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�E�序员修水管

a_alter — Mon, 29 Oct 2012 06:04:00 GMT

一�E�序员家的水��坏了，他打电话叫来一个水��工修理�?nbsp;水管工鼓捣了一个小�Ӟ��l�于把管子修好了�Q�他递给�E�序员一�?00元的帐单�?nbsp;“600元！”�E�序员愤怒地��_��“我当�E�序员一天都赚不了这么多钱！” “是啊�?#8221;水管工��^静地��_��“我当�E�序员的时候也是�?#8221;

a_alter 2012-10-29 14:04 发表评论

Oracle LEFT JOIN 多层�U�问�?

a_alter — Tue, 09 Oct 2012 02:15:00 GMT

�? 如下
�? A
(1--->n) 表B (B 可能为空)
(n---->n)表C

(n---->n)表D

现在有如下问�? 在查询的时候我们允许b为空的A数据
Select * from A,B where A.B_AID = B.AID(+)

扩展查询如果�q�行B兌��C�U�别的条件过�?br />

Select * from A,B, C where A.B_AID = B.AID(+) and B.C_AID = C.AID;

�q�个时候C能够知道B是可以�ؓ�I�的�Q?�q�个时候的join效果是，如果在A兌��B B存在的情况下在��?C的join 条�g�q�行�{�选�?�q�个时候B为空的A条�g�q�是可以摆查出来的�?只不�q�数据列B为空而已

再进行扩展筛�? �q�行C兌��D�U�别的条�{��?/span>

Select * from A,B,C,D where A.B_AID = B.AID(+) and B.C_AID = C.AID and C.D_AID = D.AID;

�q�样的D�U�别的筛选就会破坏B�U�别的赛选�?/div>�q�个时候测试效果就�?D �U�别的join条�g 会破�?B的left join 效果�?br />
你可能想到改写条件如�?br />Select * from A,B,C,D where A.B_AID = B.AID(+) and B.C_AID = C.AID and C.D_AID(+) = D.AID;

可惜我测试结果和full join 的效果是一��L��Q�不是oracle高手�Q?谁知道的留个�a�火链�? 谢谢

=======================================================================
后来扑֐�学帮�? 得知他以前也遇到�q�情�?br />改写为如下条�?br />

select * from (Select ....,C.D_AID from A,B,C where A.B_AID = B.AID(+) and B.C_AID = C.AID ) E,D where E.D_AID(+) = D.AID
�q�样��׃��会破坏B(+) 效果�?

个�h理解��是 select 的组�l�数据效果。具体不清楚 �Ƣ迎发言�?/div>
=======================================================================
补充�Q?br />今天我才知道 left join �?inner join 栏位是否必填�q�有关系�?br />
在这个问题上有个地方被欺骗了

��是�?A Left join B inner JOIN C 的时�? 如果 B �?C 字段是必填的�? 那么��q��当于 left join�?如果不是必填的话你必��L��动的指示 left join (+) �?br />=====================================================================
补充 2012/10/19 发现以上的理解不全面

A--B(+) 意思指B 端可为空�Q?如果对B -- C 下面的元素进行赛选，在局部看 B �?C 的关�p�L��两段都必��d��在的�Q?但是在A -- B(+) 的前提下 C可以为空�? 所以需要��?B --- C(+) 来进行关�?nbsp; �q�样的坏处是可能会加载出 B (存在)-- C (不存�? �q�样的错误数据�?当然如果�pȝ��中有对这�U�数据有��实保障的时候可以忽略该问题

如果没有��切的保障的�?
可能��需要��?A --- D(+) 其中D �?nbsp; select * from B,C where B = C �q�样的过滤方式，但是�q�样��增加了复杂度，你需要将可能用到的查询条件和查询�l�果集在D�?select 一一列出�?

�?Select A.*,R1,R2,R3 from A ,(select B.A_Aid,c1,c2,c3,R1,R2,R3 from B,C where B.C_AID= C.Aid) D where A.Aid = B.A_Aid and c1 = ? and c2 = ? ....

Sql 复杂度高了一炏V�?br />

a_alter 2012-10-09 10:15 发表评论

Oracle sql 写法

a_alter — Wed, 12 Sep 2012 04:57:00 GMT

本文用途：因�ؓ暂时没有旉��d��体看oracle sql的官�Ҏ��?�Q�纪录oracle的一些特�D�写法�?(不断更新)

1. with ... as ...

with querya as (select * from TB_Test)

2 case .. (when .. then) .... (when .. then) .. else ... end

SELECT FO_FULFILL_TRX_STRING.SEQUENCE_NO, AC_TYPE_ORDER.CODE, CASE

WHEN AC_TYPE_ORDER.CODE = 'SO'

THEN ( SELECT ORDER_NUMBER FROM SO_ORDER WHERE SO_ORDER.AID = FO_FULFILL_TRX_STRING.AID_ORDER_SO )

ELSE ( SELECT ORDER_NUMBER FROM PO_ORDER WHERE PO_ORDER.AID = FO_FULFILL_TRX_STRING.AID_ORDER_PO )

