it-e-33 PostgreSQL

PostgreSQL is an object-relational database management system (ORDBMS) based on
POSTGRES, Version 4.2, developed at the University of California at Berkeley Computer
Science Department. POSTGRES pioneered many concepts that only became available in some
commercial database systems much later.
Features PostgreSQL is an open-source descendant of this original Berkeley code. It
supports SQL92 and SQL99 and offers many modern features:
complex queries
foreign keys
transactional integrity
multiversion concurrency control
Additionally, PostgreSQL can be extended by the user in many ways, for exampleby
adding new

data types
aggregate functions
index methods
procedural languages
And because of the liberal license, PostgreSQL can be used, modified, and distributed by
everyone free of charge for any purpose, be it private, commercial, or academic.

Advantages PostgreSQL offers many advantages for your company or business over other
database systems.
1) Immunity to over-deployment
Over-deployment is what some proprietary database vendors regard as their #1 licence
compliance problem. With PostgreSQL, no-one can sue you for breaking licensing agreements,
as there is no associated licensing cost for the software.
This has several additional advantages:
More profitable business models with wide-scale deployment.
No possibility of being audited for license compliance at any stage.
Flexibility to do concept research and trial deployments without needing to include
additional licensing costs.
2) Better support than the proprietary vendors
In addition to our strong support offerings, we have a vibrant community of PostgreSQL
professionals and enthusiasts that your staff can draw upon and contribute to.
3) Significant saving on staffing costs
Our software has been designed and created to have much lower maintenance and tuning
requirements than the leading proprietary databases, yet still retain all of the features, stability,
and performance.
In addition to this our training programs are generally regarded as being far more cost
effective, manageable, and practical in the real world than that of the leading proprietary database
4) Legendary reliability and stability
Unlike many proprietary databases, it is extremely common for companies to report that
PostgreSQL has never, ever crashed for them in several years of high activity operation. Not
even once. It just works.
5) Extensible
The source code is available to all at no charge. If your staff have a need to customise or
extend PostgreSQL in any way then they are able to do so with a minimum of effort, and with no
attached costs. This is complemented by the community of PostgreSQL professionals and
enthusiasts around the globe that also actively extend PostgreSQL on a daily basis.
6) Cross platform
PostgreSQL is available for almost every brand of Unix (34 platforms with the latest stable
release), and Windows compatibility is available via the Cygwin framework. Native Windows
compatibility is also available with version 8.0 and above.
7) Designed for high volume environments
We use a multiple row data storage strategy called MVCC to make PostgreSQL extremely
responsive in high volume environments. The leading proprietary database vendor uses this
technology as well, for the same reasons.
8) GUI database design and administration tools

Several high quality GUI tools exist to both administer the database (pgAdmin, pgAccess)
and do database design (Tora, Data Architect).


1, teller  ['telə]
n. (美)出纳员;讲述者;讲故事者;计票员

2, reservation  [,rezə'veiʃən]
n. 预约,预订;保留
3, at will 
4, pioneer  [,paiə'niə]
n. 先锋;拓荒者
vt. 开辟;倡导;提倡
vi. 作先驱

5, proprietary  [prə'praiətəri]
a. 专利的(所有的)
n. 所有权(所有人)

6, globe  [gləub]
n. 地球,地球仪,球体

7, volume  ['vɔlju:m; (US) -jəm]
n. 体积,容量,音量
n. 卷,册

Continue reading it-e-33 PostgreSQL

mongoDB 笔记


java driver下载:





mongod --port 13668 --logpath D:/mongodb-win32-i386-1.8.1/log/mongo.log --logappend --dbpath D:/mongodb-win32-i386-1.8.1/data --directoryperdb --serviceName MongoDb_181 –install

注意建议不要使用参数 --bind_ip ,这样的话只能通过127.0.0.1来连接,使用局域网ip和localhost则不能连上


mongod --serviceName MongoDb_181  --remove

如果不需要作为服务,去掉上面的命令中的—install 和 --serviceName  参数即可


mongod  --port 13668 --logpath D:/mongodb-win32-i386-1.8.1/log/mongo.log --logappend --dbpath D:/mongodb-win32-i386-1.8.1/data –directoryperdb


