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Oracle cross-database data recovery

Oracle cross-database data recovery involves using [[Oracle Database Links]] to retrieve and restore specific data subsets from a remote database instance to a local one.^[600-developer__database__oracle__oracle-db-link.md]

Implementation

To perform this recovery, a [[Database Link]] must first be established on the local (client) machine.^[600-developer__database__oracle__oracle-db-link.md] This link acts as a pointer to the remote database, allowing queries to be executed across the network.^[600-developer__database__oracle__oracle-db-link.md]

The actual data restoration is performed by executing an INSERT INTO ... SELECT statement.^[600-developer__database__oracle__oracle-db-link.md] This statement selects data from the remote table via the link and inserts it into the corresponding local table.^[600-developer__database__oracle__oracle-db-link.md]

Data Logic

The recovery query typically includes conditional logic to ensure data integrity and avoid duplicate entries during the restoration process.^[600-developer__database__oracle__oracle-db-link.md] A common pattern involves selecting records from the remote table (py_order@mypaycenter) that do not already exist in the local table (py_order) based on specific criteria, such as order numbers and date ranges.^[600-developer__database__oracle__oracle-db-link.md]

Sources

  • 600-developer__database__oracle__oracle-db-link.md
  • [[Oracle Database Links]]
  • [[SQL]]