Export Oracle Database to PostgreSQL

Overview of Methods

Exporting data from Oracle to PostgreSQL can be achieved through various methods. Three popular methods are Ora2Pg, Oracle Foreign Data Wrappers (Oracle_fdw), and EnterpriseDB's Migration Tool. Each method has its unique advantages and is suitable for different migration requirements.

Ora2Pg Method

Ora2Pg is a robust tool used to migrate Oracle database objects to PostgreSQL. It supports exporting the entire database schema, tables, functions, triggers, procedures, packages, and BLOB objects. Ora2Pg is an ideal choice for comprehensive Oracle to PostgreSQL migrations.

Oracle Foreign Data Wrappers

Oracle_fdw is an extension that allows PostgreSQL to interact with Oracle databases. It enables PostgreSQL to perform DML operations like SELECT, INSERT, UPDATE, and DELETE directly on Oracle servers. This method is suitable for integrating Oracle data into PostgreSQL workflows.

EnterpriseDB Migration Tool

The EDB Free Oracle to PostgreSQL Migration Tool simplifies the import process from Oracle to EDB PostgreSQL Advanced Server. It ensures compatibility with Oracle features, making it a preferred choice for users seeking a smooth transition to EDB PostgreSQL.

Assessment and Compatibility

Before beginning the migration, assess the Oracle application to estimate the complexity of the process. Compatibility checks are crucial to identify potential challenges due to differences in schemas, data types, and database features between Oracle and PostgreSQL.

Schema Conversion Tools

Utilize schema conversion tools like Ora2pg, Ora_migrator, orafce, and EDB Migration Portal to automate the conversion of Oracle objects to PostgreSQL format. These tools help in adjusting to PostgreSQL's handling of schemas, data types, and lack of certain Oracle features.

Data Migration Approaches

Data migration can be approached in three ways: snapshot, snapshot in parallel, and change data capture (CDC). Choose the method that best fits your downtime tolerance and data synchronization needs. CDC is ideal for continuous data movement with minimal downtime.

Functional and Performance Testing

After schema conversion, conduct functional testing to ensure the application behaves as expected. Follow with performance testing to verify that the PostgreSQL database meets the performance requirements. Only then proceed to migrate the data.

Finalizing the Migration

Complete the data migration using the selected approach, ensuring that all Oracle data is accurately transferred to PostgreSQL. After migration, perform a thorough review and testing to confirm the success of the export process.

Frequently Asked Questions

What are the benefits of migrating from Oracle to PostgreSQL?

Benefits include PostgreSQL being free to install and use, having open-source licensing, availability from public cloud providers, supporting many extensions and more application programming languages, built-in support for unicode and globalization, better support for localizing applications, and a more scalable read cluster. Additionally, PostgreSQL is less expensive than Oracle.

What are the key differences to consider during Oracle to PostgreSQL migration?

Key differences include schema elements like columns, constraints, identifiers, indexes, partitions, tables, tablespaces, and data types. PostgreSQL uses WITH RECURSIVE for hierarchical queries, JOIN instead of (+) for outer joins, and does not have packages, synonyms, TO_DATE function, or a Dual table. CTID in Postgres is similar to ROWID in Oracle.

What tools can facilitate the migration from Oracle to PostgreSQL?

Tools that can help include schema migration tools like Ora2pg, Ora_migrator, and Orafce. EDB Postgres Advanced Server can retain some Oracle functionality due to its compatibility with Oracle and native PL/SQL support, which is useful for migration.

What are some best practices for migrating from Oracle to PostgreSQL?

Best practices involve planning the migration process carefully, using tools to automate schema conversion, verifying application compatibility with Postgres, converting virtual columns to views, being aware of Oracle and Postgres differences, performing functional and performance testing, loading sample data and testing converted objects with DMLs, and using data migration tools for moving data.

How does PostgreSQL handle hierarchical queries and outer joins differently from Oracle?

PostgreSQL uses WITH RECURSIVE for hierarchical queries instead of Oracle's START WITH ... CONNECT BY syntax, and it uses standard SQL JOIN syntax instead of Oracle's (+) operator for left and right outer joins.

Common Use Cases

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  Migrating legacy systems from Oracle to PostgreSQL for cost savings and open-source benefits
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  Consolidating disparate databases into a single PostgreSQL environment for improved data management
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  Enabling cross-database compatibility and interoperability between Oracle and PostgreSQL systems
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  Facilitating data analysis and reporting by exporting Oracle data into PostgreSQL for advanced analytics tools
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  Ensuring business continuity by creating a backup of Oracle database in PostgreSQL format

Sourcetable: A Streamlined Alternative to Oracle-to-PostgreSQL Exports

Seamless Data Integration: Sourcetable provides a unified platform for aggregating data from various sources, including Oracle databases, eliminating the complexity of traditional database export processes.

Real-Time Data Access: Unlike the static nature of exports, Sourcetable enables real-time querying of Oracle data within a familiar spreadsheet interface, offering up-to-the-minute insights without the typical export wait times.

Spreadsheet Simplicity: Transitioning data from Oracle to PostgreSQL can be technical and time-consuming. Sourcetable simplifies this by allowing users to manipulate and analyze data using intuitive spreadsheet operations, bypassing the steep learning curve associated with database management.

Dynamic Data Manipulation: Sourcetable empowers users to perform on-the-fly data analysis and manipulation directly within its interface, providing a flexible alternative to the rigid structure of database exports and imports.