Manage Source Layouts and Changes

Map Partitioned File Layouts

Use a partitioned external-table definition when stable path segments represent logical partition values:

/orders/year=2026/month=07/day=01/part-0001.parquet
/orders/year=2026/month=07/day=02/part-0001.parquet

Depending on the API and deployment, represent the layout as explicit external-table partitions or as path-derived partition columns through documented DBMS_CLOUD format options. Keep the Oracle partition metadata aligned with the physical layout. Oracle does not verify that rows inside an external file satisfy the partition boundary assigned to that file.

When explicit partition metadata is used and source partitions change, use the documented synchronization operation such as DBMS_CLOUD.SYNC_EXTERNAL_PART_TABLE for that partition-discovery model. Hidden FILE$PATH and FILE$NAME columns can support lineage and diagnostics where the access path exposes them.

For an explicit partitioned external table created with DBMS_CLOUD.CREATE_EXTERNAL_PART_TABLE, synchronize added or removed source partitions as follows:

BEGIN
  DBMS_CLOUD.SYNC_EXTERNAL_PART_TABLE(
    table_name => 'ORDERS_EXT');
END;
/

Note - Explicit partitions only. Do not run this synchronization for implicit partitioning, where partition values are derived from paths and new objects are discovered without an explicit partition-sync step.

This section defines the mapping. Partition pruning, folder design, file count, and statistics are covered in Chapter 6.

For DBMS_CLOUD partition-management procedures, see DBMS_CLOUD.
For an Autonomous AI Database path-derived partitioning example, see Query External Tables with Implicit Partitioning.

Handle Source Changes

Access path	Response to a source change
Persistent external table	Alter or recreate the definition when locations, columns, data types, parsing rules, or explicit partitions change.
Inline external table	Update the definition in the SQL statement.
Mounted catalog table	Update the authoritative external catalog and use the provider-supported metadata refresh when the database has cached older metadata.

Do not place files with incompatible schemas under one wildcard location and expect Oracle to reconcile them. Version breaking source schemas or provide a compatibility view.

Related documentation: