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河北工程大学毕业论文(设计)论文题目:鸿海种业仓库管理系统的论文题目:鸿海种业仓库管理系统的设计与实现作者姓名:石成华专业班级:信管1001学号信息:指导老师:张贵炜论文日期:2023.04.10

数据仓库

数据仓库为商务运作提供结构与工具,以便系统地组织、理解和使用数据进行决策。大量组织机构已经发现,在当今这个充满竞争、快速发展的世界,数据仓库是一个有价值的工具。在过去的几年中,许多公司已花费数百万美元,建立公司范围的数据仓库。许多人感到,随着工业竞争的加剧,数据仓库成了必备的最新营销武器——通过更多地了解客户需求而保住客户的途径。

“那么”,你也许会充满神秘地问,“到底什么是数据仓库?”

数据仓库已被多种方式定义,使得很难严格地定义它。宽松地讲,数据仓库是一个数据库,它与组织机构的操作数据库分别维护。数据仓库系统允许将各种应用系统集成在一起,为统一的历史数据分析提供坚实的平台,对信息解决提供支持。

按照W.

H.

Inmon,一位数据仓库系统构造方面的领头建筑师的说法,“数据仓库是一个面向主题的、集成的、时变的、非易失的数据集合,支持管理决策制定”。这个简短、全面的定义指出了数据仓库的重要特性。四个关键词,面向主题的、集成的、时变的、非易失的,将数据仓库与其它数据存储系统(如,关系数据库系统、事务解决系统、和文献系统)相区别。让我们进一步看看这些关键特性。

(1)面向主题的:数据仓库围绕一些主题,如顾客、供应商、产品和销售组织。数据仓库关注决策者的数据建模与分析,而不是构造组织机构的平常操作和事务解决。因此,数据仓库排除对于决策无用的数据,提供特定主题的简明视图。

(2)集成的:通常,构造数据仓库是将多个异种数据源,如关系数据库、一般文献和联机事务解决记录,集成在一起。使用数据清理和数据集成技术,保证命名约定、编码结构、属性度量的一致性等。

(3)时变的:数据存储从历史的角度(例如,过去5-10

年)提供信息。数据仓库中的关键结构,隐式或显式地包含时间元素。

(4)

非易失的:数据仓库总是物理地分离存放数据;这些数据源于操作环境下的应用数据。由于这种分离,数据仓库不需要事务解决、恢复和并行控制机制。通常,它只需要两种数据访问:数据的初始化装入和数据访问。概言之,数据仓库是一种语义上一致的数据存储,它充当决策支持数据模型的物理实现,并存放公司决策所需信息。数据仓库也经常被看作一种体系结构,通过将异种数据源中的数据集成在一起而构造,支持结构化和启发式查询、分析报告和决策制定。

“好”,你现在问,“那么,什么是建立数据仓库?”根据上面的讨论,我们把建立数据仓库看作构造和使用数据仓库的过程。数据仓库的构造需要数据集成、数据清理、和数据统一。运用数据仓库经常需要一些决策支持技术。这使得“知识工人”(例如,经理、分析人员和主管)可以使用数据仓库,快捷、方便地得到数据的总体视图,根据数据仓库中的信息做出准确的决策。有些作者使用术语“建立数据仓库”表达构造数据仓库的过程,而用术语“仓库DBMS”表达管理和使用数据仓库。我们将不区分两者。

“组织机构如何使用数据仓库中的信息?”许多组织机构正在使用这些信息支持商务决策活动,涉及:

(1)、增长顾客关注,涉及分析顾客购买模式(如,爱慕买什么、购买时间、预算周期、消费习惯);

(2)、根据季度、年、地区的营销情况比较,重新配置产品和管理投资,调整生产策略;

(3)、分析运作和查找利润源;

