Redis Data Type Summary-string

1.1 Data types

There are five data types used by Redis: string, hash, list, set, Zset (sorted set).

Redis internally uses a Redisobject object to represent all keys and value, redisobject the most important information as shown in

The type represents what data type a value object is, and encoding is how different data types are stored inside the Redis, such as: Type=string represents a normal string for value. Then the corresponding encoding can be raw or int, and if it is an int, the actual redis internal is stored and represented by a numeric class, assuming that the string itself can be represented numerically, such as a string such as "123" "456".

Open Redis source scr/sds.h See the structure of string type (note; The following are the source of redis-3.0)

Type is the corresponding 5 data types and is already defined.

1.1.1 String Type

1. 1. String data type

The string is the simplest type, and a key corresponds to a value,string type of data up to 1G. A string type can be treated as an integer, allowing the "INCR" command family to operate (Incrby, DECR, Decrby), in which case the value of the integer is limited to 64-bit signed numbers. The separate element types contained in list, set, and Zset are Redis string types.

1. 2. String data Structure

Open Redis Source Scr/sds.h View the structure of the string type

Len: The length of the tag char[] is somewhat similar to the size of the list in our C #.

Free: The number of unused elements in the tag char[] is the meaning of a few empty pits.

Buf[]: The hole that holds the element is not necessarily equal to the actual number of elements, such as the Cnblogs mentioned earlier. It may also be [c][n][b][l][o][g][s][/0][][][].

1. 3. String data type common commands

Resids related commands can refer to the website information http://doc.redisfans.com/

Redis Data Type Summary-string