Redis data type -string (string type)

String yes redis Most basic types , You can understand Memcached As like as two peas , One key Corresponding to one value.

String Type is binary safe , intend redis Of string Can contain any data , such as jpg Picture or serialized object .

String The type is redis Basic data types , One redis Middle string value At most 512M

Common command description ：

#=======================

#set get   del  append  strlen

#=======================

127.0.0.1:6379> set key wyt                # Set the value
OK
127.0.0.1:6379> get key                      # obtain key

"wyt"
127.0.0.1:6379> del key                       # Delete key
(integer) 1
127.0.0.1:6379> keys *                        # Check out all of key
(empty array)
127.0.0.1:6379> exists key                   # Make sure key Whether there is
(integer) 0
127.0.0.1:6379> append key wyt          # Yes, it doesn't exist key Conduct append, Equate to set  key  wyt 
(integer) 3                # Character length
127.0.0.1:6379> append key -lmp-hyd   # The existing string is append
(integer) 11               # Length from 3 Add characters to 11 Characters
127.0.0.1:6379> get key
"wyt-lmp-hyd"
127.0.0.1:6379> strlen key     # Gets the length of the string
(integer) 11
 

#================================

# incr  decr  Self increasing Self reduction   It has to be numbers to add and subtract +1 and -1

# incyby  decrby  The order will key The number stored in plus the specified value

#================================
127.0.0.1:6379> set browse 0                 # Set the number of views to 0
OK
127.0.0.1:6379> incr browse                   # Browse +1
(integer) 1
127.0.0.1:6379> incr browse                   # Browse +1
(integer) 2
127.0.0.1:6379> decr browse                  # Browse -1
(integer) 1
127.0.0.1:6379> incrby browse 10          # Browse +10
(integer) 11
127.0.0.1:6379> decrby browse -10        # Browse +10
(integer) 21
127.0.0.1:6379> decrby browse 10         # Browse -10
(integer) 11

#================================

# range 【 Range 】

# getrange Get the value in the specified range , similar between...and The relationship between . from 0 To -1 All

#================================

127.0.0.1:6379> set key wyt-lmp-hyd                # Set up key Value
OK
127.0.0.1:6379> getrange key 0 -1                    # Get all the values
"wyt-lmp-hyd"
127.0.0.1:6379> getrange key 0 3                       # Intercept part of string
"wyt-"
 

#=============================

# setrange  Set the value within the specified range , The format is setrange key value Specific value

#=============================

127.0.0.1:6379> get key                      
"wyt-lmp-hyd"
127.0.0.1:6379> setrange key 4 cby            # Replacement value
(integer) 11
127.0.0.1:6379> get key
"wyt-cby-hyd"

#=============================

# setex（set with expire） Key seconds  

# setnx （set if not  exist）

#=============================
127.0.0.1:6379> setex key2 60 yjy                 # Set expiration time
OK
127.0.0.1:6379> ttl key2                                # Check the time remaining
(integer) 56
127.0.0.1:6379> setnx mykey redis                # If it doesn't exist, set Successfully returns 1
(integer) 1
127.0.0.1:6379> set mykey gqy                        
OK
127.0.0.1:6379> setnx mykey gqy                # If it exists, set Failure to return 0
(integer) 0        
127.0.0.1:6379> get mykey
"gqy"

#=======================

#  mset     mset The command is used to set one or more at the same time key-value Yes

#  mget     mget Command if all （ One or more ） Given key value  

#                If given key Inside   There is a certain key non-existent So this key Return special value nil

#  msetnx      When all key All set successfully   return 1

#                    If all given key All settings failed （ At least one key Already exist ） Then the return 0  Atomic manipulation

#=======================

127.0.0.1:6379> mset k1 wyt k2 lmp k3 hyd k4 yjy k5 gqy k6 syy
OK
127.0.0.1:6379> keys *
1) "browse"
2) "k5"
3) "key"
4) "k3"
5) "k4"
6) "k2"
7) "k1"
8) "mykey"
9) "k6"
127.0.0.1:6379> mget k1 k2 k3 k4 k5 k6
1) "wyt"
2) "lmp"
3) "hyd"
4) "yjy"
5) "gqy"
6) "syy"
127.0.0.1:6379> mget k10
1) (nil)
127.0.0.1:6379> msetnx k10 by k15 yy   # Atomic operation
(integer) 0
127.0.0.1:6379> get k15
（nil）

# Traditional object caching

set user:1 value(json data )

# Can be used to cache objects

127.0.0.1:6379> mset user:1:name wyt user:1:age 2
OK
127.0.0.1:6379> mget user:1:name user:1:age
1) "wyt"
2) "2"

#=============================

# getset  （ First get stay set）

#=============================

127.0.0.1:6379> getset db mongodb                # There is no old value return nil
(nil)
127.0.0.1:6379> get db
"mongodb"
127.0.0.1:6379> getset db redis                       # Return old value mongodb
"mongodb"
127.0.0.1:6379> get db
"redis"

String The data structure is simple key-value type ,value In fact, it can be more than String, It can also be numbers .

routine key-value Cache application ：

Regular count ： Number of microblogs , Number of fans, etc .