How to read data in redis

Redis provides a variety of data reading methods, including: GET (single key value reading), MGET (batch key value reading), HGET (hash table key value reading), HGETALL (hash table key value reading) Read all key values ​​of the Greek table), LRANGE (read list range data), ZRANGE (read ordered set range members), ZRANGEBYSCORE (read ordered set score range members). The data read by these methods are all in binary format and need to be converted according to the data type. Non-existing keys return nil.

Redis reading data method

Redis is a popular key-value database that provides efficient and convenient Data storage and retrieval capabilities. There are several methods to read data in Redis:

1. GET

The most basic data reading method, used to obtain the value of the specified key. The syntax is as follows:

<code>GET <key></key></code>

2. MGET

Get the values ​​of multiple keys at one time. The syntax is as follows:

<code>MGET <key1> <key2> ... <keyn></keyn></key2></key1></code>

3. HGET

Get the value of the specified key from the hash table. The syntax is as follows:

<code>HGET <hash> <field></field></hash></code>

4. HGETALL

Get all key-value pairs in the hash table. The syntax is as follows:

<code>HGETALL <hash></hash></code>

5. LRANGE

Get the data within the list range. The syntax is as follows:

<code>LRANGE <list> <start> <stop></stop></start></list></code>

6. ZRANGE

Get the members in the specified range in the ordered set. The syntax is as follows:

<code>ZRANGE <zset> <start> <stop></stop></start></zset></code>

7. ZRANGEBYSCORE

Get the members within the specified score range in the ordered set. The syntax is as follows:

<code>ZRANGEBYSCORE <zset> <min> <max></max></min></zset></code>

When reading data, you need to pay attention to the following points:

• Redis stores binary data, so the read data needs to be converted according to the data type .
• If the specified key does not exist, nil will be returned.
• For lists and ordered sets, you can specify a range to read part of the data to improve performance.
• Redis is a double-edged sword. Although it provides extremely high performance, it also requires reasonable design of data structures and use of read and write operations to ensure efficiency.

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