Difference between redis setex and set

SETEX command Redis character string (String) command

SETEX key seconds value

take value Related to key, And will key The lifetime of is set to seconds( In seconds ).
If key Already exist ,SETEX The old value will be overwritten ;

This command is similar to the following two commands ：

$redis->SET('key', 'value');
$redis->EXPIRE('key','seconds');  #  Set the lifetime 

Here's the difference ,SETEX It's an atomicity (atomic) operation , The actions of association value and set lifetime will be completed in the same time , The command is in Redis When used as a cache , Very practical .

Return value ：
When the setting is successful, return OK.
When seconds When the parameter is illegal , Return an error .

#  situation 1：key non-existent 
$redis->SETEX('cache_user_id', 60,100001);//bool(true)
echo $redis->GET('cache_user_id');  #  value  //"100001"

echo $redis->TTL('cache_user_id');  #  Remaining time to live  //int(56)

#  situation 2：key Already exist ,key overwritten 
$redis->SET('cd', "timeless"); //bool(true);
$redis->SETEX('cd', 3000,"goodbye my love"); //bool(true);
echo $redis->GET('cd');//"goodbye my love"