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Redis学习02之String & Database

  • 2020/06/27
  • Redis
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Redis支持5种数据类型，这里记录第一个String字符，Redis中的字符串和其它编程语言或键值库功能相似，函数丰富方便，字符串的值可以存储3种类型的值：字节串、整数、浮点数。KEY可以是数字、大小写字母、下划线或中文， Value 有空格要以引号括起。如果value是整数或符点数可以对其自增、减操作。可以增、删、改、查等操作, KEY 和Value可以是中文，但是key是中文是使用keys 列出键时中文为unicode码。

String SET/GET

127.0.0.1:6379> ping
PONG
127.0.0.1:6379> set 1 a
OK
127.0.0.1:6379> get 1
"a"
127.0.0.1:6379> set keyname valuename
OK
127.0.0.1:6379> get keyname
"valuename"
127.0.0.1:6379> set name "weejar zhang"
OK
127.0.0.1:6379> get name
"weejar zhang"

如果KEY存在则不更新

127.0.0.1:6379> get name
"weejar zhang blog .com"
127.0.0.1:6379> set name "anbob.com" NX
(nil)
127.0.0.1:6379> get name
"weejar zhang blog .com"

多个KEY Mget

127.0.0.1:6379> keys *
1) "blog"
2) "name"

127.0.0.1:6379> mget name blog
1) "weejar"
2) "anbob.com"

127.0.0.1:6379> getrange blog 4 -1
"b.com"

127.0.0.1:6379> getrange blog 4 -2
"b.co"

整数、浮点加减

127.0.0.1:6379> set age 30
OK
127.0.0.1:6379> get age
"30"
127.0.0.1:6379> incr age
(integer) 31
127.0.0.1:6379> incrby age 3
(integer) 34
127.0.0.1:6379> decr age
(integer) 33

检索模糊

127.0.0.1:6379> set 名字 张维照
OK
127.0.0.1:6379> get 名字
"\xe5\xbc\xa0\xe7\xbb\xb4\xe7\x85\xa7"
127.0.0.1:6379> keys *
1) "1"
2) "keyname"
3) "name"
4) "age"
5) "\xe5\x90\x8d\xe5\xad\x97"

127.0.0.1:6379> keys name
1) "name"
127.0.0.1:6379> keys na
(empty array)
127.0.0.1:6379> keys na*
1) "name"
127.0.0.1:6379> keys na?e
1) "name"
127.0.0.1:6379> keys nam[ed]
1) "name"
127.0.0.1:6379> type name
string

127.0.0.1:6379> type age
string
127.0.0.1:6379> exists name
(integer) 1
127.0.0.1:6379> keys 1
1) "1"

改名和删除

127.0.0.1:6379> rename 1 key1
OK
127.0.0.1:6379> del key1
(integer) 1
127.0.0.1:6379> keys *
1) "keyname"
2) "name"
3) "age"
4) "\xe5\x90\x8d\xe5\xad\x97"
127.0.0.1:6379> flushdb
OK
127.0.0.1:6379> keys *
(empty array)
清空所有
127.0.0.1:6379> flushall

追加和截取

127.0.0.1:6379> set name "weejar zhang"
OK
127.0.0.1:6379> get name
"weejar zhang"
127.0.0.1:6379> append name " anbob.com"
(integer) 22
127.0.0.1:6379> get name
"weejar zhang anbob.com"
127.0.0.1:6379> getrange name 13 17
"anbob"
127.0.0.1:6379> setrange name 13 "blog "
(integer) 22
127.0.0.1:6379> get name
"weejar zhang blog .com"

127.0.0.1:6379> get name
"anbob.com"

127.0.0.1:6379> getrange blog 4 -1
"b.com"

127.0.0.1:6379> getrange blog 4 -2
"b.co"

getrange在是从原来的substr改名，在python redis中依旧保留两种。

大小写互换

127.0.0.1:6379> set chr h
OK
127.0.0.1:6379> get chr
"h"
127.0.0.1:6379> setbit chr 2 0
(integer) 1
127.0.0.1:6379> get chr
"H"
127.0.0.1:6379> setbit chr 2 1
(integer) 0
127.0.0.1:6379> get chr
"h"

