idea is to use one connection per
Session, or even one connection per request (action). Those
connections should be closed after use if possible (but it's not that
bad if they don't get closed).
</p>

<h3>Server Mode</h3>
<p>
The server mode is similar, but it allows you to run the server in another process.
</p>

<h3>Using a Servlet Listener to Start and Stop a Database</h3>
<p>
Add the h2*.jar file to your web application, and
add the following snippet to your web.xml file (between the
<code>context-param</code> and the <code>filter</code> section):
</p>
<pre>
&lt;listener&gt;
    &lt;listener-class&gt;org.h2.server.web.DbStarter&lt;/listener-class&gt;
&lt;/listener&gt;
</pre>
<p>
For details on how to access the database, see the file <code>DbStarter.java</code>.
By default this tool opens an embedded connection
using the database URL <code>jdbc:h2:~/test</code>,
user name <code>sa</code>, and password <code>sa</code>.
If you want to use this connection within your servlet, you can access as follows:
</p>
<pre>
Connection conn = getServletContext().getAttribute("connection");
</pre>
<p>
<code>DbStarter</code> can also start the TCP server, however this is disabled by default.
To enable it, use the parameter <code>db.tcpServer</code> in the file <code>web.xml</code>.
Here is the complete list of options.
These options need to be placed between the <code>description</code> tag
and the <code>listener</code> / <code>filter</code> tags:
</p>
<pre>
&lt;context-param&gt;
    &lt;param-name&gt;db.url&lt;/param-name&gt;
    &lt;param-value&gt;jdbc:h2:~/test&lt;/param-value&gt;
&lt;/context-param&gt;
&lt;context-param&gt;
    &lt;param-name&gt;db.user&lt;/param-name&gt;
    &lt;param-value&gt;sa&lt;/param-value&gt;
&lt;/context-param&gt;
&lt;context-param&gt;
    &lt;param-name&gt;db.password&lt;/param-name&gt;
    &lt;param-value&gt;sa&lt;/param-value&gt;
&lt;/context-param&gt;
&lt;context-param&gt;
    &lt;param-name&gt;db.tcpServer&lt;/param-name&gt;
    &lt;param-value&gt;-tcpAllowOthers&lt;/param-value&gt;
&lt;/context-param&gt;
</pre>
<p>
When the web application is stopped, the database connection will be closed automatically.
If the TCP server is started within the <code>DbStarter</code>, it will also be stopped automatically.
</p>

<h3>Using the H2 Console Servlet</h3>
<p>
The H2 Console is a standalone application and includes its own web server, but it can be
used as a servlet as well. To do that, include the the <code>h2*.jar</code> file in your application, and
add the following configuration to your <code>web.xml</code>:
</p>
<pre>
&lt;servlet&gt;
    &lt;servlet-name&gt;H2Console&lt;/servlet-name&gt;
    &lt;servlet-class&gt;org.h2.server.web.WebServlet&lt;/servlet-class&gt;
    &lt;!--
    &lt;init-param&gt;
        &lt;param-name&gt;webAllowOthers&lt;/param-name&gt;
        &lt;param-value&gt;&lt;/param-value&gt;
    &lt;/init-param&gt;
    &lt;init-param&gt;
        &lt;param-name&gt;trace&lt;/param-name&gt;
        &lt;param-value&gt;&lt;/param-value&gt;
    &lt;/init-param&gt;
    --&gt;
    &lt;load-on-startup&gt;1&lt;/load-on-startup&gt;
&lt;/servlet&gt;
&lt;servlet-mapping&gt;
    &lt;servlet-name&gt;H2Console&lt;/servlet-name&gt;
    &lt;url-pattern&gt;/console/*&lt;/url-pattern&gt;
&lt;/servlet-mapping&gt;
</pre>
<p>
For details, see also <code>src/tools/WEB-INF/web.xml</code>.
</p>
<p>
To create a web application with just the H2 Console, run the following command:
</p>
<pre>
build warConsole
</pre>

