main表
id    test_id    salary       
1     1         Null      
2     1         Null       
3     2          Null           

请用test表中的salary更新main表中的salary
看到这题目让我傻了，这么简单的题目，可我就是不会。

下面是我回来后重新查帮助后才解决的。测试数据如下，
create table test(
  id int primary key identity(1,1),
  salary int
)
go
insert into test(salary) values(100)
insert into test(salary) values(200)
go
create table main(
  id int primary key identity(1,1),
  test_id int references test(id),
  salary int
)
go
insert into main(test_id) values(1)
insert into main(test_id) values(2)
go

答案：
UPDATE main
SET main.salary = test.salary
FROM main INNER JOIN test ON (test.id =main.test_id)

总结：update 还可以和 from 一起用，自己真的是孤陋寡闻。

lazy=true 一句查询 有getPicture()
Hibernate: select photos0_.id as id0_0_, photos0_.userid as userid0_0_, photos0_.typeid as typeid0_0_, photos0_.name as name0_0_, photos0_.createtime as createtime0_0_, photos0_.description as descript6_0_0_, photos0_.faceid as faceid0_0_, photos0_.uri as uri0_0_ from super.photos photos0_ where photos0_.id=?

lazy=true 一句查询  有getPicture() 并且访问了里面的元数Picture 且有异常抛出
Hibernate: select photos0_.id as id0_0_, photos0_.userid as userid0_0_, photos0_.typeid as typeid0_0_, photos0_.name as name0_0_, photos0_.createtime as createtime0_0_, photos0_.description as descript6_0_0_, photos0_.faceid as faceid0_0_, photos0_.uri as uri0_0_ from super.photos photos0_ where photos0_.id=?

lazy="false" 两句查询  肯定没问题，因为全部数据都个查了出来 所以怎么调用都正常
Hibernate: select photos0_.id as id0_0_, photos0_.userid as userid0_0_, photos0_.typeid as typeid0_0_, photos0_.name as name0_0_, photos0_.createtime as createtime0_0_, photos0_.description as descript6_0_0_, photos0_.faceid as faceid0_0_, photos0_.uri as uri0_0_ from super.photos photos0_ where photos0_.id=?
Hibernate: select pictures0_.photosid as photosid1_, pictures0_.id as id1_, pictures0_.id as id2_0_, pictures0_.photosid as photosid2_0_, pictures0_.name as name2_0_, pictures0_.clicked as clicked2_0_, pictures0_.uploaddate as uploaddate2_0_, pictures0_.size as size2_0_, pictures0_.description as descript7_2_0_, pictures0_.uri as uri2_0_ from super.picture pictures0_ where pictures0_.photosid=?

fetch="join"  一句查询  效果 ＝＝ lazy="false" 呵呵，哪个效率高，我就不知道了。。。。。。。。。。。
Hibernate: select photos0_.id as id0_1_, photos0_.userid as userid0_1_, photos0_.typeid as typeid0_1_, photos0_.name as name0_1_, photos0_.createtime as createtime0_1_, photos0_.description as descript6_0_1_, photos0_.faceid as faceid0_1_, photos0_.uri as uri0_1_, pictures1_.photosid as photosid3_, pictures1_.id as id3_, pictures1_.id as id2_0_, pictures1_.photosid as photosid2_0_, pictures1_.name as name2_0_, pictures1_.clicked as clicked2_0_, pictures1_.uploaddate as uploaddate2_0_, pictures1_.size as size2_0_, pictures1_.description as descript7_2_0_, pictures1_.uri as uri2_0_ from super.photos photos0_ left outer join super.picture pictures1_ on photos0_.id=pictures1_.photosid where photos0_.id=?

不加fetch＝"join" 一句查询  没有getPicture() 正常
Hibernate: select photos0_.id as id0_0_, photos0_.userid as userid0_0_, photos0_.typeid as typeid0_0_, photos0_.name as name0_0_, photos0_.createtime as createtime0_0_, photos0_.description as descript6_0_0_, photos0_.faceid as faceid0_0_, photos0_.uri as uri0_0_ from super.photos photos0_ where photos0_.id=?

不加fetch＝"join" 一句查询  有getPicture() 正常
Hibernate: select photos0_.id as id0_0_, photos0_.userid as userid0_0_, photos0_.typeid as typeid0_0_, photos0_.name as name0_0_, photos0_.createtime as createtime0_0_, photos0_.description as descript6_0_0_, photos0_.faceid as faceid0_0_, photos0_.uri as uri0_0_ from super.photos photos0_ where photos0_.id=?

