中国矿业大学大学企业工资福利社会保障系统论文(论文)大学 大学毕业设计

(

论文

)

外文翻译

学生姓名

罗旭

专业班级

计算机

08-2

班

指导教师

王影

魏琦

职

称

高工

讲师

所在单位

信息科学系计算机教研室

教研室主任

宋丽芳

完成日期

2012

年

4

月

13

日

MySQL

5

MySQL's original developer intent is to use the mSQL and their rapid low- level routines

( ISAM ) to connect to form. After some tests, the developers concluded: mSQL and there is

no need for them so fast and flexible. This led to a use almost like mSQL API interface for

their database of the new SQL interface, so, the API is designed to allow for use on the mSQL

to write the third party code easier to transfer to MySQL.

The name MySQL is how come is not clear. Basic guide and a large number of libraries

and tools with the prefix

co-founder of

MySQL AB Monty Widenius The daughter also named My. The two which one it was given

the name MySQL remains a mystery, including developers, also do not know.

MySQL Dolphins Logo name is

from the users in the

name

is

made

from

Africa

and

Swaziland's

open

source

software

developer

Ambrose

Twebaze.

According

to

Ambrose,

Sakila

from

a

SiSwati

Swaziland

dialect,

but

also

in

the

Ambrose 's home town of Uganda, near Tanzania's Arusha is one of the town's name.

And other large databases such as Oracle, DB2, SQL Server compared to MySQL, has

its own disadvantages, such as small size, limited functionality ( MySQL Cluster function and

efficiency are relatively poor ), but it did not reduce its popularity. For the average individual

users and small and medium enterprises, the functionality provided by MySQL is more than

sufficient, and because MySQL is open source software, thus can greatly reduce the total cost

of ownership.

LAMP:

The current Internet popular website architecture is LAMP ( Linux + Apache + MySQL

+ PHP / Perl / Python ) and LNMP ( Linux + Nginx + MySQL + php / Perl / Python ), which

uses the Linux as the operating system, Apache and Nginx as the Web server, MySQL as the

database,

PHP

/

Perl

/

Python

as

a

server- side

script

interpreter.

As

a

result

of

the

four

software are free or open source software ( FLOSS ), so use this way without spending a dime

( except artificial cost ) to establish a stable, free website system.

MyISAMMysql

default

database,

the

most

commonly

used.

Have

a

high

insertion,

search

speed,

but

does

not

support

transactions

InnoDB

transactional

database

preferred

engine,

support

for

ACID

affairs,

support

row-level

locking

BDB

from

Berkeley

DB,

transactional database for another option, support for COMMIT and ROLLBACK and other

transaction characteristics of Memory all of the data in memory storage engine, with a high

insertion, update and query efficiency. But it will take and data is proportional to the amount

of

memory

space.

And

its

content

in

the

Mysql

restart

lost

when

Merge

will

be

a

certain

amount of MyISAM

combined into a whole, in the large scale data storage is useful

when

6

Archive is very suitable for storing a large number of independent, as history data. Because

they

don't

often

been

read.

Archive

has

efficient

insertion

speed,

but

its

effect

on

query

support

relatively

poor

Federated

different

Mysql

server

logic

together,

form

a

complete

database. Very suitable for distributed application of Cluster / NDB high redundancy storage

engine,

using

multiple

data

machine

combined

to

provide

services

to

improve

overall

performance

and

safety.

Suitable

for

large

amount

of

data,

safety

and

performance

requirements of high CSV application logic

comma separated data storage engine Cluster /

NDB.

BlackHole black engine, written in any data will disappear, generally used for recording

binlog replication of the relay EXAMPLE storage engine is a don't do anything stub engine. It

is

designed

as

MySQL

one

example

in

the

source

code,

used

to

demonstrate

how

to

start

writing

a

new

storage

engine.

Similarly,

it

is

of

major

interest

to

developers.

EXAMPLE

storage

engine

does

not

support

indexing.

In

addition,

Mysql

storage

engine

interface

definition

of

good.

Interested

developers

can

by

reading

the

document

prepared

its

own

storage engine.

The index is a special file ( InnoDB data index is a table space is an integral part of ),

they

contain

the

data

inside

and

outside

all

recorded

reference

pointer.

The

index

is

not

a

panacea, the index can speed up data retrieval operation, but can make the data modification

operation slow. Each modified data recording, index must refresh time. In order to in certain

procedures to remedy this one flaw, many SQL command has a DELAY_KEY_WRITE. This

option is the role of temporary suppression of MySQL in the order of each insert a new record

and each modified an existing immediately after the index on the index to refresh, refresh will

wait until all record insert / modified after. The need to bring many new record is inserted into

a data table of the occasion, the DELAY_KEY_WRITE option effects will be very obvious.

In addition, the index will be in hard disk takes up considerable space. Therefore should only

for the most frequent

queries

and most often sorted data column is

indexed. Note that, if a

data column contains many duplicate content, as it establishes index is not much actual effect.