<h2 id="android">Android</h2>
<p>
You can use this database on an Android device (using the Dalvik VM) instead of or in addition to SQLite.
So far, only very few tests and benchmarks were run, but it seems that performance is similar to SQLite,
except for opening and closing a database, which is not yet optimized in H2
(H2 takes about 0.2 seconds, and SQLite about 0.02 seconds).
Read operations seem to be a bit faster than SQLite, and write operations seem to be slower.
So far, only very few tests have been run, and everything seems to work as expected.
Fulltext search was not yet tested, however the native fulltext search should work.
</p>
<p>
Reasons to use H2 instead of SQLite are:
</p>
<ul><li>Full Unicode support including UPPER() and LOWER().
</li><li>Streaming API for BLOB and CLOB data.
</li><li>Fulltext search.
</li><li>Multiple connections.
</li><li>User defined functions and triggers.
</li><li>Database file encryption.
</li><li>Reading and writing CSV files (this feature can be used out side the database as well).
</li><li>Referential integrity and check constraints.
</li><li>Better data type and SQL support.
</li><li>In-memory databases, read-only databases, linked tables.
</li><li>Better compatibility with other databases which simplifies porting applications.
</li><li>Possibly better performance (so far for read operations).
</li><li>Server mode (accessing a database on a different machine over TCP/IP).
</li></ul>
<p>
Currently only the JDBC API is supported (it is planned to support the Android database API in future releases).
Both the regular H2 jar file and the smaller <code>h2small-*.jar</code> can be used.
To create the smaller jar file, run the command <code>./build.sh jarSmall</code> (Linux / Mac OS)
or <code>build.bat jarSmall</code> (Windows).
</p>
<p>
The database files needs to be stored in a place that is accessible for the application.
Example:
</p>
<pre>
String url = "jdbc:h2:/data/data/" +
    "com.example.hello" +
    "/data/hello" +
    ";FILE_LOCK=FS" +
    ";PAGE_SIZE=1024" +
    ";CACHE_SIZE=8192";
Class.forName("org.h2.Driver");
conn = DriverManager.getConnection(url);
...
</pre>
<p>
Limitations: Using a connection pool is currently not supported, because the required <code>javax.sql.</code> classes are not available on Android.
</p>

<h2 id="csv">CSV (Comma Separated Values) Support</h2>
<p>
The CSV file support can be used inside the database using the functions
<code>CSVREAD</code> and <code>CSVWRITE</code>,
or it can be used outside the database as a standalone tool.
</p>

<h3>Reading a CSV File from Within a Database</h3>
<p>
A CSV file can be read using the function <code>CSVREAD</code>. Example:
</p>
<pre>
SELECT * FROM CSVREAD('test.csv');
</pre>
<p>
Please note for performance reason, <code>CSVREAD</code> should not be used inside a join.
Instead, import the data first (possibly into a temporary table), create the required indexes
if necessary, and then query this table.
</p>

<h3>Importing Data from a CSV File</h3>
<p>
A fast way to load or import data (sometimes called 'bulk load') from a CSV file is
to combine table creation with import.
Optionally, the column names and data types can be set when creating the table.
Another option is to use <code>INSERT INTO ... SELECT</code>.
</p>
<pre>
CREATE TABLE TEST AS SELECT * FROM CSVREAD('test.csv');
CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR(255))
    AS SELECT * FROM CSVREAD('test.csv');
</pre>

<h3>Writing a CSV File from Within a Database</h3>
<p>
The built-in function <code>CSVWRITE</code> can be used to create a CSV file from a query.
Example:
</p>
<pre>
CREATE TABLE TEST(ID INT, NAME VARCHAR);
INSERT INTO TEST VALUES(1, 'Hello'), (2, 'World');
CALL CSVWRITE('test.csv', 'SELECT * FROM TEST');
</pre>

<h3>Writing a CSV File from a Java Application</h3>
<p>
The <code>Csv</code> tool can be used in a Java application even when not using a database at all.
Example:
</p>
<pre>
import java.sql.*;
import org.h2.tools.Csv;
import org.h2.tools.SimpleResultSet;
public class TestCsv {
    public static void main(String[] args) throws Exception {
        SimpleResultSet rs = new SimpleResultSet();
        rs.addColumn("NAME", Types.VARCHAR, 255, 0);
        rs.addColumn("EMAIL", Types.VARCHAR, 255, 0);
        rs.addRow("Bob Meier", "bob.meier@abcde.abc");
        rs.addRow("John Jones", "john.jones@abcde.abc");
        new Csv().write("data/test.csv", rs, null);
    }
}
</pre>

