Oracle to PostgreSQL Converter - Free Online Tool 2025

Oracle to PostgreSQL migration is a strategic move for businesses aiming to reduce licensing costs, increase cloud compatibility, and leverage open-source innovation. However, successful migration isn't as simple as copying SQL: Oracle's proprietary syntax, objects, data types, and features often conflict with PostgreSQL's standards. Manual conversion leads to rewrites, compatibility checks, and a high risk of errors.

AI2sql solves these challenges by automatically converting natural-language or Oracle SQL into production-ready PostgreSQL queries—no manual mapping, rewrite, or syntax mastery required. Instantly generate and test optimized PostgreSQL SQL that matches your business logic, accelerating cloud adoption and database modernization.

Oracle to PostgreSQL Migration Overview

Migrating from Oracle to PostgreSQL involves converting schemas, rewriting queries, remapping data types, and reconfiguring app connectivity. Enterprise migrations typically seek cost savings, open-source flexibility, and cloud-readiness. Common migration drivers include:

• Lower TCO (Total Cost of Ownership)

• Vendor independence (escape vendor lock-in)

• PostgreSQL’s advanced features (JSON, window functions, extensions)

• Cloud-native adoption and scaling

Note: Migration projects can impact performance and require careful planning to prevent downtime and data loss. Enterprise-grade solutions like AI2sql platform accelerate safe, reliable transitions.

Key Syntax Differences: Oracle vs PostgreSQL

Direct SQL translation from Oracle to PostgreSQL isn’t possible due to differences in reserved keywords, procedural languages, syntax, and built-in functions. Here’s a syntax comparison:

PL/SQL vs PL/pgSQL

• Oracle uses PL/SQL for procedural logic; PostgreSQL uses PL/pgSQL with different syntax for triggers, functions, and packages

• Some built-in functions and system tables differ or require custom implementation

Data Type Mapping Guide

Accurately mapping data types is crucial for functional and performant data migration. Here’s a quick cross-reference:

Practical Conversion Example

Oracle: CREATE TABLE users (id NUMBER PRIMARY KEY, name VARCHAR2(100), created_at DATE);
PostgreSQL: CREATE TABLE users (id SERIAL PRIMARY KEY, name VARCHAR(100), created_at DATE);

Common Conversion Challenges

• PL/SQL to PL/pgSQL: Procedural code, triggers, and packages may require rewrites

• Sequences & Auto-increment: Oracle’s sequences and triggers vs PostgreSQL SERIAL or IDENTITY columns

• Function and Package Translation: Proprietary Oracle functions may lack direct equivalents; custom conversion needed

• Error Handling: Exception handling syntax changes

• Data Migration: Large objects (LOBs), CLOB/BLOB require careful conversion

• Performance: Query plans, execution methods, and optimizer hints differ

Step-by-Step Migration Process

1. Assessment: Analyze schema, SQL, dependencies, and compatibility

2. Schema Conversion: Convert tables, indexes, constraints

3. Data Type Mapping: Use mapping guide; adjust for precision and scale

4. Procedure & Function Rewrite: Translate PL/SQL to PL/pgSQL

5. Data Migration: Export/import data, validate integrity

6. Application Refactoring: Update application code and connection drivers

7. Testing & Validation: Run both functional and performance tests

8. Go-Live & Monitoring: Plan cut-over and implement monitoring

AI2sql: Generate PostgreSQL Queries from Natural Language

Skip manual conversion – AI2sql instantly generates PostgreSQL SQL from Oracle statements or natural language prompts. No in-depth migration knowledge or error-prone rewrites required. Supports advanced query translation, procedural conversions, and custom mappings for faster enterprise migrations.

Performance Considerations

• Indexing: Revisit index strategy – PostgreSQL’s optimizer behaves differently

• Partitioning: Redesign partitions (syntax and performance characteristics change)

• Bulk Loads: Use PostgreSQL’s COPY command for efficient high-volume imports

• Statistics: Run ANALYZE to refresh planning statistics after import

Schema Migration Best Practices

• Automate schema extraction and conversion

• Validate constraints, foreign keys, and default values

• Address reserved keyword conflicts

• Document naming convention changes

• Test in isolated staging and QA environments

Testing and Validation

• Run data integrity checks

• Validate row/column count and referential integrity

• Compare representative queries and results

• Monitor application performance and error logs closely post-migration

Rollback Strategies

• Retain Oracle backup for immediate rollback if blocking issues arise

• Create repeatable migration scripts

• Implement change control and rollback plans for production cut-over

Conversion Examples: Oracle to PostgreSQL

Troubleshooting: Common Conversion Errors

• Datatype errors: Check precision/scale on NUMERIC types

• Reserved keywords: Enclose conflicting identifiers in quotes or rename

• Function not found: Search PostgreSQL equivalents or use custom implementation

• Constraint/sequence differences: Ensure SERIAL/IDENTITY replace Oracle triggers and sequences

• Date format mismatches: Adjust import/export scripts to match PostgreSQL format (e.g., YYYY-MM-DD)

Optimize PostgreSQL Performance Post-Migration

• Regularly VACUUM ANALYZE to update planner statistics

• Tune work_mem, shared_buffers, and maintenance_work_mem for workloads

• Leverage native Postgres extensions (e.g., pg_partman, PostGIS)

• Monitor queries with EXPLAIN and tune slow statements

Skip Manual Conversion — Generate PostgreSQL Queries Instantly

Accelerate Oracle to PostgreSQL migration by generating ready-to-use SQL using AI2sql: Try AI2sql PostgreSQL Generator.

For further learning, see our PostgreSQL SQL Tutorial and toolkit for Oracle Migration Tools.

Conclusion: Migrate Smarter with AI2sql

Oracle to PostgreSQL migration is a high-stakes but rewarding process, unlocking reduced costs, better scalability, and cloud modernization. Avoid tedious manual rewrites, risk of errors, and project overruns—let AI2sql turn your Oracle SQL or natural language requests into reliable, optimized PostgreSQL queries instantly. Join 50,000+ developers trusting AI2sql for cross-platform, enterprise-grade migrations supporting 15+ database engines. Try AI2sql Free - Generate PostgreSQL Queries from Plain English today.