04 data type 1:string

# introduction to string

String type is the most basic data type of redis. A key corresponds to a value, and a key can store a maximum 512Mb.

String is binary secure.

# Common commands:

> set mykey "dang"

OK

> get mykey

"dang"

> set mykey "nihao" # multiple assignments will overwrite the original value

OK

> get mykey

"nihao"

> mset key1 1 key2 2 key3 e # multiple assignments

OK

> mget key1 key2 key3 # take multiple values

1) "1"

2) "2"

3) "e"

> setnx mykey 111I returned 0

(integer) 0

> setnx mykey2 111 # returns 1

(integer) 1

> get mykey2

"111"

# setnx if key exists, 0 is returned, and the existing value is not overwritten. The key is created directly if it does not exist.

> setex key6 30 yes # sets the expiration time, with the validity period in front and the value in the end

OK

> ttl key6 # gets the expiration time. If there is no expiration time,-1 is returned.

(integer) 25

> ttl mykey2

(integer)-1