Add RebuildBatched

[OrkhanAlikhanov]

Original Rebuild was making thousands of individual update queries. I added RebuildBatched which can be
called as:

nestedset.RebuildBatched(db.WithContext(ctx), root, true, 1000)

The method is postgres specific. And can be used by adding following to go.mod file:

replace github.com/longbridgeapp/nested-set => github.com/OrkhanAlikhanov/nested-set v1.5.2

If the model has required fields, it will fail with ERROR: null value in column \"my_column" of relation \"my_table\" violates not-null constraint (SQLSTATE 23502). The workaround is to set default values or make columns nullable which is not great but may worth the change.

[huacnlee]

The method is postgres specific. And can be used by adding following to go.mod file:

Do you means this change only works for Postgres? If true, this is not acceptable, we need to keep support other databases.

[huacnlee]

Or, we need to add a doc here to describe the limitation.

[OrkhanAlikhanov]

Thanks for the quick review.

Do you means this change only works for Postgres? If true, this is not acceptable, we need to keep support other databases.

Technically the library can't be used for mysql or sql server as it uses NULLS FIRST clause ( #22) but I made the PR in case someone wants similar behavior and can use it using go mod replace.

Also, another limitation is that if the table has non-null constraint with no default value, it fails with ERROR: null value in column \"my_column" of relation \"my_table\" violates not-null constraint (SQLSTATE 23502). The workaround is to set default values or make columns nullable which is not great.

[huacnlee]

Yes, I forget that.

[huacnlee]

Thank you