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This article introduces the knowledge of "the analysis of the change of primary key index caused by impdp". Many people will encounter this dilemma in the operation of actual cases, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

When using the data pump to import data, it is sometimes necessary to disable primary key constraints.

Under certain circumstances, there will be the problem of the loss of the primary index and the index change corresponding to the primary key after importing the data.

The official support is as follows.

Disable constraints, delete indexes:

Oracle? Database Administrator's Guide 11g Release 2-"Managing Integrity Constraints"

You can use the ALTER TABLE statement to enable, disable, modify, or drop a constraint. When the database is using a UNIQUE or PRIMARY KEY index to enforce a constraint, and constraints associated with that index are dropped or disabled, the index is dropped, unless you specify otherwise.

A unique key is automatically selected when the constraint is rebuilt:

Why Does The Primary Key Constraint Point To A Different Index After Import? (document ID 1455492.1)

During import, this sequence order is kept. When adding a primary/unique key constraint (step 3), Oracle checks if any existing index can be utilized to enforce the constraint, and in that case, uses it instead of creating a unique index (which was done before in 7.x releases unconditionally). This was done to minimize disk utilization and time needed for the constraint to be enabled.

You can use the keep index option when you disable constraints.

Or delete and rebuild.

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