<h3>Reading a CSV File from a Java Application</h3>
<p>
It is possible to read a CSV file without opening a database.
Example:
</p>
<pre>
import java.sql.*;
import org.h2.tools.Csv;
public class TestCsv {
    public static void main(String[] args) throws Exception {
        ResultSet rs = new Csv().read("data/test.csv", null, null);
        ResultSetMetaData meta = rs.getMetaData();
        while (rs.next()) {
            for (int i = 0; i &lt; meta.getColumnCount(); i++) {
                System.out.println(
                    meta.getColumnLabel(i + 1) + ": " +
                    rs.getString(i + 1));
            }
            System.out.println();
        }
        rs.close();
    }
}
</pre>

<h2 id="upgrade_backup_restore">Upgrade, Backup, and Restore</h2>

<h3>Database Upgrade</h3>
<p>
The recommended way to upgrade from one version of the database engine to the next
version is to create a backup of the database (in the form of a SQL script) using the old engine,
and then execute the SQL script using the new engine.
</p>

<h3>Backup using the Script Tool</h3>
<p>
The recommended way to backup a database is to create a compressed SQL script file.
This will result in a small, human readable, and database version independent backup.
Creating the script will also verify the checksums of the database file.
The <code>Script</code> tool is ran as follows:
</p>
<pre>
java org.h2.tools.Script -url jdbc:h2:~/test -user sa -script test.zip -options compression zip
</pre>
<p>
It is also possible to use the SQL command <code>SCRIPT</code> to create the backup of the database.
For more information about the options, see the SQL command <code>SCRIPT</code>.
The backup can be done remotely, however the file will be created on the server side.
The built in FTP server could be used to retrieve the file from the server.
</p>

<h3>Restore from a Script</h3>
<p>
To restore a database from a SQL script file, you can use the <code>RunScript</code> tool:
</p>
<pre>
java org.h2.tools.RunScript -url jdbc:h2:~/test -user sa -script test.zip -options compression zip
</pre>
<p>
For more information about the options, see the SQL command <code>RUNSCRIPT</code>.
The restore can be done remotely, however the file needs to be on the server side.
The built in FTP server could be used to copy the file to the server.
It is also possible to use the SQL command <code>RUNSCRIPT</code> to execute a SQL script.
SQL script files may contain references to other script files, in the form of
<code>RUNSCRIPT</code> commands. However, when using the server mode, the references script files
need to be available on the server side.
</p>

<h3>Online Backup</h3>
<p>
The <code>BACKUP</code> SQL statement and the <code>Backup</code> tool both create a zip file
with the database file. However, the contents of this file are not human readable.
</p><p>
The resulting backup is transactionally consistent, meaning the consistency and atomicity rules apply.
</p>
<pre>
BACKUP TO 'backup.zip'
</pre>
<p>
The <code>Backup</code> tool (<code>org.h2.tools.Backup</code>) can not be used to create a online backup;
the database must not be in use while running this program.
</p>
<p>
Creating a backup by copying the database files while the database is running is not supported,
except if the file systems support creating snapshots.
With other file systems, it can't be guaranteed that the data is copied in the right order.
</p>

<h2 id="command_line_tools">Command Line Tools</h2>
<p>
This database comes with a number of command line tools. To get more information about a tool,
start it with the parameter '-?', for example:
</p>
<pre>
java -cp h2*.jar org.h2.tools.Backup -?
</pre>
<p>
The command line tools are:
</p>
<ul><li><code>Backup</code> creates a backup of a database.
</li><li><code>ChangeFileEncryption</code> allows changing the file encryption password or algorithm of a database.
</li><li><code>Console</code> starts the browser based H2 Console.
</li><li><code>ConvertTraceFile</code> converts a .trace.db file to a Java application and SQL script.
</li><li><code>CreateCluster</code> creates a cluster from a standalone database.
</li><li><code>DeleteDbFiles</code> deletes all files belonging to a database.
</li><li><code>Recover</code> helps recovering a corrupted database.
</li><li><code>Restore</code> restores a backup of a database.
</li><li><code>RunScript</code> runs a SQL script against a database.
</li><li><code>Script</code> allows converting a database to a SQL script for backup or migration.
</li><li><code>Server</code> is used in the server mode to start a H2 server.
</li><li><code>Shell</code> is a command line database tool.
</li></ul>
<p>
The tools can also be called from an application by calling the main or another public method.
For details, see the Javadoc documentation.
</p>

