redis Data type of

redis It mainly supports five data types ：string、list、hash、set、zset

redis There are a lot of orders , We can look at the documentation , It can also be done through help View command ：

help @string
help @list
help @hash
help @set
help @sorted_set

For example, to perform ：help @string

string Operation commands and usage scenarios

string Common commands

1. String common operations

SET key value;     --  Store a string key value pair 
MSET key1 value1 key2 value2 ...  --  Batch store key value pairs 
SETNX key value    --  Store a string key value pair that does not exist 
MGET key1 key2 ...    -- Get key values in batch 
DEL key1 key2 ...    -- Delete key value pair 
EXPIRE key seconds   --  Set the expiration time of a key （ second ）

2. Atomic addition and subtraction

INCR key    --  take key Add one to the value stored in 
DECR key    --  take key Subtract one from the value stored in 
INCRBY key increment  -- take key The value stored in plus increment
DECRBY key decrement  -- take key Subtract from the value stored in decrement

Use scenarios

1. Single value cache
   It's simple , Namely SET key value and GET key
2. Object caching

• SET user:1 json_value( Object's json Format data )
  This cache is easy to operate , But modify a field in the object , You need to query the whole object cache , Deserialization , After the modification , Serialization is stored in .
• MSET user:1:name lisi user:1:age 18
  MGET user:1:name user:1:age

3. Distributed lock
   When multiple services operate , have access to SETNX command ：
   
   The service process that grabs the lock will be set successfully , If you don't grab it, it will return 0, Delete this key after the business logic processing is completed .
4. Counter ： The amount of reading
   

INCR article:id;
GET article:id;

5. web colony session share
   session+redis Realization session share
6. Distributed system global serial number
   INCRBY article 1000 Single acquisition 1000, Lifting performance
   

hash Operation commands and usage scenarios

Common commands

HSET key field value   --  Storage 
HGET key field         --  Get a field value 
HMSET key field1 value1 field2 value2 ...   --  Store multiple hash Key value pair 
HMGET key field1 field2 ...    --  Get multiple hash Key value pair 
HSETNX key field value  -- Storage one does not exist filed Value , Notice that it's not key
HDEL key field1 field2 ... --  Delete fields
HLEN key     --  return key in field The number of 
HGETALL key  --  Back to all field
HINCRBY key field increment  --  by field The value of the increase increment

Use scenarios

1. Store the object
   

HMSET user 1:name zhuge 1:balance 1888
HMGET user 1:name 1:balance

2. E-commerce shopping cart

• Add the goods

HSET cart:[ user id]  goods id  Number 

• Increase the quantity of goods

HINCRBY cart:[ user id]  goods id 1

• Total number of commodity categories

HLEN cart:[ user id]

• Delete item

HDEL cart:[ user id]  goods id

• Get all the shopping cart items

HGETALL cart:[ user id]

Example ：

hash And string Advantages and disadvantages compared with storage objects

1. advantage

• Data of the same kind is classified and consolidated , Easy to manage
• comparison string Operation consumes memory and cpu smaller
• Than string Save a space

2. shortcoming

• The expired function cannot be used in field On , Can only be used in key On
• redis Cluster architecture is not suitable for large-scale use

list Operation commands and usage scenarios

list Common commands

LPUSH key value1 value2 ...  --  Place one or more values from the left key in 
RPUSH key value1 value2 ...  --  Place one or more values from the right key in 
LPOP key   --  Pop up values from the left 
RPOP key   --  Pop up values from the right 
LRANGE key start stop  --  Returns a list of key The elements in the specified interval , The interval is offset by start and stop Appoint 
BLPOP key1 key2 ... [timeout] --  From many list Pop up element on the left in the middle , Timeout time timeout
BRPOP key1 key2 ... [timeout] --  From many list Pop up element on the right in the middle , Timeout time timeout

