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origin --- Hang out in the blog Garden

The other day , At some point QQ The group saw a message “XXX The hotel opens rooms XXXBTXX thunderbolt BT download ”, At that time, I was browsing with a mind of ten lines at a glance , When the eyes pass ,

First reaction I think too much ~ Thought it was XX seeds ( You'll see ~), But not interested .

Until I went back to the blog park , See one of the most commented articles :

See how inefficient multithreading is ! - Zhang Haohua - Blog Garden

http://www.cnblogs.com/zhhh/p/3385751.html

So click in . At this time , I just remember , At that time, I thought too much ......

Turned out to be 2000w A database of data records of housing development , After browsing the article , I say yes to this 2000w Interested ! therefore , This is the birth of this article .

Bond --- Search engine to pull the line

After reading the article mentioned above , I decided to play too , But the gardener is a little “ lazy ” 了 , No database and Demo download . ok , At this time, we need to play the search ability , Several searches , And finally Google To help ( Many of the links found by Baidu have been harmonious ~). ( reminder : Recently, the higher authorities have carried out strict checks on water meters , You need to be careful when you spread things ~).

An hour passed ,1.7GB Finally, the compressed file is downloaded :

C:\[fuliba.net] A hotel 2000W data ( Decompression password :sjisauisa It's data 8 It's comfortable. Good sjjss).rar
 file size :1834815332 byte 
 Date of creation :2013 year 10 month 24 Japan  15:38:55
 Hash value (MD5):091AAC2B45D76CE1CD4248E7FFF1C00E

After decompressing , about 8GB many .

Nothing is as good as nothing

In the face of tens of millions of data level database files , Let's take a look at my local configuration information first :

  Operating system name     Microsoft Windows  Ultimate
  Operating system core (Kernel) type     Multiprocessor Free (-bit)

 Microsoft SQL Server 2008R2
 Microsoft SQL Server Management Studio                        10.50.1600.1
 Microsoft Analysis Services Client Tools                        10.50.1600.1
 Microsoft Data Access Components (MDAC)                        6.1.7601.17514
 Microsoft MSXML                        3.0 5.0 6.0
 Microsoft Internet Explorer                        9.10.9200.16686
 Microsoft .NET Framework                        2.0.50727.5472
 Operating System                        

  Hardware overview  

 CPU:         Intel  Core i3-380M ( Dual core )
  a main board :         Founder  R410CP ( Intel  HM55 (IbexPeak-M DH))
  Memory :         GBytes
  The graphics card :        ATI (PARK PRO/XT GL)
  Hard disk :         Toshiba corp.  MK3265GSX

  Processor information 

  processor :        Intel(R) Core(TM) i3 CPU       M   @ .53GHz
  Running speed :        2533.3 MHz
  The core / Threads :         Dual core ,  Four threads 
  Core code :        Arrandale SV
  Power waste :        25.0 W
  Socket :        Socket G1 (rPGA988A)
  First level cache :         Instructions :  x  KB,  data :  x  KBytes
  Second level cache :         Integrate :  x  KB
  Three level cache :         MB
  characteristic :        MMX SSE SSE SSE SSSE SSE4. SSE4. EMT64 VT EIST TM1 TM2

  Motherboard information 

  Motherboard manufacturer :         Founder 
  Motherboard model :         Founder  R410CP
  Chipset :         Intel  HM55 (IbexPeak-M DH)
  Motherboard slot :        2xPCI Express x1, 6xPCI Express x2, 1xPCI Express x16
 USB Support :        v2.
 PCI
 BIOS edition :        V1.
 BIOS date :        

  Memory information ( A total of : GBytes)

  Memory module 1:
  Memory size :         MB
  Memory type :        DDR3 SDRAM
  Manufacturer :         samsung 
  Date of manufacture :        2010 In the first 39 Zhou 

  Memory module 2:
  Memory size :         MB
  Memory type :        DDR3 SDRAM
  Manufacturer :         samsung 
  Date of manufacture :        2012 In the first 1 Zhou 

  Graphics information 

  Graphics chips :        ATI (PARK PRO/XT GL)
  Memory size :         MB of DDR3 SDRAM
  Graphics card model :        ATI (PARK PRO/XT GL) [ Acer ]
  The graphics card BIOS edition :
  frequency :        157.0 MHz

  Store information 

  Memory 1:
  controller :        Serial ATA 3Gb/s
  model :         Toshiba corp.  MK3265GSX
  Capacity :        , MB ( GB)
  speed :         RPM
  cache :         KB
 NCQ function :         Support ,
 S.M.A.R.T.:         There is ,  Turn on 
 48bit LBA:         Support ,  Turn on 
  working hours :        7088 Hours  

Tester configuration information

It should be OK ? What's a little bit awkward is in the 32 Bit system is forced to use it ( Crack -- How to map )6GBytes Of memory , ha-ha , Will there be any future trouble ?