不加fetch＝"join" 一句查询 有getPicture() 并且访问里面的元素Picture的ID 有异常抛出
Hibernate: select photos0_.id as id0_0_, photos0_.userid as userid0_0_, photos0_.typeid as typeid0_0_, photos0_.name as name0_0_, photos0_.createtime as createtime0_0_, photos0_.description as descript6_0_0_, photos0_.faceid as faceid0_0_, photos0_.uri as uri0_0_ from super.photos photos0_ where photos0_.id=?

来个两兵交战 fetch="join" lazy="true"  呵呵 结果，一句查询， 结构正常 所以就当lazy不存在好了。 看来fetch 是老大。、、、、、、、、、、、、、
Hibernate: select photos0_.id as id0_1_, photos0_.userid as userid0_1_, photos0_.typeid as typeid0_1_, photos0_.name as name0_1_, photos0_.createtime as createtime0_1_, photos0_.description as descript6_0_1_, photos0_.faceid as faceid0_1_, photos0_.uri as uri0_1_, pictures1_.photosid as photosid3_, pictures1_.id as id3_, pictures1_.id as id2_0_, pictures1_.photosid as photosid2_0_, pictures1_.name as name2_0_, pictures1_.clicked as clicked2_0_, pictures1_.uploaddate as uploaddate2_0_, pictures1_.size as size2_0_, pictures1_.description as descript7_2_0_, pictures1_.uri as uri2_0_ from super.photos photos0_ left outer join super.picture pictures1_ on photos0_.id=pictures1_.photosid where photos0_.id=?

<iframe width="145" height="130" border="0" align="center" marginwidth="0" marginheight="0" hspace="0" vspace="0" frameborder="0" scrolling="no" src="http://minisite.qq.com/Weather/news_new.html" allowTransparency="true"></iframe>
<br><br><br><br>

<iframe ALIGN='center' src="http://weather.265.com/weather.htm" width="168" height="54" frameborder="no" border="0" marginwidth="0" marginheight="0" scrolling="no"></iframe>
<br><br><br><br>

<IFRAME ID='ifm1' WIDTH='405' HEIGHT='332' ALIGN='center' MARGINWIDTH='0' MARGINHEIGHT='0' HSPACE='0' VSPACE='0' FRAMEBORDER='0' SCROLLING='NO' SRC="http://weather.qq.com/24.htm"></IFRAME>
<br><br><br>

<iframe width=160 height=230 frameborder=0 ALIGN='center' scrolling=NO src=http://appnews.qq.com/cgi-bin/news_qq_search?city=广州></iframe>
<br><br><br>

<iframe width="469" height="218" border="0" align="center" marginwidth="0" marginheight="0" hspace="0" vspace="0" frameborder="0" scrolling="no" src="http://appnews.qq.com/cgi-bin/news_weather_search?city=广州" allowTransparency="true"></iframe>
<br><br>
<IFRAME ID='ifm1' WIDTH='260' HEIGHT='70' ALIGN='CENTER' MARGINWIDTH='0' MARGINHEIGHT='0' HSPACE='0' VSPACE='0' FRAMEBORDER='0' SCROLLING='NO' src="http://news.sina.com.cn/iframe/weather/440101.html"></iframe>

效果如下：

The open source JasperReports uses XML templates for your reporting needs

Summary
JasperReports, a popular, full-featured open source report-generating library, uses XML report templates to generate reports you can display on the screen, send to a printer, or save as a PDF document. In this inaugural Open Source Profile column, Erik Swenson introduces the JasperReports library and explains how to integrate JasperReports into your applications. (900 words;September 20, 2002)

By Erik Swenson

enerating reports is a common, if not always glamorous, task for programmers. In the past, report generation has largely been the domain of large commercial products such as Crystal Reports. Today, the open source JasperReports report generating library gives Java developers a viable alternative to commercial software.

JasperReports provides the necessary features to generate dynamic reports, including data retrieval using JDBC (Java Database Connectivity), as well as support for parameters, expressions, variables, and groups. JasperReports also includes advanced features, such as custom data sources, scriptlets, and subreports. All in all, JasperReports combines good features, maturity, community participation, and, best of all, it's free.