<h2 id="shell_tool">The Shell Tool</h2>
<p>
The Shell tool is a simple interactive command line tool. To start it, type:
</p>
<pre>
java -cp h2*.jar org.h2.tools.Shell
</pre>
<p>
You will be asked for a database URL, JDBC driver, user name, and password.
The connection setting can also be set as command line parameters.
After connecting, you will get the list of options.
The built-in commands don't need to end with a semicolon, but
SQL statements are only executed if the line ends with a semicolon <code>;</code>.
This allows to enter multi-line statements:
</p>
<pre>
sql&gt; select * from test
...&gt; where id = 0;
</pre>
<p>
By default, results are printed as a table. For results with many column, consider using the list mode:
</p>
<pre>
sql&gt; list
Result list mode is now on
sql&gt; select * from test;
ID  : 1
NAME: Hello

ID  : 2
NAME: World
(2 rows, 0 ms)
</pre>

<h2 id="open_office">Using OpenOffice Base</h2>
<p>
OpenOffice.org Base supports database access over the JDBC API. To connect to a H2 database
using OpenOffice Base, you first need to add the JDBC driver to OpenOffice.
The steps to connect to a H2 database are:
</p>
<ul><li>Start OpenOffice Writer, go to [Tools], [Options]
</li><li>Make sure you have selected a Java runtime environment in OpenOffice.org / Java
</li><li>Click [Class Path...], [Add Archive...]
</li><li>Select your h2 jar file (location is up to you, could be wherever you choose)
</li><li>Click [OK] (as much as needed), stop OpenOffice (including the Quickstarter)
</li><li>Start OpenOffice Base
</li><li>Connect to an existing database; select [JDBC]; [Next]
</li><li>Example datasource URL: <code>jdbc:h2:~/test</code>
</li><li>JDBC driver class: <code>org.h2.Driver</code>
</li></ul>
<p>
Now you can access the database stored in the current users home directory.
</p>
<p>
To use H2 in NeoOffice (OpenOffice without X11):
</p>
<ul><li>In NeoOffice, go to [NeoOffice], [Preferences]
</li><li>Look for the page under [NeoOffice], [Java]
</li><li>Click [Class Path], [Add Archive...]
</li><li>Select your h2 jar file (location is up to you, could be wherever you choose)
</li><li>Click [OK] (as much as needed), restart NeoOffice.
</li></ul>
<p>
Now, when creating a new database using the "Database Wizard" :
</p>
<ul><li>Click [File], [New], [Database].
</li><li>Select [Connect to existing database] and the select [JDBC]. Click next.
</li><li>Example datasource URL: <code>jdbc:h2:~/test</code>
</li><li>JDBC driver class: <code>org.h2.Driver</code>
</li></ul>
<p>
Another solution to use H2 in NeoOffice is:
</p>
<ul><li>Package the h2 jar within an extension package
</li><li>Install it as a Java extension in NeoOffice
</li></ul>
<p>
This can be done by create it using the NetBeans OpenOffice plugin.
See also <a href="http://wiki.services.openoffice.org/wiki/Extensions_development_java">Extensions Development</a>.
</p>

<h2 id="web_start">Java Web Start / JNLP</h2>
<p>
When using Java Web Start / JNLP (Java Network Launch Protocol), permissions tags must be set in the .jnlp file,
and the application .jar file must be signed. Otherwise, when trying to write to the file system, the following
exception will occur: <code>java.security.AccessControlException</code>:
access denied (<code>java.io.FilePermission ... read</code>).
Example permission tags:
</p>
<pre>
&lt;security&gt;
    &lt;all-permissions/&gt;
&lt;/security&gt;
</pre>