From

theoretic

tell,

can

provide

data

and

each

of

the

fields

were

built

an

index,

but

MySQL the same data and index number is limited to 16.

data table index

With InnoDB data table, in the InnoDB table, index on the InnoDB table importance is

much

greater.

In

InnoDB

data

table,

the

index

will

not

only

play

a

role

in

the

search

data

records,

or

data

row

level

locking

mechanism,

acenaphthene

based.

The

data

row

level

locking

an individual record, do not allow other users to access. The lock will be affected ( but not

7

limited

to

)

SELECT,

LOCKINSHAREMODE,

SELECT,

INSERT,

UPDATE

and

FORUPDATE commands and DELETE command. For efficiency reasons, InnoDB data row

level locking actually occur in their index, rather than the data itself. Obviously, the data row

level locking mechanism only in relation to the data table having a suitable index for locking

time to work.

2 limit

If the WHERE clause in the query terms are not equal ( WHERE coloum!= )MySQL ,

will not be able to use the index. Similarly, if the WHERE clause in the query terms used in

function ( WHEREDAY ( column ) = MySQL ), will be unable to use the index. In the JOIN

operation ( from multiple data extraction data ), MySQL only in the primary and foreign keys

to the same data type to use index.

If

the

WHERE

clause

in

the

query

conditions

using

comparison

operators

LIKE

and

REGEXP, MySQL only in search of template first character is not a wildcard conditions can

use the index. For example, if the query is ' LIKE 'abc%, MySQL will use the index; if the

query is ' LIKE %abc, ' MySQL will not use index.

In

the

operation

of

ORDERBY,

MySQL

only

in

the

sorting

condition

is

not

a

query

condition expression condition that use index. ( even so, in a plurality of data query, even if

the index is available, the index in accelerating ORDERBY has no effect). If a data column

contains many duplicate values, even if it establishes index will not have a good effect. For

example, if a data column contains the net is something such as

there is no need for it to create an index.

Only when the database has enough test data, its performance test results have practical

reference

value.

If

the

test

database

only

hundreds

of

data

recording,

they

are

often

in

executing

the

first

query

command

after

being

loaded

into

memory,

it

will

make

the

subsequent

inquiry

command

to

perform

very

fast

--

with

or

without

using

an

index.

Only

when the records in a database of more than 1000, the amount of data is more than the amount

of memory on the MySQL server, database performance testing results are meaningful. On

the uncertainty in which data should create index on a column of the time, people from the

EXPLAINSELECT command there can often get some help. This is simply to give a common

SELECT command plus a EXPLAIN keyword as a prefix. With this key, MySQL will not to

follow

the

SELECT

command,

but

to

analyze

it.

MySQL

will

be

in

the

form

of

the

query

execution

process

and

uses

the

index

information

list.

In

the

output

of

the

EXPLAIN

command results, the first column is the data read from the database table name, they are to

be read in

the order.

The type

column specifies

the data table

and other

table relationships

( JOIN ). In various types of relationships, efficiency is highest in system, followed by const,

8

eq_ref, ref, range, index and All ( All means: a data table corresponding to each record, this

table

all

records

must

be

read

again

--

this

can

often

be

used

to

an

index

to

avoid

).

Possible_keys data column gives the MySQL in search of the data record can be chosen each

index. Key data column is MySQL practical selection index, this index in bytes of the key_len

length

in

the

columns

of

the

data

given

in

the.

For

example,

for

a

INTEGER

data

column

index, the byte length will be 4. If used in the composite index, the key_len data column can

also see MySQL specific use of it which part. As a general rule, key_len data column value in

the smaller is better. Ref data column gives the relationship of another data data select column

name. Row data column is MySQL in executing this query is expected from this data and the

read data line number. Row data column in all digital product can generally understand the

need to deal with the number of combination query. Finally, the extra data column is provided

with JOIN operation for more information about, for example, if the MySQL in executing this

query must create a temporary table, will be listed in the extra see usingtemporary.

In the CHAR and VARCHAR data type column definition index, the index can be the

length

limit

for

a

given

number

of

characters

(

this

number

must

be

less

than

the

field

the

maximum

allowed

number

of

characters

).

The

benefit

of

this

is

can

be

generated

in

a

relatively

small

size,

the

retrieval

speed

is

fast

compared

to

the

index

file.

In

most

applications, the database string data mostly a variety of names, the index length is set to 10 ~

15

characters

were

enough

to

narrow

your

search

to

a

few

data

records.

In

the

BLOB

and

TEXT data types to create index, to index length limits allowed by the MySQL; the maximum

index full text index text field on the general index can only accelerate to appear in the field

contents first string (i.e. field content retrieval operation initial characters ). If a field store is

composed of several, or even more words constituting the larger text, general index of little

use. This retrieval tends to form, the MySQL is very complex, if need to handle large volumes

of data, response time will be very long.

