Redis Reference Guide: From data types to operation instructions

Redis is an open source in-memory key-value storage database. It provides a variety of data types and corresponding operation instructions, and can be used in applications in a variety of scenarios. This article will introduce the data types and operation instructions of Redis.

1. Data type

1.1 String type

The string type is one of the most basic data types in Redis. It is a byte array stored in the form. Values ​​of type string can be any string, including binary data. Redis provides many operation instructions, such as SET, GET, INCR, etc.

1.2 List type

The list type is an ordered collection composed of a sequence of elements. The element can be any string. Redis provides a series of operation instructions to operate lists, such as LPUSH, RPUSH, LPOP, RPOP, LLEN, LINDEX, etc.

1.3 Collection type

A collection type is an unordered collection composed of a set of elements. The element can be any string. The characteristic of the collection type is that the elements are not repeatable. Redis provides a series of operation instructions to operate the collection, such as SADD, SMEMBERS, SPOP, SCARD, SISMEMBER, etc.

1.4 Ordered set type

The ordered set type is an ordered set composed of a set of elements. The element can be any string. Each element has a corresponding score, which can be any floating point number. The characteristic of the ordered set type is that the elements are not repeatable and the elements can be sorted based on scores. Redis provides a series of operation instructions to operate ordered sets, such as ZADD, ZRANGE, ZREMRANGEBYSCORE, ZRANK, ZCOUNT, etc.

1.5 Hash type

The hash type is a data type stored in the form of key-value pairs. The hash type can be understood as a nested dictionary, where each key-value pair is a field. Redis provides a series of operation instructions to operate hash types, such as HMSET, HGETALL, HINCRBY, HDEL, HEXISTS, etc.

2. Operation instructions

2.1 SET and GET

The SET instruction is used to set the value of the key, and the GET instruction is used to obtain the value of the key. For example:

SET key value
GET key

2.2 INCR and DECR

The INCR instruction is used to increase the value of the key, and the DECR instruction is used to decrease the value of the key. For example:

INCR key
DECR key

2.3 LPUSH and RPUSH

The LPUSH instruction is used to add an element to the left side of the list, and the RPUSH instruction is used to add an element to the right side of the list. For example:

LPUSH key value
RPUSH key value

2.4 LPOP and RPOP

The LPOP instruction is used to pop an element from the left side of the list, and the RPOP instruction is used to pop an element from the right side of the list. For example:

LPOP key
RPOP key

2.5 SADD and SMEMBERS

The SADD instruction is used to add an element to the collection, and the SMEMBERS instruction is used to obtain all elements in the collection. For example:

SADD key value
SMEMBERS key

2.6 SPOP and SCARD

The SPOP instruction is used to randomly delete an element in the set, and the SCARD instruction is used to obtain the size of the set. For example:

SPOP key
SCARD key

2.7 ZADD and ZRANGE

The ZADD instruction is used to add an element to an ordered set, and the ZRANGE instruction is used to obtain elements within a specified range in an ordered set. For example:

ZADD key score value
ZRANGE key start stop

2.8 HMSET and HGETALL

The HMSET instruction is used to set multiple fields in the hash type, and the HGETALL instruction is used to obtain all fields and corresponding values ​​in the hash type. For example:

HMSET key field1 value1 field2 value2
HGETALL key

3. Conclusion

This article introduces the data types and operation instructions of Redis, covering the basic usage of Redis. Of course, in actual use, Redis has more advanced features and operating instructions, which require further understanding and learning. We hope this article can help readers better understand and use Redis.

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