String type (string)

A , Features

1, strings, numbers, are stored into a string
2 to a binary stored in memory

Two , the string of commands

You must master command

# 1. Set a value-key 
　　SET key value
 # 2. Get the value of key 
　　GET key
 # then set (NX) 3. When the key is not present 
　　SET key value NX
 # 4. Set expiration time (EX) through the date on automatically destroyed ex px milliseconds seconds 
　　sET value ex seconds The Key
 # 5. The plurality of simultaneously-value Key 
　　MSET VALUE1 key1 key2 value2 value3 key3
 # 6. The multiple simultaneously acquired value-Key 
　　mget key1 key2 key3

As understanding of command

# 1. Obtain length 
　　strlen Key
 # 2. Get the specified range slice content 
　　GetRange Start Key STOP
 # 3. Starting index, value replaces the original content 
　　SetRange Key index value
 # 4. value of additional spliced value

Two numerical operation

1. String type numbers (must master)

# Integer operations 
INCRBY key step size (value + ?) 
DECRBY Key steps (value - ?) 
INCR Key: + 1 operation 
DECR Key: - 1 Operation
 # scenarios: someone follows you on vibrato, is not it can be used INCR then, if attention is not canceled can DECR 

# floating-point operations: the first type to digital, and then to add and subtract, you can not use the append 
incrbyfloat the STEP Key

2. Key naming convention

mset wang:email [email protected]

127.0.0.1:6379> mset wang:email [email protected] guo:email [email protected]
OK
127.0.0.1:6379> mget wang:email guo:email
1) "[email protected]"
2) "[email protected]"
127.0.0.1:6379>

3.string data type Notes

# Key value, in Principle 
1 , Key value not too long, memory consumption, and the key to find such a high computational cost in the data
 2 , should not be too short, poor readability
 # value 
1, a string type the value of the content can store up to 512M

string Command Summary

# String operations 
. 1 , SET value Key
 2 , Key SET value NX
 . 3 , GET Key
 . 3 , MSET
 . 4 , mget
 . 5 , SET Key seconds The value EX
 . 6 , strlen Key 
 # digital operation 
. 7 , step incrby Key
 . 8 , step decrby Key long
 . 9 , incr Key
 10 , Key DECR
 . 11, incrbyfloat Key number # (number may be positive or negative) 
# set expiration time in two ways 
# manner a 
1, set key value. 3 EX # mode two 
. 1 , sET Key value
 2, The expire. 5 Key # s 
3, pexpire key 5
# Ms 
# view survival 
ttl Key
 # delete expired 
the persist Key
 # returns the old value and the new value is set (if the key does not exist, it is created and assigned) 
getset Key value

General command applies to all data types

# Switch library (value number of digital db0-db15 between 0-15) 
    the SELECT number
 # View keys 
    keys * keys expressions * 　　# keys * keys user * (the beginning of the user key) 
# key to type 
    the TYPE Key
 # key is present 
    key EXISTS
 # delete key 
    del key
 # key to rename 
    the rename key newkey
 # Clear all the data in the current library (caution) 
    flushdb
 # Clear all the libraries in all the data (caution) 
    flushall

Exercise:

1, the library to view all the keys db0
　　SELECT 0
　　Keys *
2, provided bonds trill: username user001 corresponding value, and see
　　SET trill: username 'user001'
. 3, obtaining trill: username length value
　　strlen trill: username
. 4, disposable set trill: password, trill: gender, trill: fansnumber and view (custom value)
　　MSET TRILL: password '123456' TRILL: Gender 'm' TRILL: 10 fansnumber
　　mget TRILL: password TRILL: TRILL Gender: fansnumber
. 5, View key trill: score the existence of
　　eXISTS trill: score
6, an increase of 10 fans
　　incrby the TRILL: fansnumber 10
7, increased by 2 fans (one by one plus)
　　incr the TRILL: fansnumber
　　incr the TRILL: fansnumber
8, there are three fans unfollowed you the
　　decrby the TRILL: fansnumber 3
9, fans have a concern you cancel the
　　DECR the TRILL: fansnumber
10, thinking, thinking, thinking ..., clear the current library
　　flushdb
11, after ten thousand thinking, clear all libraries
　　flushall

Data Type: string type (string)