How to Use oracle_cloud_native in PostgreSQL

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How do I connect PostgreSQL to Oracle Cloud Autonomous DB using oracle_cloud_native?

oracle_cloud_native lets PostgreSQL query Oracle Cloud Autonomous DBs via oracle_fdw.

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Description

Example H2

Example H3

What does oracle_cloud_native do?

oracle_cloud_native is a foreign server definition that, when paired with the oracle_fdw extension, allows PostgreSQL to run SQL against Oracle Cloud Autonomous Databases as if the tables were local.

How do I enable the extension?

Run CREATE EXTENSION IF NOT EXISTS oracle_fdw; as a superuser.This installs the FDW required for oracle_cloud_native connections.

What is the basic syntax?

Use CREATE SERVER to register the Oracle Cloud endpoint, then CREATE USER MAPPING for credentials and IMPORT FOREIGN SCHEMA to pull tables.

How do I query ecommerce tables?

After import, you can SELECT, JOIN, and even UPDATE Oracle-hosted Customers, Orders, Products, and OrderItems directly from PostgreSQL.

When should I use it?

Use oracle_cloud_native when your analytics stack is in PostgreSQL but operational data lives in Oracle Cloud, eliminating ETL delays.

Best practices?

Create read-only roles for reporting, push filters down to Oracle with WHERE clauses, and monitor EXPLAIN plans to avoid large data pulls.

Common mistakes and fixes

Mapping the wrong Oracle service name or forgetting to grant USAGE on the server causes connection errors.Verify tnsnames alias and privileges.

Performance tips

Use LIMIT, index relevant Oracle columns, and increase fetch_size option to balance network round-trips.

Why How to Use oracle_cloud_native in PostgreSQL is important

How to Use oracle_cloud_native in PostgreSQL Example Usage


-- Top-selling products last month stored in Oracle Cloud but queried from Postgres
SELECT p.name, SUM(oi.quantity) AS units_sold
FROM orderitems oi
JOIN products p   ON p.id = oi.product_id
JOIN orders   o   ON o.id = oi.order_id
WHERE o.order_date >= date_trunc('month', CURRENT_DATE) - INTERVAL '1 month'
GROUP BY p.name
ORDER BY units_sold DESC
LIMIT 5;

How to Use oracle_cloud_native in PostgreSQL Syntax


CREATE SERVER oracle_cloud_native
    FOREIGN DATA WRAPPER oracle_fdw
    OPTIONS (
        dbserver '//adb.us-phoenix-1.oraclecloud.com:1522/xyz_high'
    );

CREATE USER MAPPING FOR app_user
    SERVER oracle_cloud_native
    OPTIONS (user 'OC_USER', password 'OC_PASS');

IMPORT FOREIGN SCHEMA ecommerce
    FROM SERVER oracle_cloud_native
    INTO public
    OPTIONS (import_default 'yes', import_collate 'yes');

-- Sample query after import
SELECT c.name, o.order_date, o.total_amount
FROM customers c
JOIN orders o ON o.customer_id = c.id
WHERE o.order_date >= CURRENT_DATE - INTERVAL '30 days';

Common Mistakes

Mistake: Omitting the Oracle service name in dbserver string.<br>Why: Connection string resolves to nothing.<br>Fix: Append the service alias like <code>/xyz_high</code> or <code>/xyz_low</code>.
Mistake: Importing all schemas without filters.<br>Why: Pulls thousands of tables, increasing catalog bloat.<br>Fix: Use <code>IMPORT FOREIGN SCHEMA ecommerce LIMIT TO (customers, orders...)</code>.