Most of the database files I learned to use are MDF Format , You can use it by attaching it directly , But now after decompression, it's .bak Format , It's a backup , So you can't attach it in an additional way ,

It's about using 【 Restore 】 The way , Pictured :

You can also try to restore by command bak File and build it into a new database ,( For reference only , No practice )

/*
 The backup data DB  To .bak file . And then use this bak File restore a new database DBTest.
*/
USE master
BACKUP DATABASE DB
  TO DISK = 'g:\DBBack0930.bak'
RESTORE FILELISTONLY
  FROM DISK = 'g:\DBBack0930.bak'
RESTORE DATABASE DBTest
  FROM DISK = 'g:\DBBack0930.bak'
  WITH MOVE 'DBTest' TO 'E:\Program Files\Microsoft SQL Server2005\Data\DBTest.mdf',
  MOVE 'DBTest_log' TO 'E:\Program Files\Microsoft SQL Server2005\Data\DBTest_log.ldf'
GO

OK! Let's start restoring , Click OK , I was stunned , The machine seems to be stuck , The state of restoration has been (2 Within minutes ) yes 0,

The mouse cursor becomes a busy circle , The system is too laggy. ,( Khan, ~~ Students in school , I haven't seen any big scenes , Stunned by the progress , Don't laugh !),

Another minute passed , Finally, there's a response , Percentage display of status 20%+, Step by step 6% Increasing from left to right , Not in “ stuck ” Status quo ,

A few minutes later , Finally done . before , Addition of classroom exercises , Restoring files is almost always done in seconds , There's almost no concept of time to wait ,

It can be said that this time I saw what mass is ( however , But among you old birds ,2000w, Maybe it's just Canghaiyi Millet (sù)) data .


Restore successful ! So I was anxious to check her in my heart right away , Is it on the list . think little of , Here comes one SQL sentence :

select * from dbo.cdsgus where Name=' The goddess '

Oh , I was shocked again ! Omit here ...... word ,

slow , Don't think too much , It's not that we found the list of goddesses , It's the computer that's stuck again , It's just that the query is still executing , In limine , I thought the memory was too small ,

CPU It's too bad ,Ctrl+Alt+Del Call the task manager out :

The picture above tells me , No CPU, Memory error , Just then , A shining red star caught my attention ~~

Yes , You guessed it ! It's the reading and writing status indicator of the hard disk , It's flashing fast , At ordinary times , It only flashes occasionally . therefore , I once again transferred from task management 【 Resource monitor 】 To see what's going on ,

“ Get stuck ” The reason for this has been found , Above , Not much said . before , Rarely pay attention to hard disk IO problem , After all, often Copy There are not many opportunities for big files . This time, , I'm really focused on hard drives IO problem , I'm here to give myself and you to IO A strange friend added :

Reading and writing IO(Read/Write IO) operation

Disk is used to access data for us , So when it comes to IO During operation , There will be two corresponding operations , When saving data, it corresponds to writing IO operation , When you get data, it's read IO operation .

Single IO operation When the controller that controls the disk receives a read from the operating system IO When operating instructions , The controller will send a read command to the disk , At the same time, the address of the data block to be read is passed to the disk ,

The disk then passes the read data to the controller , And the controller returns it to the operating system , Finish a write IO The operation of ;

alike , One writes IO It's similar to , The controller receives the IO Instructions for operation and data to be written , And pass it to disk , The disk passes the result of the operation back to the controller after the data is written ,

Then the controller returns it to the operating system , Finish a write IO The operation of . Single IO Operation refers to the completion of a write IO Or reading IO The operation of .

  For often do network , On the server side ,I/O Bad reflection to the website is that the website page loading is slow 、 card 、 Slow to read database ,

It even causes the page to open overtime .

