Use of the Oracle exp/imp Export Import Tool-2

Three. Issues that may arise with the Import tool imp

(1) Database object already exists

In general, you should completely delete the table, sequence, function/process, trigger, etc. of the target data before importing the data.

The database object already exists, and the import fails by the default imp parameter

If the parameter ignore=y is used, the data contents inside the exp file are imported

If the table has constraints for unique keywords, the condition will not be imported

If the table does not have a constraint on a unique keyword, it causes the record to repeat

(2) The database object has a primary foreign KEY constraint

Data import fails when the primary foreign key constraint is not met

Workaround: Import the primary table first, and then import the dependent tables

Disable the primary foreign key constraints of the target import object, after importing the data, enable them

(3) Insufficient authority

If you want to import a user's data into a B user, a user needs to have Imp_full_database permissions

(4) Storage allocation failure when importing large tables (greater than 80M)

The default exp, compress = Y, is to compress all the data on a block of data.

On import, if there is no contiguous large block of data, the import fails.

When exporting large tables larger than 80M, remember that compress= N does not cause this error.

(5) Different character sets used by IMP and EXP

If the character set is different, the import will fail, you can change the UNIX environment variables or NT registry Nls_lang related information.

After the import is complete, change back.

(6) IMP and EXP versions are not compatible

The IMP can successfully import the files generated by the lower version of exp and cannot import the files that are generated by the high version exp.

Use of the Oracle exp/imp Export Import Tool-2