PHP Redis::zAdd() Method: Usage and Examples

Adds or updates members of a sorted set with numerical scores.

The objective is to understand the behavior and operational limits, not only the method name.

What It Does

Adds or updates members of a sorted set with numerical scores.

Syntax and Return Value

Redis::zAdd(...)

The return value and exceptional cases depend on the call described here: Equal-score tie ordering is lexicographic, not arrival order; flags may change update semantics.

Requirements: install and enable the corresponding PHP driver or extension and configure the service before running the examples.

Example 1: Basic Use

Requires the phpredis extension and a running Redis server. Keys use a guide-specific prefix; clean up example keys after experimenting.

<?php
$redis = new Redis();
$redis->connect(getenv('REDIS_HOST') ?: '127.0.0.1', (int) (getenv('REDIS_PORT') ?: 6379), 2.0);
$redis->zAdd('guide:zadd:1',3,"taskA",7,"taskB");
echo json_encode($redis->zRange('guide:zadd:1',0,-1,true));

Example 2: A Second Scenario

Requires the phpredis extension and a running Redis server. Keys use a guide-specific prefix; clean up example keys after experimenting.

<?php
$redis = new Redis();
$redis->connect(getenv('REDIS_HOST') ?: '127.0.0.1', (int) (getenv('REDIS_PORT') ?: 6379), 2.0);
$redis->zAdd('guide:zadd:2',4,"taskA",8,"taskB");
echo json_encode($redis->zRange('guide:zadd:2',0,-1,true));

Example 3: Practical Checks

Requires the phpredis extension and a running Redis server. Keys use a guide-specific prefix; clean up example keys after experimenting.

<?php
$redis = new Redis();
$redis->connect(getenv('REDIS_HOST') ?: '127.0.0.1', (int) (getenv('REDIS_PORT') ?: 6379), 2.0);
$redis->zAdd('guide:zadd:3',5,"taskA",9,"taskB");
echo json_encode($redis->zRange('guide:zadd:3',0,-1,true));

Important Behavior and Edge Cases

Equal-score tie ordering is lexicographic, not arrival order; flags may change update semantics.

For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Adds or updates members of a sorted set with numerical scores.
• Equal-score tie ordering is lexicographic, not arrival order; flags may change update semantics.
• sAdd creates an unordered unique set with no scores.

Choose this API or pattern when its exact semantics match your task, and verify the result against the database driver and runtime used by your application.