Redis - learn five types of NoSQL

One , What is? NoSQL

 

NoSQL                

NoSQL = Not Only SQL ( not only SQL)

Relational database ： form , That's ok , Column

Non relational database in general , With web 2.0 The birth of the Internet ！ Traditional relational databases are hard to deal with web 2.0 Time ！

Especially large scale and high concurrency community ！ A lot of insurmountable problems have been exposed ,NoSQL In today's big data environment, it is developing very rapidly ,Redis It's the fastest growing , And it's a technology that we have to master right now ！

Many data types User's personal information , Social networks , Location . The storage of these data types does not require a fixed format ！ It can be expanded horizontally without many months of operation ！Map<String,Object> Use key value pairs to control ！

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NoSQL characteristic

decoupling ！

1, Easy to expand （ There's no relationship between the data , Good extension ！）

2, Maximum performance of big data （Redis Write in a second 8 Ten thousand times , Read 11 ten thousand ,NoSQL Cache record level of , It's a fine-grained cache , The performance will be relatively high ！）

3, Data types are diverse ！（ There's no need to design the database in advance ！ Take it and use it ！ If it's a table with a lot of data , A lot of people can't design ！）

4, Tradition RDBMS and NoSQL

Conventional RDBMS database

- Structured organization

- SQL

- Data and relationships exist in separate tables

- Operation operation , Data definition language

- Strict consistency

- Basic business

- .......

 NoSQL

- It's not just data

- There is no fixed query language

- Key value pair storage , Column store , Document storage , Graphic database （ social connections ）

- Final consistency

- CAP Theorem and BASE （ Different live ） Junior Architect ！

- High performance , High availability , Highly expandable

- .........

  understand ：3V+3 high ？？？  distributed file system FastDFS

Two ,NoSQL The four major categories of

        1, Key value pair storage   2, Column store   3, Document storage    4, Graphic database

KV Key value pair ：

•   Sina ：Redis
•   Meituan ：Redis + Tair
•   Ali , Baidu ：Redis + memecache

Document database （bson Format and json equally ）：

• MongoDB( Generally, we must master ）
•   .MongoDB Is a database based on distributed file storage ,C++ To write , It is mainly used to process a large number of documents ！
•   .MongoDB It's a gap between   Intermediate products between relational databases and non relational data ！MongoDB Yes no relational database has the most functions , Most like a relational database ！
• ConthDB

Column store database ：

• HBase
• distributed file system

  Graph relational database ：

        

•   He doesn't store graphics , It's about relationships , such as ： Circle of friends social network , Advertising recommendation ！
•  Neo4j , lnfoGrid;

Understand non relational databases

3、 ... and ,Redis introduction  

        Concept  

Redis What is it? ？

Redis （Remote Dictionary Server), Remote dictionary service ！

It's an open Use of source ANSI C Language writing , Support network , Log type that can be memory based or persistent ,Key-Value database , And provide multilingual API.

Redis Periodically, updated data is written to disk or changes are written to an appended log file , And on this basis to achieve master-slave（ Master-slave ） Sync .

Free and open source ！ It's the hottest thing right now NoSQL One of the technologies ！ Also known as structured database ！

Redis What can I do? ？

1, Memory storage , Persistence , In memory, power is lost , So persistence is important （rdb,aof)

2, Efficient , Can be used for caching

3, Publish subscribe system

4, Map information analysis

5, timer , Counter （ Browse volume ！）

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characteristic ：                       

1, A variety of data types   2, Persistence    3, colony    4, Business .....

  Be careful ：Wdinow stay Github Upload and download （ It's been a long time ！）

==Redis The recommendations are all in Linux Built on the server , We are based on Linux Study ！＝＝

Test link

Wｉｎｄｏｗ　 operation

 

  Remember a word ,Wｉｎｄｏｗ　 It's really easy to use , however Rｅｄｉｓ　 It is recommended that we use Lｉｎｕｘ To develop and use ！

The use of foundations

 Redis The default is 16 A database

Redis It's single threaded ！

  understand Redis It's very fast , Official expression ,Redis It's based on memory operations ,CPU No Redis Performance bottleneck ,Redis The bottleneck is based on the memory and network bandwidth of the machine , Now that you can use a single path to implement , Single thread is used ！ All use single thread ！

