简述 快速开始 错误处理 SimpleSSDB::__construct auth set setx setnx expire ttl get getset del incr exists getbit setbit bitcount countbit substr strlen keys/rkeys scan rscan multi_set multi_get multi_del hset hget hdel hincr hexists hsize hlist, hrlist hkeys hgetall hscan hrscan hclear multi_hset multi_hget multi_hdel zset zget zdel zincr zexists zsize zlist, zrlist zkeys zscan zrscan zrank, zrrank zrange, zrrange zclear zcount zsum zavg zremrangebyrank zremrangebyscore zpop_front zpop_back multi_zset multi_zget multi_zdel qsize qlist, qrlist qclear qfront qback qget qset qrange qslice qpush qpush_front qpush_back qpop qpop_front qpop_back qtrim_front qtrim_back batch, exec dbsize info