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Redis HSET in PHP (Detailed Guide w/ Code Examples)

Use Case(s)

The HSET command in Redis is used to set the value of a field in a hash stored at a key. A common use case for this is storing object-like data, where each object has a unique ID and various attributes. For instance, you could store details about a user, with fields like username, email, and password.

Code Examples

Let's look at an example using the PHP Redis extension. First, we need to establish a connection to the Redis server:

$redis = new Redis(); $redis->connect('127.0.0.1', 6379);

Then, we can use the hSet method to set a field in a hash:

$redis->hSet('user:1', 'name', 'John Doe');

In this example, 'user:1' is the key of the hash, 'name' is the field, and 'John Doe' is the value that we're setting for that field.

We can also set multiple fields at once:

$redis->hMSet('user:1', array( 'email' => 'johndoe@example.com', 'password' => 'secret' ));

Best Practices

  • Always check the return value of the hSet function. It returns 1 if the field is a new field in the hash and the value was set. If the field already exists, and the value was updated, it returns 0.
  • For complex applications, consider namespacing your keys with a colon (:) to avoid potential collisions.

Common Mistakes

  • One mistake is not handling the possibility of a connection failure. Always ensure that the Redis server is available and that the connection is successful before trying to set values.
  • Another mistake is forgetting that field names are case sensitive. 'Name' and 'name' would be considered different fields.

FAQs

Q: Can I use hSet to update multiple fields at once? A: Yes, you can use the hMSet function to set multiple fields at once.

Q: What data types can I store with hSet? A: You can store strings, integers, and floating point numbers. Note that they will all be stored as strings and converted back when retrieved.

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Dragonfly is fully compatible with the Redis ecosystem and requires no code changes to implement.