linux Download the redis database.
apt install redis
If the right is not enough, the right is directly raised.
sudo apt install redis-server
linuxEnable and stop service
service redis start
service redis stop
service redis restart
xshellEnter Linux
cd .. # Return to root directory ls # see file cd etc/
Well, it’s time to get to the point.
First, record.Connect, exit, switch databaseA command
Connect:redis：redis-cli Sign out:exit Switch database:select n
The database has no name, 16 by default, identified by 0-15, and the connection redis selects the first database by default (switched by select)
It has been said that redis has five big data structures. What do they have?
redisyeskey-valueData structure, each data is aKey value pair
The type of the key isCharacter string
Note: keys cannot be repeated.
There are five types of values:
String ——> Character string
Hash ——> Hash
List ——> list
set ——> aggregate
Zset ——> Ordered set
Now let’s start with a detailed look at what commands are commonly used for each data type.
stringtype
stringIt is the most basic type of redis, and a key corresponds to a value.
Sets the value of a given key. If key has stored other values, SET overwrites the old value and ignores the type.
Setting data:set key value
Set multiple sets of data:mset key value [key value..]
Setting values for multiple sets of keys is an atomic operation, either one set successfully or one set fails.
Returns the value of one or more key. If key does not exist, return nil, if key exists, but not string return nil
View data:get key
Appends the specified value to the end of the key, creates and assigns if the key does not exist, and returns the length of the appended string
Additional data:append key value
Returns the remaining survival time of key, -1 indicates permanent existence, and -2 does not exist.
ttl key
At the same time setting the key, setting the expiration time (in seconds) key will no longer be available after the expiration, will be automatically deleted by the system.
set key value ex seconds
set age 18 ex 20
Or setex key seconds value case: (setex sex 20 ‘male’)
Removes the lifetime of the specified key, returns 1 successfully, and 0 if the key does not exist or does not exist.
persist key
An additional order is added here.
Access to database:user db_name;
If you do not know if the database exists, please add if exists.
Global key operation
Commands applicable to five data types of redis
rename key newkey Rename
When key is the same as newkey or key does not exist, an error is returned. When newkey exists, it will be overwritten.
keys * # View all key del key # Delete the number of successful returns exists key # See if key exists or returns. type key # View key type expire key seconds #Set expiration date persist key #Remove expiration date
listtype
ListType is a list of strings that can be added or deleted at the head or tail of the list.
When inserting data, the elements are added to the list’s head or tail according to the insertion order.
If the key does not exist, Redis will create one for the key.
Add data:rpush key value [value…] Add data at the end
lpush key value [value…] Add data to the header
Returns the value of the element in the list. Index starts from 0 and returns null when index exceeds the index.
lindex key index
#View second
Look at the values of elements in index ranges.
View data:lrange key start stop
#View all values
Length of return list
llen key
Modify the data:lset key index value
AppointQuotation markMake a modification
Delete data:lpop key Delete the first on the left.rpop key Delete the first on the right.
Hashtype
It is a set of key values (key=> value) pairs. It is the mapping table of string type field and value.
user { name:juhao， age:18 }
user -> key(Key) name, age -> field (domain) juhao, 18 -> value (value)
Add data:
Set the field-value to the hash table. If the key does not exist, a new hash table will be created and reassigned, and the existing hash table will be overwritten.
hset key field value
View field values:
hget key field
Batch add:
hmset key field value field2 value2
View all value:
hvals key
View all field:
hkeys key
# Get multiple field
hmget key field[field...]
# Get all `field` and `value
hgetall key
# See a couple of key values.
hlen key
# Determines whether the specified field in the hash table exists, returns 1, and returns 0 if key or field does not exist.
hexists key field
# delete
hdel key field
Settype
The element is string type.
unordered set
The elements are unique and not duplicated.
sadd key member [member...] Added element
Add one or more member elements to the collection key. If member already exists, the element will be ignored.
# Returns the number of elements in set key.
scard key
# Get all the elements in the collection
smembers key
# There is a certain value in the judgement set.
Judge whether member exists in key and return to 0 or 1.
sismember key member
# delete
Remove one or more elements. Member that does not exist will be ignored, and the number of elements removed will be returned.
srem key member [member...]
# Random deletion
spop key
Removes and returns a random element in the collection, and returns to NULL when key does not exist.
zsettype
Similar to Set, the difference is that each member in Sorted has allocated one.Score (Score)Used to sort (ascending) members.
zsetThe members areOnlyBut the score (score) can be repeated.
# Add / modify
zadd key score member[ [score member] ..]
Set, exist, update
# See
zscore key member
View score value
# A member returned by index to key and withscores to display score.
zrange key start stop[withscores]
# Display all
# Returns the element of score in a given interval.
zrangebyscore key min max
# delete
zrem key member [member...]
Removes one or more elements in an ordered set and ignores if member does not exist.
# Delete elements whose index is in a given interval.
zremrangebyrank min max
# Delete elements of score in a given interval.
zremrangebyscore min max
Write here, redis finishing, order not to memorize, with more natural to remember.
It’s like writing sql, creating a new table, inserting insert into, and querying the select * from table.
Author: half smile and half smile
Blog link: https://www.cnblogs.com/lixy-88428977
Statement: This is a summary of bloggers’ learning experience, and the level is limited. If inappropriate, please correct me. If you think it’s not bad, you are welcome to reprint it. Please quote the author and provenance.