feature: YearMod shard algorithm

[dk-lockdown]

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implement ShardingAlgorithm interface.

type ShardingAlgorithm interface {
	HasShardingKey(key string) bool
	Shard(condition *KeyCondition) (Condition, error)
	ShardRange(cond1, cond2 *KeyCondition) (Condition, error)
	AllShards() Condition
	AllowFullScan() bool
}

dbpack/pkg/cond/sharding_algorithm.go

Line 239 in 0ae8c77

type YearMod struct {

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[yx9o]

Is it to implement all methods of ShardingAlgorithm?

[dk-lockdown]

Is it to implement all methods of ShardingAlgorithm?

yes

[yx9o]

Can refer to NumberMod?

[dk-lockdown]

Can refer to NumberMod?

yes, very welcome!