Skip to content
项目
群组
代码片段
帮助
正在加载...
帮助
为 GitLab 提交贡献
登录/注册
切换导航
H
h2database
项目
项目
详情
活动
周期分析
仓库
仓库
文件
提交
分支
标签
贡献者
分枝图
比较
统计图
议题
0
议题
0
列表
看板
标记
里程碑
合并请求
0
合并请求
0
CI / CD
CI / CD
流水线
作业
计划
统计图
Wiki
Wiki
代码片段
代码片段
成员
成员
折叠边栏
关闭边栏
活动
分枝图
统计图
创建新议题
作业
提交
议题看板
打开侧边栏
Administrator
h2database
Commits
d22a1a41
提交
d22a1a41
authored
4月 22, 2009
作者:
Thomas Mueller
浏览文件
操作
浏览文件
下载
电子邮件补丁
差异文件
Improve docs
上级
8ec01485
显示空白字符变更
内嵌
并排
正在显示
8 个修改的文件
包含
42 行增加
和
38 行删除
+42
-38
history.html
h2/src/docsrc/html/history.html
+1
-1
jaqu.html
h2/src/docsrc/html/jaqu.html
+19
-18
license.html
h2/src/docsrc/html/license.html
+5
-5
links.html
h2/src/docsrc/html/links.html
+6
-1
main.html
h2/src/docsrc/html/main.html
+1
-1
mainWeb.html
h2/src/docsrc/html/mainWeb.html
+2
-2
performance.html
h2/src/docsrc/html/performance.html
+7
-10
roadmap.html
h2/src/docsrc/html/roadmap.html
+1
-0
没有找到文件。
h2/src/docsrc/html/history.html
浏览文件 @
d22a1a41
...
...
@@ -50,7 +50,7 @@ http://www.h2database.com/html/roadmap.html
<p>
The development of H2 was started in May 2004,
but it was first published on December 14th 2005.
The author of H2, Thomas Mueller, is also the original developer of Hypersonic SQL.
The
main
author of H2, Thomas Mueller, is also the original developer of Hypersonic SQL.
In 2001, he joined PointBase Inc. where he created PointBase Micro.
At that point, he had to discontinue Hypersonic SQL, but then the HSQLDB Group was formed
to continued to work on the Hypersonic SQL codebase.
...
...
h2/src/docsrc/html/jaqu.html
浏览文件 @
d22a1a41
...
...
@@ -21,7 +21,7 @@ JaQu
<p>
JaQu stands for Java Query and allows to access databases using pure Java.
JaQu provides a fluent interface (or internal DSL) for building SQL statements.
JaQu replaces SQL, JDBC, and
object/relation
frameworks such as Hibernate.
JaQu replaces SQL, JDBC, and
persistence
frameworks such as Hibernate.
JaQu is something like LINQ for Java (LINQ stands for "language integrated query" and is a
Microsoft .NET technology). The following JaQu code:
</p>
...
...
@@ -38,14 +38,14 @@ SELECT * FROM PRODUCTS P
WHERE P.UNITS_IN_STOCK = 0
</pre>
<h2>
Advantages and Differences to
o
ther Data Access Tools
</h2>
<h2>
Advantages and Differences to
O
ther Data Access Tools
</h2>
<p>
Unlike SQL, JaQu can be easily integrated in Java applications. Because JaQu is pure Java,
Javadoc and auto-complete
are supported. Type checking is performed by the compiler.
auto-complete in the IDE and Javadoc and
are supported. Type checking is performed by the compiler.
JaQu fully protects against SQL injection.
</p>
<p>
JaQu is much smaller than
object/relation mapping tool
s such as Hibernate.
JaQu is much smaller than
persistence framework
s such as Hibernate.
Unlike iBatis and Hibernate, no XML or annotation based configuration is required;
instead the configuration (if required at all) is done in pure Java, in the application itself.
</p>
...
...
@@ -56,15 +56,14 @@ JaQu provides full control over when and what SQL statements are executed.
<h3>
Restrictions
</h3>
<p>
Primitive types (eg. boolean, int, long, double) are not supported.
Instead,
Boolean, Integer, Long, and Double
must be use
d.
Primitive types (eg. boolean, int, long, double) are not supported.
Use
Boolean, Integer, Long, and Double
instea
d.
</p>
<h3>
Why in Java?
</h3>
<p>
Most people use Java in their application. Mixing Java and another language (for example Scala or Groovy)
in the same application is complicated. It would be required to split the code to access the database
and the application code.
in the same application is complicated: You would need to split the application and database code.
</p>
<h2>
Current State
</h2>
...
...
@@ -162,7 +161,7 @@ public class Test {
final Product p = new Product();
List
<
ProductPrice> productInfos =
db.from(p).orderBy(p.productId).
select(new ProductPrice() {
{
select(new ProductPrice() {{
productName = p.productName;
category = p.category;
price = p.unitPrice;
...
...
@@ -183,7 +182,7 @@ public class Test {
innerJoin(o).on(c.customerId).is(o.customerId).
where(o.total).smaller(new BigDecimal("500.00")).
orderBy(1).
select(new CustOrder() {
{
select(new CustOrder() {{
customerId = c.customerId;
orderId = o.orderId;
total = o.total;
...