<h2 id="connection_pool">Using a Connection Pool</h2>
<p>
For H2, opening a connection is fast if the database is already open.
Still, using a connection pool improves performance if you open and close connections a lot.
A simple connection pool is included in H2. It is based on the
<a href="http://www.source-code.biz/snippets/java/8.htm">Mini Connection Pool Manager</a>
from Christian d'Heureuse. There are other, more complex, open source connection pools available,
for example the <a href="http://jakarta.apache.org/commons/dbcp/">Apache Commons DBCP</a>.
For H2, it is about twice as faster to get a connection from the built-in connection pool than to get
one using <code>DriverManager.getConnection()</code>.The build-in connection pool is used as follows:
</p>
<pre>
import java.sql.*;
import org.h2.jdbcx.JdbcConnectionPool;
public class Test {
    public static void main(String[] args) throws Exception {
        JdbcConnectionPool cp = JdbcConnectionPool.create(
            "jdbc:h2:~/test", "sa", "sa");
        for (int i = 0; i &lt; args.length; i++) {
            Connection conn = cp.getConnection();
            conn.createStatement().execute(args[i]);
            conn.close();
        }
        cp.dispose();
    }
}
</pre>

<h2 id="fulltext">Fulltext Search</h2>
<p>
H2 includes two fulltext search implementations. One is using Apache Lucene,
and the other (the native implementation) stores the index data in special
tables in the database.
</p>

<h3>Using the Native Fulltext Search</h3>
<p>
To initialize, call:
</p>
<pre>
CREATE ALIAS IF NOT EXISTS FT_INIT FOR "org.h2.fulltext.FullText.init";
CALL FT_INIT();
</pre>
<p>
You need to initialize it in each database where you want to use it.
Afterwards, you can create a fulltext index for a table using:
</p>
<pre>
CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR);
INSERT INTO TEST VALUES(1, 'Hello World');
CALL FT_CREATE_INDEX('PUBLIC', 'TEST', NULL);
</pre>
<p>
PUBLIC is the schema name, TEST is the table name. The list of column names (comma separated) is optional,
in this case all columns are indexed. The index is updated in realtime.
To search the index, use the following query:
</p>
<pre>
SELECT * FROM FT_SEARCH('Hello', 0, 0);
</pre>
<p>
This will produce a result set that contains the query needed to retrieve the data:
</p>
<pre>
QUERY: "PUBLIC"."TEST" WHERE "ID"=1
</pre>
<p>
To get the raw data, use <code>FT_SEARCH_DATA('Hello', 0, 0);</code>.
The result contains the columns <code>SCHEMA</code> (the schema name),
<code>TABLE</code> (the table name),
<code>COLUMNS</code> (an array of column names), and
<code>KEYS</code> (an array of objects).
To join a table, use a join as in:
<code>SELECT T.* FROM FT_SEARCH_DATA('Hello', 0, 0) FT, TEST T
WHERE FT.TABLE='TEST' AND T.ID=FT.KEYS[0];</code>
</p>
<p>
You can also call the index from within a Java application:
</p>
<pre>
org.h2.fulltext.FullText.search(conn, text, limit, offset);
org.h2.fulltext.FullText.searchData(conn, text, limit, offset);
</pre>