(4)、管理顾客关系、进行环境调整、管理合股人的资产开销。从异种数据库集成的角度看,数据仓库也是十分有用的。许多组织收集了形形色色数据,并由多个异种的、自治的、分布的数据源维护大型数据库。集成这些数据,并提供简便、有效的访问是非常希望的,并且也是一种挑战。数据库工业界和研究界都正朝着实现这一目的竭尽全力。对于异种数据库的集成,传统的数据库做法是:在多个异种数据库上,建立一个包装程序和一个集成程序(或仲裁程序)。这方面的例子涉及IBM的数据连接程序和Informix的数据刀。当一个查询提交客户站点,一方面使用元数据字典对查询进行转换,将它转换成相应异种站点上的查询。然后,将这些查询映射和发送到局部查询解决器。由不同站点返回的结果被集成为全局回答。这种查询驱动的方法需要复杂的信息过滤和集成解决,并且与局部数据源上的解决竞争资源。这种方法是低效的,并且对于频繁的查询,特别是需要聚集操作的查询,开销很大。对于异种数据库集成的传统方法,数据仓库提供了一个有趣的替代方案。数据仓库使用更新驱动的方法,而不是查询驱动的方法。这种方法将来自多个异种源的信息预先集成,并存储在数据仓库中,供直接查询和分析。与联机事务解决数据库不同,数据仓库不包含最近的信息。然而,数据仓库为集成的异种数据库系统带来了高性能,由于数据被拷贝、预解决、集成、注释、汇总,并重新组织到一个语义一致的数据存储中。在数据仓库中进行的查询解决并不影响在局部源上进行的解决。此外,数据仓库存储并集成历史信息,支持复杂的多维查询。这样,建立数据仓库在工业界已非常流行。1.操作数据库系统与数据仓库的区别由于大多数人都熟悉商品关系数据库系统,将数据仓库与之比较,就容易理解什么是数据仓库。联机操作数据库系统的重要任务是执行联机事务和查询解决。这种系统称为联机事务解决(OLTP)系统。它们涵盖了一个组织的大部分平常操作,如购买、库存、制造、银行、工资、注册、记帐等。另一方面,数据仓库系统在数据分析和决策方面为用户或“知识工人”提供服务。这种系统可以用不同的格式组织和提供数据,以便满足不同用户的形形色色需求。这种系统称为联机分析解决(OLAP)系统。OLTP和OLAP的重要区别概述如下。(1)用户和系统的面向性:OLTP是面向顾客的,用于办事员、客户、和信息技术专业人员的事务和查询解决。OLAP是面向市场的,用于知识工人(涉及经理、主管、和分析人员)的数据分析。(2)数据内容:OLTP系统管理当前数据。通常,这种数据太琐碎,难以方便地用于决策。OLAP系统管理大量历史数据,提供汇总和聚集机制,并在不同的粒度级别上存储和管理信息。这些特点使得数据容易用于见多识广的决策。(3)数据库设计:通常,OLTP系统采用实体-联系(ER)模型和面向应用的数据库设计。而OLAP系统通常采用星形或雪花模型和面向主题的数据库设计。(4)视图:OLTP系统重要关注一个公司或部门内部的当前数据,而不涉及历史数据或不同组织的数据。相比之下,由于组织的变化,OLAP系统经常跨越数据库模式的多个版本。OLAP系统也解决来自不同组织的信息,由多个数据存储集成的信息。由于数据量巨大,OLAP数据也存放在多个存储介质上。(5)、访问模式:OLTP系统的访问重要由短的、原子事务组成。这种系统需要并行控制和恢复机制。然而,对OLAP系统的访问大部分是只读操作(由于大部分数据仓库存放历史数据,而不是当前数据),尽管许多也许是复杂的查询。OLTP和OLAP的其它区别涉及数据库大小、操作的频繁限度、性能度量等。2.但是,为什么需要一个分离的数据仓库

“既然操作数据库存放了大量数据”,你注意到,“为什么不直接在这种数据库上进行联机分析解决,而是此外花费时间和资源去构造一个分离的数据仓库?”分离的重要因素是提高两个系统的性能。操作数据库是为已知的任务和负载设计的,如使用主关键字索引和散列,检索特定的记录,和优化“罐装的”查询。另一方面,数据仓库的查询通常是复杂的,涉及大量数据在汇总级的计算,也许需要特殊的数据组织、存取方法和基于多维视图的实现方法。在操作数据库上解决OLAP