--logpath 参数必须是个文件,不能是文件夹

--dbpath 所指向的文件夹必须已经存在,否则安装成功却启动不了,总是重复启动--失败


更多命令参数见    --help










对应的客户端命令则是mongo --port 13668



use 命令可切换到指定数据库,不存在的话就会创建一个,但不是马上创建,而是在插入数据时创建。






使用java 见

它的依赖很简单,只要添加驱动依赖包就可以say hello world!了:

>public class HelloWorls { public HelloWorls() { } public static void main(String[] args) { try { Mongo m = new Mongo( "192.168.666.666" , 13668 );

Continue reading mongoDB 笔记

it-e-32 Introduction to DBMS

A database management system (DBMS) is an important type of programming system, used
today on the biggest and the smallest computers. [1]As for other major forms of system software,
such as compilers and operating systems, a well-understood set of principles for database
management systems has developed over the years, and these concepts are useful both for
understanding how to use these systems effectively and for designing and implementing DBMS's.
DBMS is a collection of programs that enables you to store, modify, and extract information
from a database. There are many different types of DBMS's, ranging from small systems that run
on personal computers to huge systems that run on mainframes. The following are the location of
database between application programs and end-users.

There are two qualities that distinguish database management systems from other sorts of
programming systems.
1) The ability to manage persistent data, and
2) The ability to access large amounts of data efficiently.

Point 1) merely states that there is a database which exists permanently; the contents of this
database is the data that a DBMS accesses and manages.

Point 2) distinguishes a DBMS from a
file system, which also manages persistent data. A DBMS's capabilities are needed most when
the amount of data is very large, because for small amounts of data, simple access techniques,
such as linear scans of the data, are usually adequate.
[2]While we regard the above two properties of a DBMS as fundamental, there are a number
of other capabilities that are almost universally found in commercial DBMS's. These are:
Support for at least one data model, or mathematical abstraction through which the user can
view the data.

Support for certain high-level languages that allow the user to define the structure of data,
access data, and manipulate data.
Transaction management, the capability to provide correct, concurrent access to the database
by many users at once.
Access control, the ability to limit access to data by unauthorized users, and the ability to
check the validity of data.
Resiliency, the ability to recover from system failures without losing data.
Data Models Each DBMS provides at least one abstract model of data that allows the user
to see information not as raw bits, but in more understandable terms. In fact, it is usually possible
to see data at several levels of abstraction. At a relatively low level, a DBMS commonly allows
us to visualize data as composed of files.
Efficient File Access The ability to store a file is not remarkable: the file system associated
with any operating system does that. The capability of a DBMS is seen when we access the data of
a file. For example, suppose we wish to find the manager of employee "Clark Kent". If the
company has thousands of employees, It is very expensive to search the entire file to find the one
with NAME="Clark Kent". A DBMS helps us to set up "index files," or "indices," that allow us to
access the record for "Clark Kent" in essentially one stroke no matter how large the file is. Likewise,
insertion of new records or deletion of old ones can be accomplished in time that is small and
essentially constant, independent of the file’s length. Another thing a DBMS helps us do is navigate
among files, that is, to combine values in two or more files to obtain the information we want.
Query Languages To make access to files easier, a DBMS provides a query language, or
data manipulation language, to express operations on files. Query languages differ in the level of
detail they require of the user, with systems based on the relational data model generally
requiring less detail than languages based on other models.

Transaction Management

Another important capability of a DBMS is the ability to
manage simultaneously large numbers of transactions, which are procedures operating on the
database. Some databases are so large that they can only be useful if they are operated upon
simultaneously by many computers: often these computers are dispersed around the country or
the world. The database systems used by banks, accessed almost instantaneously by hundreds or
thousands of automated teller machines (ATM), as well as by an equal or greater number of
employees in the bank branches, is typical of this sort of database. An airline reservation system
is another good example.
Sometimes, two accesses do not interfere with each other. For example, any number of
transactions can be reading your bank balance at the same time, without any inconsistency. [3]But
if you are in the bank depositing your salary check at the exact instant your spouse is extracting
money from an automatic teller, the result of the two transactions occurring simultaneously and
without coordination is unpredictable. Thus, transactions that modify a data item must “lock out”
other transactions trying to read or write that item at the same time. A DBMS must therefore
provide some form of concurrency control to prevent uncoordinated access to the same data item

by more than one transaction.
Even more complex problems occur when the database is distributed over many different
computer systems, perhaps with duplication of data to allow both faster local access and to
protect against the destruction of data if one computer crashes.
Security of Data A DBMS must not only protect against loss of data when crashes occur,
as we just mentioned, but it must prevent unauthorized access. For example, only users with a
certain clearance should have access to the salary field of an employee file, and the DBMS must
be able associate with the various users their privileges to see files, fields within files, or other
subsets of the data in the database. Thus a DBMS must maintain a table telling for each user
known to it, what access privileges the user has for each object. For example, one user may be
allowed to read a file, but not to insert or delete data; another may not be allowed to see the file at
all, while a third may be allowed to read or modify the file at will.