Most of today's application in the heart is the underlying database. In this case, brook no

delay in the design and implementation of the key business application data structure is very

important.

All had good modeling tools, such as MySQL workbench support forward engineering,

means that all use SQL code to create the database, and also can automatically write related

objects

and

correct

operation.

This

eliminates

the

developer

or

DBA

error-prone

and

time- consuming process.

Data design and its response database version control and management of life cycle, such

as the application, therefore, the most important is the data architect, database administrators,

developers.

9

To

understand

their

database

and

metadata

design

implementation

of

the

appropriate

change management needs. Link to certain information model driven method is optimal, but

access to data modeling and metadata object manual method can be run.

In the change management, may face data management professionals are facing the most

serious

challenge

is

one

of

the

existing

physical

database

design

in

the

successful

implementation of these complex changes.

Fortunately,

most

good

modeling

tools,

such

as

MySQL

workbench

can

alleviate

this

problem,

because

they

contain

the

synchronization

efficiency,

to

allow

the

database

administrator

or

developer

to

change

physical

data

modeling,

and

then

use

the

existing

physical database to synchronize these changes. The tool is all about execution effect analysis

or

generation

of

the

appropriate

database

code

all

the

work,

in

the

target

database

prior

to

implementation, easy to preview all changes.

In most of the tools, reverse engineering is also can be made very good - can modify a

data

modeling,

to

reflect

on

the

existing

physical

database

changes.

This

aspect

is

very

important, because it is often required to perform an emergency change database, but if the

change

management

or

reverse

engineering

modeling,

they

need

to

perform

the

update

to

reflect the current IT infrastructure.

Application

packaging

/

purchase

for

data

transfer

or

application

developers

know

in

what

form

to

use

the

underlying

database

often

very

difficult

black

box,

in

addition,

the

application package should be made to strengthen or other modifications, it is more important

to understand the effect of these changes, and to ensure that they are right.

On

the

application

management

packs

model

driven

method

can

greatly

simplify

the

process. Modeling is the visualization of data and complex database structure definition of a

perfect method. Through reverse engineering tool, very fast can be found in almost all good

modeling

tools,

database

management

and

developer

or

they

can

quickly

visualize

their

application

package

database

's

inner

workings,

and

understand

how

to

use

the

database.

Should

a

need

to

modify

the

database

or

add

operation,

modeling

tools

can

generate

the

analysis or generation code change.

Today's

enterprises

have

very

much

for

gripping

or

maintenance

of

data

consumers.

Some of them may be technical users, but may be many of them not, therefore, how to better

education and communication ways to access data is a great challenge.

In addition, in the large- scale development team they used data structures are the same.

They

often

need

to

understand

how

they

in

their

own

applications

to

coding,

so

that

it

is

suitable to access the target database.

10

Again,

the

model

for

technical

or

non- technical

personnel,

it

is

a

perfect

way

to

understand how the data is to be defined? Or how to access? Like the MySQL workbench so

good modeling tools can help them create modeling and export modeling pictures. Can also

create web based or based on text report to convert large modeling into readable form report

format.

MySQL

MySQL

mSQL

和他们自己的快速低级例程

(ISAM)

去连接

11

表格。经过一些测试后，开发 者得出结论：

mSQL

并没有他们需要的那么快和灵活。这

导致了一个使用几乎和

mSQL

一样的

API

接 口的用于他们的数据库的新的

SQL

接口的

产生，这样， 这个

API

被设计成允许为用于

mSQL

而写的第 三方代码更容易移植到

MySQL

。

< br>MySQL

这个名字是怎么来的已经不清楚了。基本指南和大量的库和工具带有前缀

“

my

”已经有

10

年以上，而 且不管怎样，

MySQL AB

创始人之一

Monty Wide nius

的女

儿也叫

My

。这两个到底是 哪一个给出了

MySQL

这个名字至今依然是个迷，包括开发

者在内也不知道。

MySQL

的海豚标志的名字叫 “

sakila

”

，它是由

MySQL AB

的创始人从用户在“海

豚命名”的竞赛中建议的大量的名字表中选出的。获胜 的名字是由来自非洲斯威士兰的

开源软件开发者

Ambrose Twe baze

提供。

根据

Ambrose

所说，

Sakila

来自一种叫

SiSwati

的斯威 士兰方言，也是在

Ambrose

的家乡乌干达附近的坦桑尼亚的

Arusha

的一个小镇

的名字。

与其他的大型数据库例如

Oracle

、

DB2

、

SQL

Server

等相比，

MySQL< /p>

自有它的不

足之处，如规模小、功能有限（

MySQL < /p>

Cluster

的功能和效率都相对比较差）等，但是

这丝 毫也没有减少它受欢迎的程度。

对于一般的个人使用者和中小型企业来说，

MyS QL

提供的功能已经绰绰有余，而且由于

MySQL

是开 放源码软件，因此可以大大降低总体

拥有成本。

LAMP

：

目前

Internet

上流行的网站构架方式是

LAMP

（