END ORDER_NUMBER

FROM FO_FULFILL_TRX_STRING, AC_TYPE_ORDER.CODE

------------------------------------------------------------------------------------------------------------------------------

MYSQL 正则支持

select * from tb_rule_list where expression regexp '^.*\\$\\{0}\\[3].*$';

Oracle 正则函数支持

ORACLE中的支持正则表达式的函数主要�?/div>

REGEXP_LIKE �Q�与LIKE的功能相�?/div>

REGEXP_INSTR �Q�与INSTR的功能相�?/div>

REGEXP_SUBSTR �Q�与SUBSTR的功能相�?/div>

REGEXP_REPLACE �Q�与REPLACE的功能相

------------------------------------------------------------------------------------------------------------------------------

在MYSQL �?select 可以昄�� 不是group by 中的分组字段�Q?可以是�Q意的数据列，具体数据昄��的是分组后的�W�一行数�?/div>

在ORACLE�?select 是严格的只能昄��group by 中的字段�?/div>

同样效果的两行sql --- 让自己注意提高自��q��使用灉|��?/div>

1. select a.aid AAid,nvl(b.cot,0) countline from po_draft_order a,(select AID_DRAFT_ORDER_PO BAID,count(*) cot from po_draft_line group by AID_DRAFT_ORDER_PO) b WHERE A.AID = B.BAID(+);

2. select a.aid, (select count(*) from po_draft_line where AID_DRAFT_ORDER_PO = a.aid ) c from po_draft_order a;

-------------------------------------------------------------------------------------------------------------------------------

oracle 分��

rank()/dense_rank() over(partition by ... order by ...) 加强对分�l�排序之后的数据的控制力�?/div>

over: over(...)

partition by : 相当于group by

order by e.sal desc: 按工资从高到低排序（使用rank()/dense_rank() �Ӟ��必须要带order by否则非法�Q?/div>

rank()/dense_rank(): 分��

整个语句的意思就是：在按部门划分的基��上，按工资从高到低对雇员�q�行分��Q?#8220;�U�别”�׃��到大的数字表示�Q�最��g��定�ؓ1�Q��?nbsp;

那么rank()和dense_rank()有什么区别呢�Q?/div>

rank(): 跌��排序�Q�如果有两个�W�一�U�时�Q�接下来��是�W�三�U��?/div>

dense_rank(): �q�箋排序�Q�如果有两个�W�一�U�时�Q�接下来仍然是第二��?/div>

min()/max() over(partition by ...) // 分组最大最��?/div>

lead()/lag() over(partition by order by) // 前后数据比较使用

lead(列名,n,m): 当前记录后面�W�n行记录的<列名>的��|��没有则默认��gؓm�Q�如果不带参数n,m�Q�则查找当前记录后面�W�一行的记录<列名>的��|��没有则默认��gؓnull�?/div>

lag(列名,n,m): 当前记录前面�W�n行记录的<列名>的��|��没有则默认��gؓm�Q�如果不带参数n,m�Q�则查找当前记录前面�W�一行的记录<列名>的��|��没有则默认��gؓnull�?/div>

主要是各个函数和over的配合��用�?/div>

-----------------------------------------------------------------------------------------------------------------------------------------------------

Oracle 的集合运��?/div>

UNION 用来合�ƈ�l�果�?要求�q�回字段是一��L��?/div>

JOIN 用来合�ƈ字段�?/div>

�q��

UNION ALL, FULL JOIN -- 重复出现

UNION, INNER JOIN minus -- 一�ơ出�?/div>

交集

intersect

差集

minus

�W�卡��积

CROSS JOIN
------------------------------------------------------------------------------------------------------------------------------
INNER JOIN oracle �Ҏ��的写�?不知道在sqlserver 是否支持�?br />

SELECT
*
FROM (
SO_WEC_SODL_DESPATCH_HEADER AS SO_WEC_SODL_DESPATCH_HEADER_1
    INNER JOIN (
      (
        SO_WARRANTY_ENTITLEMENT WET_1
        INNER JOIN (SO_WARRANTY_ENTITLEMENT INNER JOIN SO_WEC_SODL
        ON SO_WARRANTY_ENTITLEMENT.AID = SO_WEC_SODL.AID_WARRANTY_ENTITLEMENT_SO
        ) ON (WET_1.AID_COMPANY = SO_WARRANTY_ENTITLEMENT.AID_COMPANY)
        AND (WET_1.SEQ_ITEM_NUM = SO_WARRANTY_ENTITLEMENT.PARENT_SEQ_ITEM)
        AND (WET_1.ITEM_LINE_NUM = SO_WARRANTY_ENTITLEMENT.PARENT_ITEM_NUM)
        AND (WET_1.SO_LINE_NUM = SO_WARRANTY_ENTITLEMENT.PARENT_SOLINE_NUM)
        AND (WET_1.SO_NUM = SO_WARRANTY_ENTITLEMENT.SO_NUM)
      )
      INNER JOIN SO_WEC_SODL AS SO_WEC_SODL_1 ON (SO_WEC_SODL.LINE_DELIVERY_NUMBER = SO_WEC_SODL_1.LINE_DELIVERY_NUMBER)
      AND (WET_1.AID = SO_WEC_SODL_1.AID_WARRANTY_ENTITLEMENT)
    ) ON SO_WEC_SODL_DESPATCH_HEADER_1.AID_WEC_SODL = SO_WEC_SODL_1.AID
) INNER JOIN SO_WEC_SODL_DESPATCH_HEADER ON SO_WEC_SODL.AID = SO_WEC_SODL_DESPATCH_HEADER.AID_WEC_SODL

