Redis: redis data structure and key operation commands

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Catalog ：

（1）Redis Of 5 Data structures

（2）key Operation command of 1

（3）key Operation command of 2

（4）key Operation command of 3

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（1）Redis Of 5 Data structures

1. String type string

The string type is Redis The most basic data structure in , It can store any kind of data , Including binary numbers

According to the , Serialized data ,JSON The object is even a picture . Maximum 512M.

2. List the type list

Redis List is a simple list of strings , Sort by insertion order , Elements can be repeated . You can add an element to the head of the list （ On the left ） Or tail （ On the right ）, The bottom layer is a linked list structure .

3. Collection types set

Redis Of Set yes string An unordered unrepeated set of types .

4. Hash type hash

         Redis hash It's a string Type of field and value Mapping table ,hash Ideal for storing objects .

5. Ordered set type zset （sorted set）

Redis Ordered set zset And collection set The same is true. string Collection of type elements , And duplicate members are not allowed .

The difference is zset Each element of the is associated with a score （ Scores can be repeated ）,redis Sort the members of the set from small to large by score .

Redis There are a series of commands to operate Redis Data structure of

（2）key Operation command of 1

1.keys

grammar ：keys pattern

effect ： Find all matching patterns pattern Of key.  pattern You can use wildcards .

wildcard ：

1. *： Express 0 Or more characters , for example ：keys * Query all key.
2. ？： Represents a single character , for example ：wo?d , matching word , wood
3. [] ： Express choice [] A character in , for example wo[or]d, matching word, wood, Mismatch wold、woord

 keys * ： Query all key

 keys k * ： General matching , Query all with k At the beginning key

keys h*o ： Query all with h start , With o At the end of the key

 keys h?o : Query all with h start ,o ending , And there is only one character in the middle key

 keys h[abc]llo : Query all with h start , With llo ending , also h You can only go back abc One character in key

 （3）key Operation command of 2

 

 

1.exists

grammar ：exists key[key…]

effect ： Judge key Whether there is

Return value ： Integers , There is key return 1, Other return 0. The use of multiple key, Return to the existing key The number of .

  for example ： return 0 or 1

  Return the number of existence ：

Redis The default is 16 Databases , There is a need to move one data to the second database ：（ With a few ）

2.move

grammar ：move key db

effect ： Move key To the specified database , The mobile key Deleted in original library .

Return value ： Move back successfully 1, Failure to return 0.

hold k Move to 2 Signal library ：

3.ttl

grammar ：ttl key

effect ： see key The remaining lifetime of （ttl: time to live）, In seconds .

Return value ：

1. -1 ： No settings key Survival time , key Never expire .
2. -2：key non-existent

for example ：2 Library No k1, return -2,1 No. library has k1, return -1

 

4.expire

grammar ：expire key seconds

effect ： Set up key Survival time , Over time ,key Automatically delete . The unit is seconds .

Return value ： Set successfully, return number 1, Other things are 0 .

  to k2 Set the existence time ： Set up 20 Delete after seconds  

（3）key Operation command of 3

1.type

grammar ：type key

effect ： see key The data type of the stored value

Return value ： The data type represented by the string

1. none (key non-existent )
2. string ( character string )
3. list ( list )
4. set ( aggregate )
5. zset ( Ordered set )
6. hash ( Hashtable )

  for example ：

2.rename   （key Modification is not recommended ）

grammar ：rename key newkey

effect ： take key Change the name newkey. When key and newkey identical , perhaps key When there is no , Return an error .

When newkey Preexisting time , RENAME The command will override the old value .

  for example ： rename hello：

3.del

grammar ：del key [key…]

effect ： Delete existing key, There is no the key Ignore .

Return value ： Numbers , Delete the key The number of .

for example ： Nonexistent neglect