About IO Recommended articles on bottleneck handling :
Understanding Disk I/O - when should you be worried?
http://blog.scoutapp.com/articles/2011/02/10/understanding-disk-i-o-when-should-you-be-worried

In beta DBA » IO One of the system performance : Several indicators of performance
http://www.dbabeta.com/2009/io-performence-01_several-concepts.html

Waiting for the 200 many s, Finally, there is a result :

ha-ha , After all, there was no goddess's name .

Face it 2000w, One select * from XXX It makes me blush , I'm thinking about who's next , An idea in my heart caught me .

You can't toss the hard disk like this , Vulnerable .....


Rake yard for school students --- We can practice and test the theoretical knowledge we usually learn

【 background 】

Usually the class practice project , The number is mainly dozens , I don't want to be bored to set up tens of thousands of non real data to test .

【 actual combat 】

You have to wait to query a piece of data 200 many s, Do you have such a waste of time ? Just then , The theoretical knowledge we usually learn will come in handy -----【 Indexes 】

【 Four or two thousand catties --- Index to help 】

It's mentioned above , Execute statement :  select * from dbo.cdsgus where Name=' The goddess '  It took 200 More than a second ,

If there's only one result , Let's have a guess :

select top 1 * from dbo.cdsgus where Name=' The goddess '  How long will it take ?  -- Let's leave it to you to practice .

ok , In order to find her quickly , We call the field name Name Index :

Create Index Index_ByName on dbo.cdsgus(Name)  -- Because there are so many records , Indexing is slow , Time consuming :03:49

The above note says that indexing takes 209 second , What does it do behind its back ? Query again after indexing , Why did it make me so shocked again ?

At this time , Go to query again and execute the same query , Let's guess how long it took this time , Compared with the time consumption just now , I'm stunned again .

Usually, we can hardly realize the influence of index on retrieval speed in class practice , This time, it can be called practice , I understand !

There is no such thing as a free lunch , Index can play an important role in our retrieval speed , that , There must be a price to pay . You know what the cost is ?

In class , There are only a few theoretical remarks about the disadvantages of index :

 First of all , Creating and maintaining indexes takes time , This time increases with the amount of data .
 second , Index needs to occupy physical space , In addition to the fact that data tables occupy data space , Each index takes up a certain amount of physical space , If you want to build a clustered index , So much more space is needed .
 Third , When adding data in the table 、 When deleting and modifying , Index also needs dynamic maintenance , This reduces the speed of data maintenance . 

It has been proved in practice , Even if it's done , Because it's dozens , 100 data items , I can't feel it .

This time, it can be said that it has been put into practice .

For the above shortcomings ,

Article 1 with a ,209s I've learned a lot about time consuming .

Second , Need to take up physical space , Please see the following data comparison :

 Field not specified Birthday File size before indexing :
  :     ,,, shifenzheng.mdf
  :        ,, shifenzheng_1.LDF

 File size after indexing :
  :     ,,, shifenzheng.mdf
  :        ,, shifenzheng_1.LDF

For the third one , There is no practice here , After all, this database is used to look up data , From the first , We can infer the third from the second .

For fields that are often used for queries , The advantages of indexing outweigh the disadvantages , Review the :

 First of all , By creating a unique index , Ensure the uniqueness of each row of data in the database table .
 second , Can greatly speed up the retrieval of data , This is also the main reason to create indexes .
 Third , Can speed up the connection between tables , In particular, it is of great significance to realize the referential integrity of data .
 Fourth , Using grouping and sorting   Clause for data retrieval , It can also significantly reduce the time of grouping and sorting in queries .
 The fifth , By using index , During the process of query , Using the optimize hide tool , Improve system performance .

With the index , It's much more convenient for us to inquire , Do you want to know our DuDu Are you shortlisted ? Let's watch :

select * from dbo.cdsgus where Name=' dudu '
-- Time consuming  4s
--(393 row(s) affected)

Limited space , Also prevent harmony , I'm not going to publish the data here , Hee hee ! Think about it , There are many people with the same name in China !

Because we are here to query the database directly , There is no application layer interface , Such as Winform,WebFromt etc. , If you do that ,

Consider the storage process , Efficient paging query, etc , So I'm just going to use SQL Statement demonstration .