This article kicks off JavaWorld's new Open Source Profile column dedicated to Java-based open source tools and components. Look for upcoming articles spotlighting the Echo Web application framework and ObJectRelationalBridge, an object/relational mapping tool. Feel free to send me your suggestions for future articles.

Note: The documentation and code featured in this article are based on JasperReports version 0.3.3.

Report design
In JasperReports, you design reports using XML report templates. For example, the following XML file is a template for a report with a title, two columns of data, and page numbers:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jasperReport PUBLIC "-//JasperReports//DTD Report Design//EN"
"http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">
<jasperReport name="BasicReport" >
  <parameter name="Title" class="java.lang.String"/>
  <queryString><![CDATA[select name, cost from product]]></queryString>
  <field name="NAME" class="java.lang.String"/>
  <field name="COST" class="java.lang.Double"/>
  <title>
    <band height="50">
      <textField>
        <reportElement x="0" y="0" width="200" height="50" />      
        <textFieldExpression class="java.lang.String">$P{Title}</textFieldExpression>
      </textField>
    </band>
  </title>
  <pageHeader>
    <band>
    </band>
  </pageHeader>
  <columnHeader>
    <band height="20">
      <staticText>
        <reportElement x="180" y="0" width="180" height="20"/>
        <textElement>
          <font isUnderline="true"/>
        </textElement>
        <text><![CDATA[NAME]]></text>
      </staticText>
      <staticText>
        <reportElement x="360" y="0" width="180" height="20"/>
        <textElement>
          <font isUnderline="true"/>
        </textElement>
        <text><![CDATA[COST]]></text>
      </staticText>
    </band>
  </columnHeader>
  <detail>
    <band height="20">
      <textField>
        <reportElement x="180" y="0" width="180" height="20"/>

  
        <textFieldExpression class="java.lang.String"><![CDATA[$F{NAME}]]></textFieldExpression>
      </textField>
      <textField pattern="0.00">
        <reportElement x="360" y="0" width="180" height="20"/>

  
        <textFieldExpression class="java.lang.Double"><![CDATA[$F{COST}]]></textFieldExpression>
      </textField>
    </band>
  </detail>
  <columnFooter>
    <band>
    </band>
  </columnFooter>
  <pageFooter>
    <band height="15">
      <staticText>
        <reportElement x="0" y="0" width="40" height="15"/>
        <textElement/>
        <text><![CDATA[Page:]]></text>
      </staticText>
      <textField>
        <reportElement x="40" y="0" width="100" height="15"/>
        <textElement/>
        <textFieldExpression class="java.lang.Integer"><![CDATA[$V{PAGE_NUMBER}]]></textFieldExpression>
      </textField>
    </band>
  </pageFooter>
  <summary>
    <band>
    </band>
  </summary>
</jasperReport>


The template's beginning includes any parameters passed into the report, the query that retrieves the data for the report, and the fields displayed in the report. The template's remainder divides into six report sections:

• title
• pageHeader
• columnHeader
• detail
• columnFooter
• pageFooter
• summary

   

Each report section, called a band, is given a height. Each band can include multiple staticText and textField elements, which are given a position, size, and value. Report parameters, fields, and variables are referenced using P${name}, F${name}, and V${name}, respectively.

For example, the following lines in the page footer section create a textField containing the current page number. The page number's value is set to the variable PAGE_NUMBER, defined internally by JasperReports and available to all reports:

<textField>
  <reportElement x="40" y="0" width="100" height="15"/>
  <textElement/>
  <textFieldExpression class="java.lang.Integer"><![CDATA[$V{PAGE_NUMBER}]]></textFieldExpression>
</textField>


The above template represents a basic, yet functional, report. A thorough JasperReports XML-template description is beyond the scope of this article, but I've included numerous links in Resources to tools that will help you edit and create your own report templates. Next, let's see how to use JasperReports in your Java applications.

Use JasperReports
To begin using JasperReports, you first must understand what objects JasperReports uses to represent the reporting process as it progresses from report design to report generation:

• JasperDesign: Represents a report's definition. In most cases, you create a JasperDesign from an XML report template, though you can also create it programmatically.

   

• JasperReport: Represents a compiled JasperDesign. The compilation process verifies the report design and compiles the design into a JasperReport object.

   

• JasperPrint: Represents a generated report. You create a JasperPrint from a JasperReport through the fill process in which a report is populated with data from a data source.

