Implement Set data type

[bigboss2063]

Implement the Set data type at the storage engine level.

First, you need to enable the storage engine to support the Set data type.The tasks include designing and adding index for the Set data type, creating Set indexes upon database startup, updating Set indexes after transaction commits, and so on. For the specific implementation, you can refer to the Hash type(This task is already assigned to @yoshihiro-shu, so the next phase of the task may have to wait for him to complete).

Afterward, there are some apis to implement. The specific apis to be implemented are listed in the table below.Please also api test cases for each instruction.

API	Explanation	assigned	done
SADD key member [member ...]	Add one or more members to a set.	@yoshihiro-shu	√
SCARD key	Get the number of members in a set.	@yoshihiro-shu	√
SMEMBERS key	Get all the members in a set.	@yoshihiro-shu	√
SREM key member [member ...]	Remove one or more members from a set.	@yoshihiro-shu	√
SRANDMEMBER key [count]	Get one or more random members from a set.
SPOP key [count]	Remove and return one or more random members from a set.
SMOVE source destination member	Move a member from one set to another.
SDIFF key [key ...]	Get the difference between sets.
SINTER key [key ...]	Get the intersection of sets.
SUNION key [key ...]	Get the union of sets.
SUNIONSTORE destination key [key ...]	Store the union of sets into a new set.

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首先，你需要让存储引擎支持Set数据类型。任务包括为Set数据类型设计和添加索引，在数据库启动时创建Set索引，在事务提交后更新Set索引等。对于具体的实现，你可以参考Hash类型（此任务已经分配给yoshihiro shu，所以下一阶段的任务可能要等他完成）。

然后，接下来还有一些指令需要实现。具体需要实现的指令见下表。每个指令也请完成测试用例的实现。

接口	命令解释	承接人	是否完成
SADD key member [member ...]	向集合中添加一个或多个成员。	@yoshihiro-shu	√
SCARD key	获取集合中的成员数量。	@yoshihiro-shu	√
SMEMBERS key	获取集合中的所有成员。	@yoshihiro-shu	√
SISMEMBER key member	检查成员是否存在于集合中。	@yoshihiro-shu	√
SREM key member [member ...]	从集合中移除一个或多个成员。
SRANDMEMBER key [count]	从集合中随机获取一个或多个成员。
SPOP key [count]	随机移除并返回集合中的一个或多个成员。
SMOVE source destination member	将成员从一个集合移动到另一个集合。
SDIFF key [key ...]	返回给定集合之间的差集。
SINTER key [key ...]	返回给定集合的交集。
SUNION key [key ...]	返回给定集合的并集。
SUNIONSTORE destination key [key ...]	将给定集合的并集存储到一个新的集合中。

[yoshihiro-shu]

HI I’m Yoshi!
I’m in charge of this issue.

[bigboss2063]

@yoshihiro-shu Please go through the list and claim the specific commands you intend to implement.

[yoshihiro-shu]

I intend to implement these command list.

• SADD key member [member ...]
• SCARD key
• SMEMBERS key
• SREM key member [member ...]

[bigboss2063]

Okay, I have assigned these to you.😄

[yoshihiro-shu]

Can I get permission to Make a Pull request?
I think I will finish implement until this weekend.

[bigboss2063]

Can I get permission to Make a Pull request? I think I will finish implement until this weekend.

Of course. You can open pr at any time. I'll help you review.

[bigboss2063]

You should fork your own repository on github, and then open pr in that repository.