查询,也许会大大减少操作任务的性能。

此外,操作数据库支持多事务的并行解决,需要加锁和日记等并行控制和恢复机制,以保证一致性和事务的强健性。通常,OLAP

查询只需要对数据记录进行只读访问,以进行汇总和聚集。假如将并行控制和恢复机制用于这OLAP

操作,就会危害并行事务的运营,从而大大减少OLTP

系统的吞吐量。

最后,数据仓库与操作数据库分离是由于这两种系统中数据的结构、内容和用法都不相同。决策支持需要历史数据,而操作数据库一般不维护历史数据。在这种情况下,操作数据库中的数据尽管很丰富,但对于决策,经常还是远远不够的。决策支持需要将来自异种源的数据统一(如,聚集和汇总),产生高质量的、纯净的和集成的数据。相比之下,操作数据库只维护具体的原始数据(如事务),这些数据在进行分析之前需要统一。由于两个系统提供很不相同的功能,需要不同类型的数据,因此需要维护分离的数据库。

Data

warehousing

provides

architectures

and

tools

for

business

executives

to

systematically

organize,

understand,

and

use

their

data

to

make

strategic

decisions.

A

large

number

of

organizations

have

found

that

data

warehouse

systems

are

valuable

tools

in

today's

competitive,

fast

evolving

world.

In

the

last

several

years,

many

firms

have

spent

millions

of

dollars

in

building

enterprise-wide

data

warehouses.

Many

people

feel

that

with

competition

mounting

in

every

industry,

data

warehousing

is

the

latest

must-have

marketing

weapon

——

way

to

keep

customers

by

learning

more

about

their

needs.

“So",

you

may

ask,

full

of

intrigue,

“what

exactly

is

a

data

warehouse?"

Data

warehouses

have

been

defined

in

many

ways,

making

it

difficult

to

formulate

rigorous

definition.

Loosely

speaking,

a

data

warehouse

refers

to

database

that

is

maintained

separately

from

an

organization's

operational

databases.

Data

warehouse

systems

allow

for

the

integration

of

a

variety

of

application

systems.

They

support

information

processing

by

providing

solid

platform

of

consolidated,

historical

data

for

analysis.

According

to

W.

H.

Inmon,

a

leading

architect

in

the

construction

of

data

warehouse

systems,

“a

data

warehouse

is

a

subject-oriented,

integrated,

time-variant,

and

nonvolatile

collection

of

data

in

support

of

management's

decision

making

process."

This

short,

but

comprehensive

definition

presents

the

major

features

of

a

data

warehouse.

The

four

keywords,

subject-oriented,

integrated,

time-variant,

and

nonvolatile,

distinguish

data

warehouses

from

other

data

repository

systems,

such

as

relational

database

systems,

transaction

processing

systems,

and

file

systems.

Let's

take

a

closer

look

at

each

of

these

key

features.

(1).Subject-oriented:

A

data

warehouse

is

organized

around

major

subjects,

such

as

customer,

vendor,

product,

and

sales.

Rather

than

concentrating

on

the

day-to-day

operations

and

transaction

processing

of

an

organization,

data

warehouse

focuses

on

the

modeling

and

analysis

of

data

for

decision

makers.

Hence,

data

warehouses

typically

provide

a

simple

and

concise

view

around

particular

subject

issues

by

excluding

data

that

are

not

useful

in

the

decision

support

process.

(2)

Integrated:

A

data

warehouse

is

usually

constructed

by

integrating

multiple

heterogeneous

sources,

such

as

relational

databases,

flat

files,

and

on-line

transaction

records.

Data

cleaning

and

data

integration

techniques

are

applied

to

ensure

consistency

in

naming

conventions,

encoding

structures,

attribute

measures,

and

so

on.

(3).Time-variant:

Data

are

stored

to

provide

information

from

a

historical

perspective

(e.g.,

the

past

5-10

years).

Every

key

structure

in

the

data

warehouse

contains,

either

implicitly

or

explicitly,

an

element

of

time.

(4)Nonvolatile:

A

data

warehouse

is

always

physically

separate

store

of

data

transformed

from

the

application

data

found

in

the

operational

environment.

Due

to

this

separation,

a

data

warehouse

does

not

require

transaction

processing,

recovery,

and

concurrency

control

mechanisms.

It

usually

requires

only

two

operations

in

data

accessing:

initial

loading

of

data

and

access

of

data.