Baoding jieniu --- Analysis table structure design

It starts from pragmatism , Is take the : download ---》 Restore ---》 Query results , Such a route , Not from the bottom at all , Think about the structure .

Um. , Now let's calm down , Take a look at the design of this watch ,

Column_name  Type Computed  Length    Prec    Scale   Nullable TrimTrailingBlanks    FixedLenNullInSource    Collation
Name                            yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
CardNo                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Descriot                        yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
CtfTp                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
CtfId                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Gender                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Birthday                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Address                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Zip                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Dirty                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
District1                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
District2                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
District3                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
District4                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
District5                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
District6                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
FirstNm                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
LastNm                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Duty                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Mobile                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Tel                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Fax                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
EMail                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Nation                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Taste                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Education                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Company                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
CTel                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
CAddress                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
CZip                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Family                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
Version                          yes    (n/a)    (n/a)    Chinese_PRC_CI_AS
id                no    (n/a)    (n/a)    NULL

It can be seen that the author is very lazy , Except for the primary key id, All other fields are used nvarchar, length 4000 To cope with , Actually, when you see this , I'm a little skeptical about the authenticity of the data ( Is it generated at will ) Of .

  And  ,  Between . The storage size of a byte is twice the number of characters entered . The character length of the input data can be zero 

Verify data authenticity ( I hope more friends can provide accurate ways )

Start with questions , I used this statement to query :

select  * from dbo.cdsgus where Address like 'XX province XXx City XX The town of XX The village %'   --X Name of representative place 

ha-ha , I really found some familiar friends , Let it be true . Or the original database has been processed 、 After finishing , Just create a table, save it, and then back it up and put it on the Internet .

( I wondered , After the entire backup file is restored, there is only one table ~)

Get back to business , Let's see :

Name    Owner     Type          Created_datetime
cdsgus  dbo       user table      

The author is a night owl , Take a look at the creation date : ::21.120.

ID Automatic increase column :

Identity    Seed    Increment    Not For Replication
id                     
index_name        index_description                  index_keys
Index_Birthday    nonclustered located on PRIMARY     Birthday
Index_ByAddress    nonclustered located on PRIMARY    Address
Index_ByName    nonclustered located on PRIMARY       Name
PK_cdsgus    clustered, unique, primary key located on PRIMARY    id

Originally only id Default primary key index ,Name,Address,Birthday I added it later .

constraint_type        constraint_name    delete_action    update_action    status_enabled
PRIMARY KEY (clustered)    PK_cdsgus    (n/a)    (n/a)    (n/a)    (n/a)    id

ok! We've finished reading the table field structure , Even though this database has only one table , Only one is set in the table id Primary key . But from the results ,

We can see that , In fact, several fields are used as foreign keys ,

As shown in the figure below :District1--6,family,id etc. .

Now that we have the foreign key , So there should be other tables , I hope someone can provide it , ha-ha .


Powerful and unconstrained style --- data mining 、 analysis 、 utilize

The data is , Except for a few exercises select What else can a sentence do ?

This is the time , It's time to give full play to our ideas , Have a look , Think about what's in it ?

Because of the authenticity of the data , And the ID number , Email address , Phone number ...... Hey , Think of! ? Don't use it to do bad things !

  • When the swindlers get the data , May be used to send blackmail messages ;
  • They may be used to spread advertisements ;
  • Data mining experts may be used to understand the number of people staying in hotels around the world , Age stage , Distribution time range, etc .
  • ......

Let's also learn to analyze ,( Everyone in the garden should have been in contact with sql sentence , The following is direct sampling and analysis )

Regional distribution :( To the north of , On , Take Guang as an example )

select  count(*) as ' Beijing ' from dbo.cdsgus where Address like ' Beijing %'
select  count(*) as ' Shanghai ' from dbo.cdsgus where Address like ' Shanghai %'
select  count(*) as ' guangdong ' from dbo.cdsgus where Address like ' guangdong %'

Conclusion : Leave it to you to think ......


