Verify if the specified member exists in a key.
验证HASH表中是否存在指定的KEY-VALUE
Parameters
key
memberKey
Return value
BOOL: If the member exists in the hash table, return TRUE, otherwise return FALSE.
Examples
$redis->hSet('h', 'a', 'x');
$redis->hExists('h', 'a'); /* TRUE */
$redis->hExists('h', 'NonExistingKey'); /* FALSE */