===

a_alter 2012-09-12 12:57 发表评论

a_alter — Mon, 10 Sep 2012 09:20:00 GMT

今天看Richface4.2文档的时�?发现变动很大 �U�录�?br />

3.1. Full technical requirements

RichFaces has been developed with an open architecture to be compatible with a wide variety of environments.

3.1.1. Server requirements

RichFaces 4 requires either of the following server technologies:

An application server compliant with Java Platform, Enterprise Edition 6 (JEE6 or JEE6), such as JBoss Application Server 7.
A major servlet container, such as Jetty 8 or Apache Tomcat 7. (看到�q�个只能对自��q��TOMCAT 6 望望�Q?7 �q�支�?Servlet3.0 规范�Q�不知道现在支持servlet3.0 的框架有哪些 �q�没注意一直用2.5)

3.1.2. Client requirements

Clients accessing RichFaces applications require a web browser. RichFaces supports the following web browsers:

Linux environments

Firefox 3.6 or Firefox 7.0 and higher
Google Chrome 14 and higher

Mac OS environments

Safari 5.1 and higher

Microsoft Windows environments

Firefox 3.6 or Firefox 7.0 and higher
Google Chrome 14 and higher
Internet Explorer 8.0 and higher �q�个中国的用��L��是要注意�?/span> 如果需要支持IE6+ 只能使用richface3.3.

Other browsers and versions are partially supported.

3.1.3. Development requirements

Developing applications with the RichFaces framework requires the Java Development Kit (JDK), an implementation of JavaServer Faces (JSF), and a development environment.

Java Development Kit (JDK)

RichFaces supports the following JDK versions:

JDK 1.6 and higher JDK1.5 的用户只能望望了

JavaServer Faces (JSF)

RichFaces supports the following JSF implementations and frameworks:

MyFaces 2.x
Seam 3.x 2.* 的seam �q�是byebye
Mojara 2.x

Development environment

RichFaces can be developed using most Java development environments. The following are recommended, and used for examples in this guide:

JBoss Tools 3.3 and higher (�q�个肯跌�Q�连带Eclipse的版本都要更斎ͼ�需�?.7 如果没记错的话， �q�有webtool)
Maven 3.0.3 and higher

a_alter 2012-09-10 17:20 发表评论

a_alter — Fri, 07 Sep 2012 06:30:00 GMT

在Eclipse �~�辑器中加入xmln 提示功能支持

是针寚w��目设定的�Q?叛_��目选择 Properties --�?Project Facets ��N��你需要��用的 schema定义�?img src ="http://www.tkk7.com/alter/aggbug/387247.html" width = "1" height = "1" />

a_alter 2012-09-07 14:30 发表评论

seam ��单介�l?

a_alter — Thu, 30 Aug 2012 01:38:00 GMT

前序

用了seam也快一�q�了�Q?可惜一直是在做开发，今天军_��回头�ȝ��下， �q�且�ȝ��一下JSF �Q?SEAM 的配�|��?

seam ��单介�l?br />
直接看英文吧, ��译的不�?br />

Seam is a powerful open source development platform for building rich Internet applications in Java. Seam integrates technologies such as Asynchronous JavaScript and XML (AJAX), JavaServer Faces (JSF), Java Persistence (JPA), Enterprise Java Beans (EJB 3.0) and Business Process Management (BPM) into a unified full-stack solution, complete with sophisticated tooling.

Seam has been designed from the ground up to eliminate complexity at both architecture and API levels. It enables developers to assemble complex web applications using simple annotated Java classes, a rich set of UI components, and very little XML. Seam's unique support for conversations and declarative state management can introduce a more sophisticated user experience while at the same time eliminating common bugs found in traditional web applications.

我们可以看到seam �?jsf,jpa,ejb �l�合比较紧密�Q�提供了annotation 方式支持�Q?提供了大量的 ui components 支持�?br />

惌��的一�Ҏ��Q?seam不是一个框�Ӟ�� 而是一个��^台�?br />

附：
JSF 资料查询 http://caterpillar.onlyfun.net/Gossip/JSF/IntroduceJSF.htm

http://docs.oracle.com/javaee/5/tutorial/doc/bnaph.html

==== seam 提供了一个定制的eclipse版本用于seam开发，省了很多�?br />
https://devstudio.jboss.com/earlyaccess/

a_alter 2012-08-30 09:38 发表评论