In

sum,

data

warehouse

is

a

semantically

consistent

data

store

that

serves

as

a

physical

implementation

of

a

decision

support

data

model

and

stores

the

information

on

which

an

enterprise

needs

to

make

strategic

decisions.

A

data

warehouse

is

also

often

viewed

as

an

architecture,

constructed

by

integrating

data

from

multiple

heterogeneous

sources

to

support

structured

and/or

ad

hoc

queries,

analytical

reporting,

and

decision

making.

“OK",

you

now

ask,

“what,

then,

is

data

warehousing?"

Based

on

the

above,

we

view

data

warehousing

as

the

process

of

constructing

and

using

data

warehouses.

The

construction

of

a

data

warehouse

requires

data

integration,

data

cleaning,

and

data

consolidation.

The

utilization

of

a

data

warehouse

often

necessitates

a

collection

of

decision

support

technologies.

This

allows

“knowledge

workers"

(e.g.,

managers,

analysts,

and

executives)

to

use

the

warehouse

to

quickly

and

conveniently

obtain

an

overview

of

the

data,

and

to

make

sound

decisions

based

on

information

in

the

warehouse.

Some

authors

use

the

term

“data

warehousing"

to

refer

only

to

the

process

of

data

warehouse

construction,

while

the

term

warehouse

DBMS

is

used

to

refer

to

the

management

and

utilization

of

data

warehouses.

We

will

not

make

this

distinction

here.

“How

are

organizations

using

the

information

from

data

warehouses?"

Many

organizations

are

using

this

information

to

support

business

decision

making

activities,

including:

(1)

increasing

customer

focus,

which

includes

the

analysis

of

customer

buying

patterns

(such

as

buying

preference,

buying

time,

budget

cycles,

and

appetites

for

spending),

(2)

repositioning

products

and

managing

product

portfolios

by

comparing

the

performance

of

sales

by

quarter,

by

year,

and

by

geographic

regions,

in

order

to

fine-tune

production

strategies,

(3)

analyzing

operations

and

looking

for

sources

of

profit,

(4)

managing

the

customer

relationships,

making

environmental

corrections,

and

managing

the

cost

of

corporate

assets.

Data

warehousing

is

also

very

useful

from

the

point

of

view

of

heterogeneous

database

integration.

Many

organizations

typically

collect

diverse

kinds

of

data

and

maintain

large

databases

from

multiple,

heterogeneous,

autonomous,

and

distributed

information

sources.

To

integrate

such

data,

and

provide

easy

and

efficient

access

to

it

is

highly

desirable,

yet

challenging.

Much

effort

has

been

spent

in

the

database

industry

and

research

community

towards

achieving

this

goal.

The

traditional

database

approach

to

heterogeneous

database

integration

is

to

build

wrappers

and

integrators

(or

mediators)

on

top

of

multiple,

heterogeneous

databases.

A

variety

of

data

joiner

and

data

blade

products

belong

to

this

category.

When

a

query

is

posed

to

a

client

site,

a

metadata

dictionary

is

used

to

translate

the

query

into

queries

appropriate

for

the

individual

heterogeneous

sites

involved.

These

queries

are

then

mapped

and

sent

to

local

query

processors.

The

results

returned

from

the

different

sites

are

integrated

into

a

global

answer

set.

This

query-driven

approach

requires

complex

information

filtering

and

integration

processes,

and

competes

for

resources

with

processing

at

local

sources.

It

is

inefficient

and

potentially

expensive

for

frequent

queries,

especially

for

queries

requiring

aggregations.

Data

warehousing

provides

an

interesting

alternative

to

the

traditional

approach

of

heterogeneous

database

integration

described

above.

Rather

than

using

a

query-driven

approach,

data

warehousing

employs

an

update-driven

approach

in

which

information

from

multiple,

heterogeneous

sources

is

integrated

in

advance

and

stored

in

a

warehouse

for

direct

querying

and

analysis.

Unlike

on-line

transaction

processing

databases,

data

warehouses

do

not

contain

the

most

current

information.

However,

data

warehouse

brings

high

performance

to

the

integrated

heterogeneous

database

system

since

data

are

copied,

preprocessed,

integrated,

annotated,

summarized,

and

restructured

into

one

semantic

data

store.