Age distribution :

select  count(*) as '00 after ' from dbo.cdsgus where Birthday like '20%'
select  count(*) as '1990 after ' from dbo.cdsgus where Birthday like '199%'
select  count(*) as '1980 after ' from dbo.cdsgus where Birthday like '198%'
select  count(*) as '1970 after ' from dbo.cdsgus where Birthday like '197%'
select  count(*) as '1960 after ' from dbo.cdsgus where Birthday like '196%'
select  count(*) as '1950 after ' from dbo.cdsgus where Birthday like '195%'
select  count(*) as '1940 after ' from dbo.cdsgus where Birthday like '194%'
select  count(*) as '1930 after ' from dbo.cdsgus where Birthday like '193%'
select  count(*) as '1920 after ' from dbo.cdsgus where Birthday like '192%'
select  count(*) as '1910 after ' from dbo.cdsgus where Birthday like '191%'
select  count(*) as '1900 after ' from dbo.cdsgus where Birthday like '190%'
select  count(*) as '1800 after ' from dbo.cdsgus where Birthday like '180%'

result :80 As the main force , Are you in it ?

Similar fuzzy query , You can be flexible , For example, query whether the customer is a mobile user or a Unicom user ( According to the mobile phone number before N position ), Email, domain name, etc .

More visual modeling data mining , analysis , I recommend you to see :

A simple analysis of the 20 million leaked data on the Internet - Deep blue - Blog Garden
http://www.cnblogs.com/studyzy/p/3388887.html
Here , Borrow some data :

Age distribution

Province Distribution

Province Hotel ranking Population ranking Up the list
jiangsu 1 5 4
Shanghai 2 24 22
Beijing 3 26 23
Shandong 4 2 -2
guangdong 5 1 -4
Zhejiang 6 10 4
Henan 7 3 -4
hubei 8 9 1
liaoning 9 14 5
shaanxi 10 16 6
hebei 11 6 -5
fujian 12 17 5
shanxi 13 18 5
anhui 14 8 -6
Black Dragon 15 15 0
tianjin 16 27 11
sichuan 17 4 -13
jiangxi 18 13 -5
hunan 19 7 -12
Ji Lin 20 21 1
Inner Mongolia 21 23 2
Chongqing 22 20 -2
guangxi 23 11 -12
gansu 24 22 -2
guizhou 25 19 -6
xinjiang 26 25 -1
yunnan 27 12 -15
hainan 28 28 0
ningxia 29 29 0
qinghai 30 30 0
Tibet 31 31 0

Mobile phone number segment distribution

139 1399857
138 1230530
135 782764
136 778188
137 683742
186 581451
159 456526
158 434760
133 356135
150 324798

front 10 Ranking of big mailbox domain names :

@qq.com 611842
@163.com 594392
@126.com 274512
@hotmail.com 203237
@sina.com 151798
@yahoo.com.cn 101692
@gmail.com 96346
@139.com 67565
@sohu.com 50179
@yahoo.cn 31274

Suggest

This concludes the query example , Now many people on the Internet use this database as a data source , Can pass Web Page for query ,

But I used a few, which are not ideal , It's pitifully slow , Sometimes I wonder if he has set up the corresponding index , The biggest limitation is : Only through ID card , Check your name .

For you as a programmer , Do you accept such low authority ?

therefore , It is suggested that you should find this document when you are free , Test... Locally , Recommended to all students , It can be used to practice multi data query , optimization problem .

Of course , If a friend has the resources , Build a Web page , You can input sql It's even better to query by the command .


Finally, let's take a picture of the transformation of data value :

We now have the database , It arrived directly Processing workshop This floor , How to explore , It depends on your creativity .


summary

Ever since I handed it in at school 210 Yuan fee test a so-called Database Engineer Certificate ( The school requires to take the exam , But it's not very technical ),

After that, they had less contact SqlServer Database , In a moment ,10 The end of the moon , I'll be preparing for my internship in a while , I'm still a student .

This time with this 2000w To review the relevant basic knowledge ,

disk IO Performance issues , The data backup , recovery , Indexes , Fuzzy query , Function call , Big data analysis , mining , Utilization, etc .

throw away a brick in order to get a gem --- Looking forward to bright comments

This article , It just represents a student's first test 2000w The simple practice of the database of records , speak generally , The conclusion , It is inevitable to be frivolous 、 decisive .

deficiencies , I hope you can give me more guidance , Correct the wrong argument of this article .

【 database 】_ from 2000W Thinking caused by multiple housing data 、 practice ---- A reality for students at school 【 Rake yard 】, The classmates , Let's start a great experiment . More articles about

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