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If your entity uses a sequence ID, you will get new IDs when you import the data into production because the sequence you use in development will likely be at a different value than the sequence in production. (v5.1 and previous version behaves this way – v5.2 will changeoffers new features to make this task easier).
The instability of the IDs because of the inconsistency of the next value in the development vs. production sequence means you must factor in the references/relationship IDs. Respect the sequence values to avoid sequence conflicts. Manually increment the sequence to a bigger number in Production (this means make sure the next value for the sequence in Production is set to a larger number than the range of ID values you are using in the dev data you’re about to import).
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