生命周期

127.0.0.1:6379> get name
"weejar zhang blog .com"
127.0.0.1:6379> ttl name
(integer) -1
127.0.0.1:6379> expire name 10
(integer) 1
127.0.0.1:6379> ttl name
(integer) 8
127.0.0.1:6379> ttl name
(integer) 7
127.0.0.1:6379> ttl name
(integer) 6
127.0.0.1:6379> ttl name
(integer) 5
127.0.0.1:6379> ttl name
(integer) -2
127.0.0.1:6379> get name
(nil)
127.0.0.1:6379> set name "anbob.com" EX 10
OK
127.0.0.1:6379> ttl name
(integer) 9
127.0.0.1:6379> ttl name
(integer) 7

改为永久

127.0.0.1:6379> persist name
(integer) 1
127.0.0.1:6379> ttl name
(integer) -1

随机KEY

127.0.0.1:6379> set age 30
OK
127.0.0.1:6379> keys *
1) "age"
2) "name"
127.0.0.1:6379> randomkey
"age"
127.0.0.1:6379> randomkey
"age"
127.0.0.1:6379> randomkey
"age"
127.0.0.1:6379> randomkey
"name"
127.0.0.1:6379> randomkey
"name"

获取并更新

127.0.0.1:6379> set next 30
OK
127.0.0.1:6379> get next
"30"
127.0.0.1:6379> getset next 31
"30"
127.0.0.1:6379> get next
"31"

数据库

127.0.0.1:6379> config get databases
1) "databases"
2) "16"
127.0.0.1:6379> info keyspace
# Keyspace
db0:keys=2,expires=0,avg_ttl=0

KEY移动数据库

127.0.0.1:6379> move age 2
(integer) 1
127.0.0.1:6379> keys *
1) "name"
127.0.0.1:6379> select 2
OK
127.0.0.1:6379[2]> keys *
1) "age"
127.0.0.1:6379[2]> info keyspace
# Keyspace
db0:keys=1,expires=0,avg_ttl=0
db2:keys=1,expires=0,avg_ttl=0

Tip:
Redis 使用 DB number 实现类似关系型数据库中 schema 的功能。不同 DB number 表示的数据库是隔离的，但是目前只能使用数字来表示一个数据库

redis-cli -n dbnumber
redis://127.0.0.1:6379/dbnumber

python 调用

[root@MiWiFi-R2100-srv ~]# python -m pip install redis
Collecting redis
Downloading https://files.pythonhosted.org/packages/a7/7c/24fb0511df653cf1a5d938d8f5d19802a88cef255706fdda242ff97e91b7/redis-3.5.3-py2.py3-none-any.whl (72kB)
100% |████████████████████████████████| 81kB 13kB/s
Installing collected packages: redis

[root@MiWiFi-R2100-srv ~]# python
Python 2.7.5 (default, Nov 20 2015, 02:00:19)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.

>>> import redis
>>> client=redis.Redis()
>>> client.get('name')
'weejar zhang'
>>> client.get('age')
'33'
>>> client.get('名字')
'\xe5\xbc\xa0\xe7\xbb\xb4\xe7\x85\xa7'
>>> client.get('名字').decode

>>> print(client.keys())
['keyname', 'name', 'age', '\xe5\x90\x8d\xe5\xad\x97']
>>> for key in client.keys():
... print(key.decode())
...
keyname
name
age
Traceback (most recent call last):
File "", line 2, in
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe5 in position 0: ordinal not in range(128)

>>> import sys
>>> reload(sys)
<module 'sys' (built-in)>
>>> sys.setdefaultencoding('utf8')
>>> for key in client.keys():
... print(key.decode())
...
keyname
name
age
名字

>>> for key in client.keys():
... print(client.get(key))
...
valuename
weejar zhang
33
张维照
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