Furthermore,

query

processing

in

data

warehouses

does

not

interfere

with

the

processing

at

local

sources.

Moreover,

data

warehouses

can

store

and

integrate

historical

information

and

support

complex

multidimensional

queries.

As

result,

data

warehousing

has

become

very

popular

in

industry.

1.

Differences

between

operational

database

systems

and

data

warehouses

Since

most

people

are

familiar

with

commercial

relational

database

systems,

it

is

easy

to

understand

what

a

data

warehouse

is

by

comparing

these

two

kinds

of

systems.

The

major

task

of

on-line

operational

database

systems

is

to

perform

on-line

transaction

and

query

processing.

These

systems

are

called

on-line

transaction

processing

(OLTP)

systems.

They

cover

most

of

the

day-to-day

operations

of

an

organization,

such

as,

purchasing,

inventory,

manufacturing,

banking,

payroll,

registration,

and

accounting.

Data

warehouse

systems,

on

the

other

hand,

serve

users

or

“knowledge

workers"

in

the

role

of

data

analysis

and

decision

making.

Such

systems

can

organize

and

present

data

in

various

formats

in

order

to

accommodate

the

diverse

needs

of

the

different

users.

These

systems

are

known

as

on-line

analytical

processing

(OLAP)

systems.

The

major

distinguishing

features

between

OLTP

and

OLAP

are

summarized

as

follows.

(1).

Users

and

system

orientation:

An

OLTP

system

is

customer-oriented

and

is

used

for

transaction

and

query

processing

by

clerks,

clients,

and

information

technology

professionals.

An

OLAP

system

is

market-oriented

and

is

used

for

data

analysis

by

knowledge

workers,

including

managers,

executives,

and

analysts.

(2).

Data

contents:

An

OLTP

system

manages

current

data

that,

typically,

are

too

detailed

to

be

easily

used

for

decision

making.

An

OLAP

system

manages

large

amounts

of

historical

data,

provides

facilities

for

summarization

and

aggregation,

and

stores

and

manages

information

at

different

levels

of

granularity.

These

features

make

the

data

easier

for

use

in

informed

decision

making.

(3).

Database

design:

An

OLTP

system

usually

adopts

an

entity-relationship

(ER)

data

model

and

an

application

-oriented

database

design.

An

OLAP

system

typically

adopts

either

star

or

snowflake

model,

and

a

subject-oriented

database

design.

(4).

View:

An

OLTP

system

focuses

mainly

on

the

current

data

within

an

enterprise

or

department,

without

referring

to

historical

data

or

data

in

different

organizations.

In

contrast,

an

OLAP

system

often

spans

multiple

versions

of

database

schema,

due

to

the

evolutionary

process

of

an

organization.

OLAP

systems

also

deal

with

information

that

originates

from

different

organizations,

integrating

information

from

many

data

stores.

Because

of

their

huge

volume,

OLAP

data

are

stored

on

multiple

storage

media.

(5).

Access

patterns:

The

access

patterns

of

an

OLTP

system

consist

mainly

of

short,

atomic

transactions.

Such

a

system

requires

concurrency

control

and

recovery

mechanisms.

However,

accesses

to

OLAP

systems

are

mostly

read-only

operations

(since

most

data

warehouses

store

historical

rather

than

up-to-date

information),

although

many

could

be

complex

queries.

Other

features

which

distinguish

between

OLTP

and

OLAP

systems

include

database

size,

frequency

of

operations,

and

performance

metrics

and

so

on.

2.

But,

why

have

separate

data

warehouse?

“Since

operational

databases

store

huge

amounts

of

data",

you

observe,

“why

not

perform

on-line

analytical

processing

directly

on

such

databases

instead

of

spending

additional

time

and

resources

to

construct

a

separate

data

warehouse?"

A

major

reason

for

such

separation

is

to

help

promote

the

high

performance

of

both

systems.

An

operational

database

is

designed

and

tuned

from

known

tasks

and

workloads,

such

as

indexing

and

hashing

using

primary

keys,

searching

for

particular

records,

and

optimizing

“canned"

queries.

On

the

other

hand,

data

warehouse

queries

are

often

complex.

They

involve

the

computation

of

large

groups

of

data

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