Use list Building data structures

Stack( Stack ) = LPUSH + LPOP
Queue( queue ) = LPUSH + RPOP
Blocking Queue( Blocking queues ) = LPUSH + BRPOP

Use scenarios

1. Micro-blog and official account message flow
   
   Big V Will send messages to subscribed fans ：
   for example ： user hiwei Of id1001
   The spare wheel said that the car pushed messages to fans :
   LPUSH msg:1001 1888
   MacTalk Also send messages ：
   LPUSH msg:1001 1999
   hiwei Get recent messages ：
   LRANGE msg:1001 0 4 – View the last five messages

set Operation commands and usage scenarios

Common commands

SADD key member1 member2 ...   --  towards set Put one or more in value
SREM key member1 member2 ...   --  from set Delete element 
SMEMBERS key       --  from set Get all elements from 
SCARD key          --  Get collection key The number of elements in 
SISMEMBER key member   --  Judge member Whether it exists in a set key in 
SRANDMEMBER key count   --  From the collection key Randomly selected count Elements , Don't delete elements .
SPOP key count          --  From the collection key Take them out randomly count Elements , Remove from collection .

set Operation ：

SINTER key1 key2 ...    --  Intersection operation 
SINTERSTORE  newKey  key1 key2 ...  --  take key The intersection of is stored in a new set newKey
SUNION key1 key2 ...    --  Union operation 
SUNIONSTORE  newKey key1 key2  ...  --  take key The union of is stored in a new set newKey
SDIFF key1 key2  ...   --- Subtraction operation 
SDIFFSTORE newKey key1 key2 ...     --  take key Save the difference set into a new set newKey

Use scenarios

1. Wechat lottery
   
   Users participate in the lottery ：
   SADD lottery 1001;
   SADD lottery 1002;
   SADD lottery 1003;
   View all lucky draw users ：
   SCARD lottery;
   Draw a lucky man ：
   SRANDMEMBER lottery 1;
   If it's a multiple draw , You can't win multiple awards , Then use SPOP lottery count
2. give the thumbs-up Collect scenes
   jams id=1001,tony Id=1002

• jams Yes tony give the thumbs-up ：
  SADD like:1002 1001
• tony Check the total number of likes ：SCARD like:1002
• View all likes ：SMEMBERS like:1002
• jams Cancel likes ：SREM like:1002 1001

3. Weibo, wechat and other social software attention models
   
   for example ：jams、mic、tony、lisi、wangwu
   jams Pay attention to the people jamsSet = {lisi,tony}
   mic Pay attention to the people micSet = {lisi,wangwu}
   be jams and mic People of common concern ：SINTER jamsSet micSet;
   jams People you may know ：SDIFF jamsSet micSet Then remove jams People of concern .

zset Operation commands and usage scenarios

Common commands

ZADD key [[score member]...]  --  Assemble in order key Add with score in member
ZREM key member1 member2 ...  --  Remove elements 
ZSCORE key member              --  Returns the element member The score of 
ZINCRBY key increment member   --  For the elements member The score of plus increment
ZCARD key                      --  Returns the number of elements in the collection 
ZRANGE	key	start stop        --  Positive order returns from start Subscript to stop Subscript elements 
ZREVRANGE	key	start stop        --  Return in reverse order from start Subscript to stop Subscript elements 

zset Set operations ：

ZINTERSTORE destination numkeys key [key ...]    --  Intersection calculation 
ZUNIONSTORE destkey numkeys key [key ...] 	--  Union calculation 

Use scenarios

Achieve leaderboards

1） Click on news
ZINCRBY hotNews:20190819 1 Guard Hong Kong
2） Top 10 on display day
ZREVRANGE hotNews:20190819 0 9 WITHSCORES
3） Seven days search list calculation
ZUNIONSTORE hotNews:20190813-20190819 7
hotNews:20190813 hotNews:20190814… hotNews:20190819
4） Show the top ten of the seven days
ZREVRANGE hotNews:20190813-20190819 0 9 WITHSCORES