DBMS Types
Designers developed three different types of database structures: hierarchical, network, and
relational. Hierarchical and network were first developed but relational has become dominant.
While the relational design is dominant, the older databases have not been dropped. Companies
that installed a hierarchical system such as IMS in the 1970s will be using and maintaining these
databases for years to come even though new development is being done on relational systems.
These older systems are often referred to as legacy systems.

1, teller  ['telə]
n. (美)出纳员;讲述者;讲故事者;计票员

2, reservation  [,rezə'veiʃən]
n. 预约,预订;保留
3, at will 

Continue reading it-e-32 Introduction to DBMS


  • 一个业务用例描述的是业务过程——而不是软件系统过程。
  • 一个业务用例为涉众创造价值。这些涉众要么是业务参与者要么是业务工作者。
  • 一个业务用例可以超越组织的边界。有些构架师对于这一点有非常严密的态度。许多业务用例确实超越来组织的边界,但是有些业务用例仅仅关注于一个组织。


  • 1.业务用例就是要完成的业务,系统用例是系统要做的事情,两者的域不同。
  • 2.业务建模主要描述了该项目涉及的所有业务,需求模型主要是描述为了满足业务需求系统要做什么,因此,需求模型与业务模型相比,它描述的只是业务模型的一个子集。
  • 3.比方说我们设计一个自动提款机系统,它可以满足用户的取款、改密、查询等需求,那么这些需求就是业务用例;但是用户又分为借记卡用户和信用卡用户,那么根据业务规则,不同的卡用户的取款、改密、查询的过程是不一样的,所以系统为了满足这种业务需求会包含到两个子用例里实现,这种子用例就是系统用例。也就是说系统用例就是系统为了满足这种业务需求要做什么。






Continue reading 业务用例与系统用例的区别

it-e-31 Steganography and Honeytokens

Steganography is a method of embedding electronic messages into a media file (for example, an image or audio file) by altering nonessential lines of code; the changes are imperceptible. The message remains undetected until unencrypted. Honeytokens is any kind of tantalizing false data, including phony patient records at a hospital, lists of invalid social security numbersor even simply a word processing file named "HR-salaries," that's stored in a restricted part of the network. If anyone tries to access the files the security team is alerted to the trespassing before the intruder can do any real damage.

1, imperceptible  [,impə'septəbl]
a. 不能感知的,不知不觉的,微细的

2, steganography  [,stegə'nɔgrəfi]
n. 速记式加密
3, tantalizing  ['tæntəlaiziŋ]
a. 诱人的
4, phony  ['fəuni]
a. 假的,伪造的
5, trespassing 
n. 擅自进入
v. 侵入;犯罪(trespass的ing形式)
6, intruder  [in'tru:də]
n. 侵入者,干扰者,妨碍者

Continue reading it-e-31 Steganography and Honeytokens




ServiceMix有三种部署方式:单独程序方式,servlet方式,Geronimo and JBoss.整合方式。这里主要介绍servlet方式,因为这样可以整合到任何servlet容器中。






<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE web-app

    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"




  <display-name>ServiceMix Web Application</display-name>

  <description>Deploys ServiceMix inside a Web Application</description>




    <param-value>/WEB-INF/jmx.xml /WEB-INF/core.xml /WEB-INF/activemq.xml</param-value>











Spring 监听器

  <!-- servlet mappings -->


  <!-- the main JMX servlet -->







  <!--  the HTTP binding servlet -->


  <!-- START SNIPPET: servicemix-http-->








http bean组件(BC)servlet






  <!-- END SNIPPET: httpBinding -->










<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns:sm=""





  <!-- the JBI container -->

  <sm:container id="jbi"













      <!--  an example HTTP binding for use by the SpringBindingServlet  -->

      <!-- START SNIPPET: http -->

      <sm:activationSpec componentName="servicemix-http" service="foo:httpBinding" destinationService="foo:echo">