<h3>Using the Lucene Fulltext Search</h3>
<p>
To use the Lucene full text search, you need the Lucene library in the classpath.
Currently Apache Lucene version 2.x is used by default for H2 version 1.2.x,
and Lucene version 3.x is used by default for H2 version 1.3.x.
How to do that depends on the application; if you use the H2 Console, you can add the Lucene
jar file to the environment variables <code>H2DRIVERS</code> or
<code>CLASSPATH</code>.
To initialize the Lucene fulltext search in a database, call:
</p>
<pre>
CREATE ALIAS IF NOT EXISTS FTL_INIT FOR "org.h2.fulltext.FullTextLucene.init";
CALL FTL_INIT();
</pre>
<p>
You need to initialize it in each database where you want to use it.
Afterwards, you can create a full text index for a table using:
</p>
<pre>
CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR);
INSERT INTO TEST VALUES(1, 'Hello World');
CALL FTL_CREATE_INDEX('PUBLIC', 'TEST', NULL);
</pre>
<p>
PUBLIC is the schema name, TEST is the table name. The list of column names (comma separated) is optional,
in this case all columns are indexed. The index is updated in realtime. To search the index,
use the following query:
</p>
<pre>
SELECT * FROM FTL_SEARCH('Hello', 0, 0);
</pre>
<p>
This will produce a result set that contains the query needed to retrieve the data:
</p>
<pre>
QUERY: "PUBLIC"."TEST" WHERE "ID"=1
</pre>
<p>
To get the raw data, use <code>FTL_SEARCH_DATA('Hello', 0, 0);</code>.
The result contains the columns <code>SCHEMA</code> (the schema name),
<code>TABLE</code> (the table name),
<code>COLUMNS</code> (an array of column names),
and <code>KEYS</code> (an array of objects). To join a table, use a join as in:
<code>SELECT T.* FROM FTL_SEARCH_DATA('Hello', 0, 0) FT, TEST T
WHERE FT.TABLE='TEST' AND T.ID=FT.KEYS[0];</code>
</p>
<p>
You can also call the index from within a Java application:
</p>
<pre>
org.h2.fulltext.FullTextLucene.search(conn, text, limit, offset);
org.h2.fulltext.FullTextLucene.searchData(conn, text, limit, offset);
</pre>
<p>
The Lucene fulltext search supports searching in specific column only.
Column names must be uppercase (except if the original columns are double quoted).
For column names starting with an underscore (_), another underscore needs to be added.
Example:
</p>
<pre>
CREATE ALIAS IF NOT EXISTS FTL_INIT FOR "org.h2.fulltext.FullTextLucene.init";
CALL FTL_INIT();
DROP TABLE IF EXISTS TEST;
CREATE TABLE TEST(ID INT PRIMARY KEY, FIRST_NAME VARCHAR, LAST_NAME VARCHAR);
CALL FTL_CREATE_INDEX('PUBLIC', 'TEST', NULL);
INSERT INTO TEST VALUES(1, 'John', 'Wayne');
INSERT INTO TEST VALUES(2, 'Elton', 'John');
SELECT * FROM FTL_SEARCH_DATA('John', 0, 0);
SELECT * FROM FTL_SEARCH_DATA('LAST_NAME:John', 0, 0);
CALL FTL_DROP_ALL();
</pre>
<p>
The Lucene fulltext search implementation is not synchronized internally.
If you update the database and query the fulltext search concurrently
(directly using the Java API of H2 or Lucene itself), you need to ensure
operations are properly synchronized. If this is not the case, you may get
exceptions such as <code>org.apache.lucene.store.AlreadyClosedException: this IndexReader is closed</code>.
</p>

<h2 id="user_defined_variables">User-Defined Variables</h2>
<p>
This database supports user-defined variables. Variables start with <code>@</code> and can be used wherever
expressions or parameters are allowed. Variables are not persisted and session scoped, that means only visible
from within the session in which they are defined. A value is usually assigned using the SET command:
</p>
<pre>
SET @USER = 'Joe';
</pre>
<p>
The value can also be changed using the SET() method. This is useful in queries:
</p>
<pre>
SET @TOTAL = NULL;
SELECT X, SET(@TOTAL, IFNULL(@TOTAL, 1.) * X) F FROM SYSTEM_RANGE(1, 50);
</pre>
<p>
Variables that are not set evaluate to <code>NULL</code>.
The data type of a user-defined variable is the data type
of the value assigned to it, that means it is not necessary (or possible) to declare variable names before using them.
There are no restrictions on the assigned values; large objects (LOBs) are supported as well.
Rolling back a transaction does not affect the value of a user-defined variable.
</p>

<h2 id="date_time">Date and Time</h2>
<p>
Date, time and timestamp values support ISO 8601 formatting, including time zone:
</p>
<pre>
CALL TIMESTAMP '2008-01-01 12:00:00+01:00';
</pre>
<p>
If the time zone is not set, the value is parsed using the current time zone setting of the system.
Date and time information is stored in H2 database files without time zone information.
If the database is opened using another system time zone, the date and time will be the same.
That means if you store the value '2000-01-01 12:00:00' in one time zone, then close the database
and open the database again in a different time zone, you will also get '2000-01-01 12:00:00'.
Please note that changing the time zone after the H2 driver is loaded is not supported.
</p>

<h2 id="spring">Using Spring</h2>
<h3>Using the TCP Server</h3>
<p>
Use the following configuration to start and stop the H2 TCP server using the Spring Framework:
</p>
<pre>
&lt;bean id = "org.h2.tools.Server"
            class="org.h2.tools.Server"
            factory-method="createTcpServer"
            init-method="start"
            destroy-method="stop"&gt;
    &lt;constructor-arg value="-tcp,-tcpAllowOthers,true,-tcpPort,8043" /&gt;
&lt;/bean&gt;
</pre>
<p>
The <code>destroy-method</code> will help prevent exceptions on hot-redeployment or when restarting the server.
</p>