...
@@ -192,7 +191,8 @@ public class Test {
private void testLength() throws Exception {
Product p = new Product();
List
<
Integer> lengths = db.from(p).
List
<
Integer> lengths =
db.from(p).
where(length(p.productName)).smaller(10).
orderBy(1).
selectDistinct(length(p.productName));
...
...
@@ -213,7 +213,7 @@ public class Test {
db.from(p).
groupBy(p.category).
orderBy(1).
select(new ProductGroup() {
{
select(new ProductGroup() {{
category = p.category;
productCount = count();
}});
...
...
@@ -224,7 +224,7 @@ public class Test {
<h2>
Configuration
</h2>
<p>
JaQu does not require any
kind of configuration is you want to use
the default mapping.
JaQu does not require any
configuration when using
the default mapping.
To define table indices, or if you want to map a class to a table with a different name,
or a field to a column with another name, create a function called 'define' in the data class.
Example:
...
...
@@ -243,22 +243,23 @@ public class Product implements Table {
primaryKey(productId);
index(productName, category);
}
}
</pre>
<p>
The method 'define()' contains the mapping definition. It is called once
when the class is used for the first time. Like annotations, the mapping is defined in the class itself.
Unlike when using annotations, the compiler can check the syntax even for multi-column
objects (multi-column indexes, multi-column primary keys and so on).
This solution is very flexible because the definition is written in regular Java code:
Unlike when using annotations, your code can select the right configuration depending
on the environment if required. Unlike XML mapping configuration, the configuration
is integrated in the class itself.
Because the definition is written in regular Java, the configuration can depend on the environment.
This is not possible using annotations.
Unlike XML mapping configuration, the configuration is integrated in the class itself.
</p>
<h2>
Ideas
</h2>
<p>
This project has just been started, and nothing is fixed yet.
Some ideas for what to implement
includ
e:
Some ideas for what to implement
ar
e:
</p>
<ul><li>
Support queries on collections (instead of using a database).
</li><li>
Provide API level compatibility with JPA (so that JaQu can be used as an extension of JPA).
...
...
h2/src/docsrc/html/license.html
浏览文件 @
d22a1a41
...
...
@@ -35,9 +35,9 @@ There is a License FAQ for both the MPL and the EPL, most of that is applicable
<p>
However, nobody is allowed to rename H2, modify it a little, and sell it as a database engine without telling the customers it is in fact H2.
This happened to HSQLDB
, when a
company called 'bungisoft' copied HSQLDB, renamed it to 'RedBase', and tried to sell it,
hiding the fact that it was
, in fact, just HSQLDB. At this time, i
t seems 'bungisoft' does not exist any more, but you can use the
Wayback Machine of http://www.archive.org and
look for
old web pages of http://www.bungisoft.com .
This happened to HSQLDB
: A
company called 'bungisoft' copied HSQLDB, renamed it to 'RedBase', and tried to sell it,
hiding the fact that it was
in fact just HSQLDB. I
t seems 'bungisoft' does not exist any more, but you can use the
Wayback Machine of http://www.archive.org and
visit
old web pages of http://www.bungisoft.com .
</p><p>
About porting the source code to another language (for example C# or C++): Converted source code (even if done manually) stays under the same
copyright and license as the original code. The copyright of the ported source code does not (automatically) go to the person who ported the code.
...
...
@@ -466,8 +466,8 @@ described in <a href="#exhibit-a">Exhibit A</a>.
<h3
id=
"exhibit-a"
>
Exhibit A
</h3>
<pre>
Multiple-Licensed under the H2 License,
Version 1.0,
and under the Eclipse Public License, Version 1.0
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
</pre>
...
...
h2/src/docsrc/html/links.html
浏览文件 @
d22a1a41
...
...
@@ -221,7 +221,7 @@ Java job scheduler, file transfer, workflow, and BPM.
<p><a
href=
"http://ggc.sourceforge.net"
>
GNU Gluco Control
</a><br
/>
Helps you to manage your diabetes.
.
Helps you to manage your diabetes.
</p>
<p><a
href=
"http://www.goldenstudios.or.id"
>
...
...
@@ -409,6 +409,11 @@ OpenGroove</a><br />
OpenGroove is a groupware program that allows users to synchronize data.
</p>
<p><a
href=
"http://code.google.com/p/opensocial-development-environment"
>
OpenSocial Development Environment (OSDE)
</a><br
/>
Development tool for OpenSocial application.
</p>
<p><a
href=
"http://www.orionserver.com"
>
Orion
</a><br
/>
J2EE Application Server.
...
...
h2/src/docsrc/html/main.html
浏览文件 @
d22a1a41
...
...
@@ -17,7 +17,7 @@ H2 Database Engine
<h1>
H2 Database Engine
</h1>
<p>
Welcome to H2, the free SQL database engine.
Welcome to H2, the free
Java
SQL database engine.
</p>
<br
/>
...