Redis Why is single thread so fast ？

The core ：redis Is to put all the data in memory , So using single thread to operate is the highest efficiency , Multithreading （CPU The context switches ： Time consuming operations ！！！）, For memory systems , If context switching is not used, it is the highest ！ Read and write many times in the same CPU Upper , In the case of memory , This is the best solution ！

Redis  Five data types ：

Redis -key

keys *           # View all key

set  name  liu   # set key

EXISTS  name  # Judge the current key Whether there is

move name 1     # Remove current key

EXPIRE name  10  # Set up key The expiration time of , The unit is seconds

ttl   name   # View expiration time

type    name   # View the current key A type of

String （ character string ）

set  key1  v1        # Set the value

get  key          # Get value

keys *        # Get all key

EXISTS  key1        # Judge a certain key Whether there is

APPEND key "hello"         # Append string , If at present key non-existent , Equivalent to setkey

STRLEN  key1         # Gets the length of the string

i++ operation

set  views  0         # Initial views are 0

incr  views          # Self increasing 1

decr  views        # Self reduction 1

INCRBY  views  10        # Set the self increment quantity

  String range   renge

set  key 1"liu"          # Set up key1 Value

GETRANGE  key1   0  3          # Intercepting string 【0,3】

GETRANGE  key1   0  -1         # Get all the strings

Replace  、

SETRANGE   key2  1  xx         # Replace the string starting at the specified position ！

setex  （set   with  expire）        # Set expiration time

setnx  （set   not    exist）        # non-existent   Set up

mset    k1 k2 k3 k4        # Set multiple values at the same time

mget   k1  k2  k3           # Get multiple values at the same time

msetnx   k1  k2   k3        # msetnx    It's an atomic operation , Or make it together , Or fail together ！

String Similar usage scenarios ：value In addition to our characters, it can also be our numbers ！

• Counter
• Count the number of multiple units uid：1 yes id
• Number of fans
• Object cache storage ！

List ：( data type )

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Basic data types , list

 

  stay Redis Inside , We can List Play into , Stack , queue , Blocking queues ！

be-all List The orders are based on L At the beginning

LPUSH  list   xxx           # Put one or more values , Insert to the head of the list

LRANGE  list  0  -1         # obtain list The median ！ You can also distinguish between fetched values

RPUSH list  righr           # Set one or more values , Insert into the list bit section （ Right ）

LPOP  list          # remove list The first element of

RPOP  list        # remove list Last element of

Lindex   list  1         # Get the first value of off-duty  

Lpush   list  xxx           # add value

Lrem  list   1 xxx           # remove   This 1 Is to remove several Can be repeated

Ltrim  mylist  12          # Intercept the specified length by subscript , This list Has been changed , Truncated. Only the intercepted elements are left ！

 Set  ( aggregate )

set The value in cannot be reread  

sadd  myset "hello"        # set Add... To the collection

SMEMBERS  myset        # View specified set All values

SISMEMBER   myset   hello        # Determine whether a value is in set Collection

scard  myset        # obtain set The number of content elements in the collection ！

srem  myset  hello        # remove set The specified element in the collection

SRANDMEMBER  myset        # Randomly select an element

spop   myset        # Delete some at random set The elements in the collection ！

 

 Hash( Hash )

Map aggregate ,key -<key-vlaue> When this value is a map aggregate ！ The nature and String There's no big difference in type , It's still a simple key-vlaue！

hset  myhash  field1  liu        #set A specific key -vlaue

hget  myhash   field1          # Get a field value

hmset  myhash  field1  hello  field2   world          # Get multiple field values

hgetall   myhash            # Get all the data

hdel  myhash field         # Delete hash Appoint key Field ！ Corresponding vlaue The value disappears ！

hlen  myhash        # obtain myhash The number of fields in the table

HEXISTS   myhash field1        # Judge hash Specifies whether the field exists ！

hkeys    myhash        # Just get all field

hvals   myhash          # Just get all value

 Zset( Ordered set )

zadd  myset  1   noe         # Add a value

zadd  myset   2   two  3  three           # Add multiple values

-----    How to implement sorting --------

zadd  salary  2500  xiaohong        # Add three users

ZRANGEBYSCORE  salary  -inf  +inf        # Show all users   From small to large

ZRANGEBYSCORE  salary   -inf  +inf   withscores        # Show all users with grades

ZRANGEBYSCORE  salary  -inf  2500  withscores   # Show salary less than 2500 Descending sort of employees

zrem salary   liu        # Remove the specified element from the ordered collection

zcard  salary        # Get the number of ordered sets