Posts with the same common tags

While using the below structure:

type Post {
  tags: [Hashtag!]
type Hashtag {
  value: String!

If 2 or more posts have the same common tags, like #winter, will HashTag Table store only unique tags?

When I create a post with the same tags, the tags are saved again in HashTag table with different hypi id.

Use the tag.value as the so when you save a tag, set = ‘tag value’ AND = ‘tag value’ - by setting you guarantee not to create new tags. You could also use the hash of the tag as the ID.