...
h2/src/docsrc/html/mainWeb.html
浏览文件 @
d22a1a41
...
...
@@ -22,8 +22,8 @@ H2 Database Engine
Welcome to H2, the Java SQL database. The main feature of H2 are:
</p>
<ul>
<li>
Very fast, open source, JDBC
and ODBC
API
</li><li>
Embedded
, server and clust
er modes; in-memory databases
<li>
Very fast, open source, JDBC API
</li><li>
Embedded
and serv
er modes; in-memory databases
</li><li>
Browser based Console application
</li><li>
Small footprint: around 1 MB jar file size
</li></ul>
...
...
h2/src/docsrc/html/performance.html
浏览文件 @
d22a1a41
...
...
@@ -30,7 +30,7 @@ Performance
<br
/><a
name=
"performance_comparison"
></a>
<h2>
Performance Comparison
</h2>
<p>
In m
ost cases H2 is a lot faster than all
other
In m
any cases H2 is a lot faster than
other
(open source and not open source) database engines.
Please note this is mostly a single connection benchmark run on one computer.
</p>
...
...
@@ -93,7 +93,7 @@ One situation where is H2 is slow is large result sets, because they are buffere
disk if more than a certain number of records are returned.
The advantage of buffering is, there is no limit on the result set size.
The open/close time is almost fixed, because of the file locking protocol: The engine waits
20 ms
after opening a database to ensure the database files are not opened by another process.
some time
after opening a database to ensure the database files are not opened by another process.
</p>
<h4>
HSQLDB
</h4>
...
...
@@ -112,15 +112,15 @@ AND S_W_ID=? AND S_I_ID=OL_I_ID AND S_QUANTITY<?
</pre>
<p>
The PolePosition benchmark also shows that the query optimizer does not do a very good job for some queries.
A
disadvantage in
HSQLDB is the slow startup / shutdown time (currently not listed) when using bigger databases.
The reason is, a backup of the
database is created
whenever the database is opened or closed.
A
nother disadvantage of
HSQLDB is the slow startup / shutdown time (currently not listed) when using bigger databases.
The reason is, a backup of the
whole data is made
whenever the database is opened or closed.
</p>
<h4>
Derby
</h4>
<p>
Version 10.4.2.0 was used for the test. Derby is clearly the slowest embedded database in this test.
This seems to be a structural problem, because all operations are really slow.
It will
not be easy
for the developers of Derby to improve the performance to a reasonable level.
It will
be hard
for the developers of Derby to improve the performance to a reasonable level.
A few problems have been identified: Leaving autocommit on is a problem for Derby.
If it is switched off during the whole test, the results are about 20% better for Derby.
Derby supports a testing mode (system property derby.system.durability=test) where durability is
...
...
@@ -190,7 +190,7 @@ BenchC is similar to the TPC-C test, but single connection / single threaded.
<h4>
Comparing Embedded with Server Databases
</h4>
<p>
This is mainly a benchmark for embedded databases (where the application runs in the same
virtual machine
than
the database engine). However MySQL and PostgreSQL are not Java
virtual machine
as
the database engine). However MySQL and PostgreSQL are not Java
databases and cannot be embedded into a Java application.
For the Java databases, both embedded and server modes are tested.
</p>
...
...
@@ -212,8 +212,7 @@ This benchmark runs three times, but only the last run is measured.
<h4>
Memory Usage
</h4>
<p>
It is not enough to measure the time taken, the memory usage is important as well.
Performance can be improved in databases by using a bigger in-memory cache,
but there is only a limited amount of memory available on the system.
Performance can be improved by using a bigger cache, but the amount of memory is limited.
HSQLDB tables are kept fully in memory by default; this benchmark
uses 'disk based' tables for all databases.
Unfortunately, it is not so easy to calculate the memory usage of PostgreSQL
...
...
@@ -254,8 +253,6 @@ This time is not measured currently.
Also, not tested is the time used to create a database and open an existing database.
Here, one (wrapper) connection is opened at the start,
and for each step a new connection is opened and then closed.
That means the Open/Close time listed is for opening a connection
if the database is already in use.
</p>
<br
/><a
name=
"poleposition_benchmark"
></a>
...
...
h2/src/docsrc/html/roadmap.html
浏览文件 @
d22a1a41
...
...
@@ -408,6 +408,7 @@ Of course, patches are always welcome, but are not always applied as is. Patches
</li><li>
MySQL compatibility: DELETE .. FROM .. USING - See http://dev.mysql.com/doc/refman/5.0/en/delete.html
</li><li>
Allow to scan index backwards starting with a value (to better support ORDER BY DESC).
</li><li>
Java Service Wrapper: try http://yajsw.sourceforge.net/
</li><li>
Batch parameter for INSERT, UPDATE, and DELETE, and commit after each batch. See also MySQL DELETE.
</li></ul>
<h2>
Not Planned
</h2>
...
...
编写
预览
Markdown
格式
0%
重试
或
添加新文件
添加附件
取消
您添加了
0
人
到此讨论。请谨慎行事。
请先完成此评论的编辑!
取消
请
注册
或者
登录
后发表评论