            <http:configuration managed="true" />


              <http:endpoint service="foo:httpBinding"





配置url, 会被tomcat自动转换为serverapp/jbi/ exampleUri




" />





使用http BC,作为一个消费者(consumer)目标指向服务引擎(SE)foo:echo

      <!-- END SNIPPET: http -->


      <!--  a simple Echo service to test InOut message exchanges using HTTP-->

      <sm:activationSpec componentName="echo" service="foo:echo" >


          <bean class="org.apache.servicemix.components.HelloWorldComponent">

            <property name="property" value="name"/>




SE foo:echo,这是一个简单的helloworld



经过这样的配置和在web.xml中配置的servlet,那么uri pattern形如 /jbi/exampleUri请求foo:httpBinding (BC),在ESB内部foo:httpBinding通过消息路由(normalized message router)foo:echo通信




测试页面使用ajax请求/jbi/exampleUri经过foo:httpBinding, foo:echo处理返回信息。



Continue reading ServiceMix环境配置



使用专门的存储区域网成本很高,而利用普通的数据网来传输SCSI数据实现和SAN相似的功能可以大大的降低成本,同时提高系统的灵活性。iSCSI就是这样一种技术,它利用普通的TCP/IP网来传输本来用存储区域网来传输的SCSI数据块。iSCSI的成本相对SAN来说要低不少。随着千兆网的普及,万兆网也逐渐的进入主流,使iSCSI的速度相对SAN来说并没有太大的劣势。iSCSI目前存在的主要问题是:(1)新兴的技术,提供完整解决方案的厂商较少,对管理者技术要求高;(2)通过普通网卡存取iSCSI数据时,解码成SCSI需要CPU进行运算,增加了系统性能开销,如果采用专门的 iSCSI网卡虽然可以减少系统性能开销,但会大大增加成本;(3)使用数据


Continue reading 【转】几种常见的网络存储技术的比较研究



我们有时候希望回车键敲在文本框(input element)里来提交表单(form),但有时候又不希望如此。比如搜索行为,希望输入完关键词之后直接按回车键立即提交表单,而有些复杂表单,可能要避免回车键误操作在未完成表单填写的时候就触发了表单提交。
4、其他表单元素如textarea、select不影响,radio checkbox不影响触发规则,但本身在FF下会响应回车键,在IE下不响应。
实际应用的时候,要让表单响应回车键很容易,保证表单里有个type=”submit”的按钮就行。而当只有一个文本框又不希望响应回车键怎么办呢?我的方法有点别扭,就是再写一个无意义的文本框,隐藏起来 但是如果设置了submit tabindex=0,则会提交  。根据第3条规则,我们在用button的时候,尽量显式声明type以使浏览器表现一致。

Continue reading 【转】回车键触发表单提交的问题


C/S 结构是建立在中间件产品基础之上的,要求应用开发者自己去处理事务管理、消息队列、数据的复制和同步、通信安全等系统级的问题。这对应用开发者提出了较高的要求,而且迫使应用开发者投入很多精力来解决应用程序以外的问题。这使得应用程序的维护、移植和互操作变得复杂。如果客户端是在不同的操作系统上,C/S结构的软件需要开发不同版本的客户端软件。但是,与B/S结构相比,C/S技术发展历史更为“悠久”。从技术成熟度及软件设计、开发人员的掌握水平来看,C/S技术应是更成熟、更可靠的。 
4、C/S 模式的优点和缺点 
★ C/S 模式的优点 
● 由于客户端实现与服务器的直接相连,没有中间环节,因此响应速度快。 
● C/S结构的管理信息系统具有较强的事务处理能力,能实现复杂的业务流程。
★ C/S 模式的缺点 
● 需要专门的客户端安装程序,分布功能弱,针对点多面广且不具备网络条件的用户群体,不能够实现快速部署安装和配置。 
★ B/S 模式的优点 
● 业务扩展简单方便,通过增加网页即可增加服务器功能。 
● 维护简单方便,只需要改变网页,即可实现所有用户的同步更新。 
● 开发简单,共享性强。 
★ B/S 模式的缺点 
● 个性化特点明显降低,无法实现具有个性化的功能要求。 
● 操作是以鼠标为最基本的操作方式,无法满足快速操作的要求。 
● 页面动态刷新,响应速度明显降低。 
● 无法实现本地分页缓存显示,给数据库访问造成较大的压力。 


Continue reading C/S与B/S架构


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