Redis Database Learning

Redis Overview

Redis is an open-source, Advanced Key-value store. It is commonly referred to as a data structure server because keys can contain strings, hashes, linked lists, collections and an ordered set of Redis briefs        Redis is completely open source free, complies with BSD protocol and is a high performance Key-value database. Redis and other Key-value cache products have the following three features: Redis support data persistence, you can save in-memory data on disk, restart can be loaded again for use. Redis not only supports simple key-value types of data, but also provides storage of data structures such as List,set,zset,hash. Redis supports backup of data, that is, Master-slave mode of data backup. (Master-slave)   Redis Advantage        performance is very high –redis can read the speed is 110,000 times/s, the write speed is 81,000 times/s. Rich data types –redis support for binary case Strings, Lists, hashes, sets and Ordered sets all operations of atomic –redis are atomic, and Redis supports atomic execution of several operations. Rich features –redis also supports publish/subscribe, notifications, key expiration, and more. What is the difference between Redis and other Key-value storage?       Redis has more complex data structures and provides atomic manipulation of them, which is a different evolutionary path from other databases. The data types of Redis are based on basic data structures and are transparent to programmers without the need for additional abstraction. Redis runs in memory but can be persisted to disk, so it is necessary to weigh the memory when writing to different datasets at high speed because the amount of data cannot be larger than the hardware memory. Another advantage of the in-memory database is that it is very simple to operate in memory compared to the same complex data structure on disk, so Redis can do a lot of things that are internally complex. At the same time, they are compact in the form of disks, because they do not have to be randomly accessed.     

Redis Installation

Redis installation is divided into Linux under the installation and win under the installation, network tutorials More, here non-emphasis omitted!

Redis data types

Redis supports five types of data:    string (String)    list (list)    set (collection) (unordered collection)    Zset (ordered collection)    hash (hash)

String (String)

The string is the most basic type of redis, and you can understand it as a type that is identical to memcached, a key that corresponds to a value. The string type is binary safe. This means that a Redis string can contain any data. For example, JPG images or serialized objects. The string type is the most basic data type of Redis, and a key can store up to 512MB.

String operation:

1.set  Key value     //Set a key and value that does not exist create, overwrite, return ok2.get  key     //Get value of a key, return result 3.setnx  key  value      //Set a non-existent key and value 4.setex key  seconds  value   //Set a key value with expiration date 5.ttl  key    //view key for valid time 6.setrange  key   Position    value    //replacement string  EX:  setrange  name  4  strs    // Replace the name key with the fourth position. Strs7.mset  key1 value1  key2 value2  key3 value3    //Batch Set key value 8.msetnx     // Bulk set non-existent key value pair 9.getset    //Get original value replaced with other value    EX:   getset   key   new_value10.getrange     //Gets the value of the specified range    EX:  getrange  key   0   411.mget    //Batch Get value 12.INCR     //Gagacao as 13.incrby  key   2     //Set a key value plus a certain number (both positive and negative) 14.DECR  //minus minus operation 15.decrby   key   2    //Set a key value minus a number 16.append   key   app_value//       append value to specified key 17.strlen   key     //Length of key

List (lists)

The Redis list is a simple list of strings, sorted by insertion order. You can add an element to the head of the list (to the left) or to the tail (to the right).

List operations

1. Lpush  list1  ' Hello '    //in List1 head Insert a string 2.rpush  list1  ' world '/    /Insert a string at List1 tail 3.lrange  list1 0-1    //Get all content in List1 4.linsert  list1  "Before/after" Old_value new_value      // Insert a new value before or after the old value 5.lset  list1  0  ' hello '    //Modify the value at the specified position 6.lrem  list1  2  ' Hello '     //Delete the first two Hello values 7.lrem  list1  -2  ' hello '   //delete after two hello values 8.lrem  list1  0  ' Hello '    //delete all Hello values 9.ltrim  list1  1  3    //Delete values outside the specified range 10.lpop  list1      // Removes the element from the List1 's head and returns 11.rpop List1//   removes the element from the tail of List1 and returns 12.lindex  list1   1      // Returns the element at index position in List1 13.llen    list1       //Returns the length on the List1

Unordered collection (set)

Redis's set is an unordered collection of type string. The collection is implemented by a hash table, so the complexity of adding, deleting, and finding is O (1). The Sadd command adds a string element to the set set of key corresponding to successfully returning 1 if the element has returned in the collection 0,key the corresponding set does not have a return error. Sadd Key Member

Unordered collection Operations

1.sadd  key   value       sadd   myset   ' Hello '     //To collection no set adds a data 2.smembers   myset      // Get all elements in MySet 3.srem  myset    ' one '    //delete elements in MySet one4.spop   myset      // Randomly deletes an element in the collection and returns 5.srandmember  myset    //Random return value in MySet without deleting 6.smove  myset1  myset2   Lala     Move lala in Myset1 to Myset2 7.scard  myset1     //return myset1 worth 8.sismember  myset lala    // Determine if Lala is in MySet 9.sdiff   myset1   myset2    //Returns the difference set in two sets 10.sdiffstore   newset  Myset1 Myset2   //Save the difference set of two sets to Newset 11.sinter   myset1  myset2   //return intersection of two sets 12.sinterstore   Newset    myset1   myset213.sunion  myset1   myset2    //return set of two sets 14.sunionstore   newset   Myset1  Myset2

Ordered set (Zset)

Ordered collection operations

1.zadd  zset  1 One   //Add one to Zset, sort the weights Score2.zrem  zset One    /remove elements from Zset One3.zincrby   Zset   2 One  //if present One,score plus 2, not present add as 24.zrank Zset one  //return one in Zset ranking (small to large) 5.zrevrank  Zset  One   //return one in Zset ranking (from big to small) 6.zrangebyscore  zset  2 3 withscores  // Returns the element in the set score at a given interval (closed interval) 7.zcount  zset  2  3     //Returns the specified interval worth the number 8.zcard   zset   // Returns the number of elements in the collection 9.zremrangebyrank   zset  3  3    //delete the element in the collection in the specified interval 10.zremrangebyscore   zset  1  2   //Remove elements from small to large score in the collection between

Hash (hashed)

A Redis hash is a collection of key-value pairs. Redis Hash is a string-type field and value mapping table, and hash is particularly useful for storing objects.

Hash operation

1.hset  hashname key value   //Set a hash table of key values 2.hsetnx   hashname key value   // Set a hash table that does not exist in the key and the value 3.hmset   hashname  key1  value1  key2  value2   ... Batch setup 4.hmget   hashnane   key1  key2    ... Bulk get 5.hexists   hashname  key    //Detect if key is present 6.hlen   hashname    //Get the number of keys in the hash table 7.hdel  Hashname  key    //delete hash table in Key8.hkeys  hashname     //return hash table for all keys 9.hvals   hashname    // Returns all values in the hash table 10.hgetall  hashname    //Returns all keys and values

Redis Advanced Applications

1. Security Requirepass Password

2. Persistent AppendOnly Yes

Modifying a configuration file vim/etc/redis/redis.conf

　

Redis Database Learning