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It depends on the situation. If your historical record is for data analysis, for example, if you want to use MapReduce, it is recommended to embed it. If you don’t need to do analysis, it’s fine!
If you add that entity A has a historical record called B, you should add a B table and store A's id.
Generally, there are multiple historical records. It is recommended to save references and separate structures to reduce coupling
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It depends on the situation. If your historical record is for data analysis, for example, if you want to use MapReduce, it is recommended to embed it. If you don’t need to do analysis, it’s fine!
If you add that entity A has a historical record called B, you should add a B table and store A's id.
Generally, there are multiple historical records. It is recommended to save references and separate structures to reduce coupling