<h3>Error Code Incompatibility</h3>
<p>
There is an incompatibility with the Spring JdbcTemplate and H2 version 1.3.154 and newer,
because of a change in the error code. This will cause the JdbcTemplate to not detect
a duplicate key condition, and so a <code>DataIntegrityViolationException</code> is thrown instead of
<code>DuplicateKeyException</code>.
See also <a href="https://jira.springsource.org/browse/SPR-8235">the issue SPR-8235</a>.
The workaround is to add the following XML file to the root of the classpath:
</p>
<pre>
&lt;beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation=
        "http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd"
    &gt;
    &lt;import resource="classpath:org/springframework/jdbc/support/sql-error-codes.xml"/&gt;
    &lt;bean id = "H2" class="org.springframework.jdbc.support.SQLErrorCodes"&gt;
        &lt;property name="badSqlGrammarCodes"&gt;
            &lt;value&gt;
                42000,42001,42101,42102,42111,42112,42121,42122,42132
            &lt;/value&gt;
        &lt;/property&gt;
        &lt;property name="duplicateKeyCodes"&gt;
            &lt;value&gt;23001,23505&lt;/value&gt;
        &lt;/property&gt;
        &lt;property name="dataIntegrityViolationCodes"&gt;
            &lt;value&gt;22003,22012,22025,23000&lt;/value&gt;
        &lt;/property&gt;
        &lt;property name="dataAccessResourceFailureCodes"&gt;
            &lt;value&gt;90046,90100,90117,90121,90126&lt;/value&gt;
        &lt;/property&gt;
        &lt;property name="cannotAcquireLockCodes"&gt;
            &lt;value&gt;50200&lt;/value&gt;
        &lt;/property&gt;
    &lt;/bean&gt;
&lt;/beans&gt;
</pre>

<h2 id="jmx">Java Management Extension (JMX)</h2>
<p>
Management over JMX is supported, but not enabled by default.
To enable JMX, append <code>;JMX=TRUE</code> to the database URL when opening the database.
Various tools support JMX, one such tool is the <code>jconsole</code>.
When opening the <code>jconsole</code>, connect to the process where the database is open
(when using the server mode, you need to connect to the server process). Then go to the <code>MBeans</code> section.
Under <code>org.h2</code> you will find one entry per database. The object name of the entry
is the database short name, plus the path (each colon is replaced with an underscore character).
</p>
<p>
The following attributes and operations are supported:
</p>
<ul><li><code>CacheSize</code>: the cache size currently in use in KB.
</li><li><code>CacheSizeMax</code> (read/write): the maximum cache size in KB.
</li><li><code>Exclusive</code>: whether this database is open in exclusive mode or not.
</li><li><code>FileReadCount</code>: the number of file read operations since the database was opened.
</li><li><code>FileSize</code>: the file size in KB.
</li><li><code>FileWriteCount</code>: the number of file write operations since the database was opened.
</li><li><code>FileWriteCountTotal</code>: the number of file write operations since the database was created.
</li><li><code>LogMode</code> (read/write): the current transaction log mode. See <code>SET LOG</code> for details.
</li><li><code>Mode</code>: the compatibility mode (<code>REGULAR</code> if no compatibility mode is used).
</li><li><code>MultiThreaded</code>: true if multi-threaded is enabled.
</li><li><code>Mvcc</code>: true if <code>MVCC</code> is enabled.
</li><li><code>ReadOnly</code>: true if the database is read-only.
</li><li><code>TraceLevel</code> (read/write): the file trace level.
</li><li><code>Version</code>: the database version in use.
</li><li><code>listSettings</code>: list the database settings.
</li><li><code>listSessions</code>: list the open sessions, including currently executing statement (if any) and locked tables (if any).
</li></ul>
<p>
To enable JMX, you may need to set the system properties <code>com.sun.management.jmxremote</code> and
<code>com.sun.management.jmxremote.port</code> as required by the JVM.
</p>
<!-- [close] { --></div></td></tr></table><!-- } --><!-- analytics --></body></html>