   

The JasperReports API's flexibility lets you load JasperDesign, JasperReport, and JasperPrint objects from a file or a stream, and also lets you create these objects programmatically. You can print reports to a printer, an image, or a PDF file. The JasperReports library includes a facade class, dori.jasper.engine.JasperManager, with methods that facilitate loading, compiling, filling, and printing reports. The following code illustrates a JasperManager:

// First, load JasperDesign from XML and compile it into JasperReport
JasperDesign jasperDesign = JasperManager.loadXmlDesign("BasicReport.xml");
JasperReport jasperReport = JasperManager.compileReport(jasperDesign);

// Second, create a map of parameters to pass to the report.
Map parameters = new HashMap();
parameters.put("ReportTitle", "Basic JasperReport");
parameters.put("MaxSalary", new Double(25000.00));

// Third, get a database connection
Connection conn = Database.getConnection();

// Fourth, create JasperPrint using fillReport() method
JasperPrint jasperPrint = JasperManager.fillReport(jasperReport,
   parameters, conn);

// You can use JasperPrint to create PDF
JasperManager.printReportToPdfFile(jasperPrint, "BasicReport.pdf");

// Or to view report in the JasperViewer
JasperViewer.viewReport(jasperPrint);


The code example above shows how to perform some common tasks using JasperReports. In a real-world application, you'd find it impractical to load and compile the JasperDesign every time you wanted to generate a report. Since report designs are largely static, in most cases, you'd precompile your JasperDesign files to increase speed. You can also increase a large report's speed by generating and saving JasperPrint objects as part of a nightly batch process.

That's all you need to get started; download JasperReports and you'll be up and running in no time.

Reports the easy way
In this article, you learned how the open source JasperReports can aid your Java reporting needs. If you are building a reporting application or looking to add reporting capability to an existing application, look at JasperReports. Visit the JasperReports homepage for more information and download the latest version.

对jsf项目的支持，sun creator 无疑给人一种 耳目一新的感觉：
他对可视化开发的支持真的开始可以和.Net较劲了。

但是 creator 有个问题就是可以把项目部署到 sun app server的项目部署到其他服务器老是出同样的问题：
 
下面总结一下：

步骤一:  把项目导出成 *.war文件
步骤二:  把*.war拷贝到其他服务器的部署目录
         比如 tomcat/resin 的 webapp下
步骤三:  运行服务器(tomcat/resin) 问题来了,出现异常
[10:41:34.828] java.lang.NullPointerException
[10:41:34.828]  at javax.faces.webapp.FacesServlet.init(FacesServlet.java:144)
[10:41:34.828]  at com.caucho.server.dispatch.ServletConfigImpl.createServletImpl(ServletConfigImpl.java:646)
[10:41:34.828]  at com.caucho.server.dispatch.ServletConfigImpl.createServlet(ServletConfigImpl.java:587)

看到这个"FacesServlet.java:144" 开始我怀疑是sun 的包的问题, 网上google和baidu了一下,没搜到相关问题的解决办法.
    最后在一个朋友的帮助下在web.xml文件里加了个Listener:
      <listener>
        <listener-class>com.sun.faces.config.ConfigureListener</listener-class>
     </listener>
嘿,还真行.

心得如下:
     在用workshop或者myeclipse用myfaces包建jsf项目时,我们不会碰到类似的问题.
因为工具已经在web.xml里面加了listener:
 <listener>
  <!-- Listener, that does all the startup work (configuration, init). -->
  <listener-class>org.apache.myfaces.webapp.StartupServletContextListener    </listener-class>
 </listener>
但是如果用这些工具用 sun jsf 包时就要手动listerner.(如:步骤三)

给大家个连接: sun creator的教程,从这里开始学jsf感觉比较全面:
http://gceclub.sun.com.cn/prodtech/javatools/jscreator/learning/tutorials/index.html

insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')

create table review(
  id int primary key identity(1,1),
  topicid int references topic(id),
  content text,
  posttime datetime default getdate()
)

insert into review(topicid,content) values(1,'reice1')
insert into review(topicid,content) values(1,'reice1')
insert into review(topicid,content) values(2,'reice1')
insert into review(topicid,content) values(2,'reice1')
insert into review(topicid,content) values(2,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(4,'reice1')

select t.id,t.title,t.content,r.newposttime from topic as t inner join (select max(posttime) as newposttime, topicid from review group by topicid) as r on t.id=r.topicid

这些是测试数据,sqlserver2000测试通过

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