SQL Server to PostgreSQL Migration Tool

Automated migration tool for converting SQL Server databases to PostgreSQL using hybrid rule-based and AI-assisted conversion. This tool connects directly to SQL Server instances to extract live database schemas, or alternatively works with DACPAC files, then intelligently converts schema and code objects to PostgreSQL-compatible SQL.

📖 For complete workflow, see MIGRATION_WORKFLOW.md

✨ Key Features

🔌 Direct SQL Server Connection: Connects to live SQL Server instances using SMO to extract database schema
📦 DACPAC Support: Alternative extraction from .dacpac or .bacpac files
🤖 Hybrid Migration: Rule-based schema migration (fast, deterministic) + AI-powered code conversion (3-stage pipeline)
📊 Organized Outputs: 10 numbered schema deployment files + individual code objects for version control
⚡ Parallel Processing: Multi-threaded execution for faster migrations
🧩 Extension Detection: Automatically identifies required PostgreSQL extensions (pgcrypto, uuid-ossp, ltree, postgis, etc.)
✅ Production Ready: Proper dependency ordering, UTF-8 encoding, PostgreSQL best practices

📋 Prerequisites

PowerShell 7+ (for automation scripts)
Python 3.8+ (for AI pipeline)
Azure OpenAI access (for code migration) - Get access
SQL Server (for direct extraction) OR .dacpac file
VS Code + GitHub Copilot (optional, for interactive mode)

🚀 Quick Start

1️⃣ Configure Environment

Copy .env.example to .env and configure:

# Azure OpenAI Settings (required for code migration)
DRAFT_AZURE_OPENAI_ENDPOINT=https://your-resource.openai.azure.com
DRAFT_AZURE_OPENAI_KEY=your-key-here
AZURE_OPENAI_DEPLOYMENT_DRAFT=gpt-4o

# SQL Server Connection (for direct extraction)
SQL_INSTANCE=localhost
SQL_SERVER_DATABASE=AdventureWorks2016
SQL_SERVER_USERNAME=sa
SQL_SERVER_PASSWORD=YourPassword
SQL_SERVER_USE_WINDOWS_AUTH=false  # Set to true for Windows Auth

2️⃣ Extract SQL Server Objects

Option A: Direct SQL Server Connection (Recommended)

Connects to a live SQL Server instance and extracts all database objects:

.\scripts\extract_sqlserver_objects.ps1 `
    -Server "localhost" `
    -Database "AdventureWorks2016" `
    -OutputDir "Migrations\AdventureWorks2016\Input\AdventureWorks2016"

Or use credentials from .env:

.\scripts\extract_database.ps1

Option B: From DACPAC File

Extract from a pre-exported .dacpac file:

.\scripts\extract_dacpac_objects.ps1 -Package "path\to\database.dacpac"

⚠️ Important: Let the extraction complete fully. Do NOT run monitoring commands while it's running.

Output Structure:

Migrations/DatabaseName/Input/DatabaseName/
├── Tables/
│   ├── Tables/           # Table definitions
│   ├── Constraints/      # Constraints (PK, FK, Check, Default)
│   └── Indexes/          # Index definitions
└── Programmability/
    ├── Views/            # View definitions
    ├── Functions/        # User-defined functions
    ├── StoredProcedures/ # Stored procedures
    └── Triggers/         # Triggers

3️⃣ Migrate Schema Objects (Automated)

Converts tables, constraints, indexes, sequences using hybrid rule-based + AI approach:

.\scripts\migrate_schema_objects.ps1 `
    -InputDir "Migrations\AdventureWorks2016\Input\AdventureWorks2016" `
    -OutputDir "Migrations\AdventureWorks2016\Output\schema" `
    -MaxParallel 4

Output: 10 numbered deployment files in proper dependency order:

01_extensions.sql - Required PostgreSQL extensions
02_schemas.sql - Schema definitions
03_sequences.sql - Identity sequences
04_tables.sql - Table definitions
05_primary_keys.sql - Primary key constraints
06_unique_constraints.sql - Unique constraints
07_check_constraints.sql - Check constraints
08_default_constraints.sql - Default values
09_foreign_keys.sql - Foreign key relationships
10_indexes.sql - Indexes

4️⃣ Migrate Code Objects (AI-Powered)

Converts views, functions, stored procedures, and triggers using 3-stage AI pipeline:

.\scripts\migrate_code_objects.ps1 `
    -InputDir "Migrations\AdventureWorks2016\Input\AdventureWorks2016" `
    -OutputDir "Migrations\AdventureWorks2016\Output\AdventureWorks2016" `
    -MaxParallel 4

⚠️ Important: Start the command and let it run uninterrupted. Do NOT check progress during execution.

AI Pipeline Stages:

Draft - Initial T-SQL → PostgreSQL conversion
Refine - Improves accuracy by comparing with original
Verify - Validates correctness and syntax

Output:

00_code_extensions.sql - Extensions required by code objects
11_views.sql - All views (consolidated)
12_functions.sql - All functions (consolidated)
13_procedures.sql - All stored procedures (consolidated)
14_triggers.sql - All triggers (consolidated)
Programmability/Views/*.sql - Individual view files for version control
Programmability/Functions/*.sql - Individual function files
Programmability/StoredProcedures/*.sql - Individual procedure files
Programmability/Triggers/*.sql - Individual trigger files

5️⃣ Deploy to PostgreSQL

Deploy the generated files in order:

# 1. Deploy schema (order matters!)
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/01_extensions.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/02_schemas.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/03_sequences.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/04_tables.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/05_primary_keys.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/06_unique_constraints.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/07_check_constraints.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/08_default_constraints.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/09_foreign_keys.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/schema/10_indexes.sql

# 2. Deploy code objects
psql -d your_database -f Migrations/AdventureWorks2016/Output/AdventureWorks2016/Programmability/00_code_extensions.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/AdventureWorks2016/Programmability/11_views.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/AdventureWorks2016/Programmability/12_functions.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/AdventureWorks2016/Programmability/13_procedures.sql
psql -d your_database -f Migrations/AdventureWorks2016/Output/AdventureWorks2016/Programmability/14_triggers.sql

Or use a simple loop:

# Deploy all schema files
for f in Migrations/AdventureWorks2016/Output/schema/*.sql; do
  psql -d your_database -f "$f"
done

# Deploy all code files
for f in Migrations/AdventureWorks2016/Output/AdventureWorks2016/Programmability/*.sql; do
  psql -d your_database -f "$f"
done

6️⃣ Validate (Optional)

Check for any conversion issues:

.\scripts\validate_migrated_objects.ps1 `
    -OutputDir "Migrations\AdventureWorks2016\Output\AdventureWorks2016"

Report saved to: Output/AdventureWorks2016/code_validation.json

🏗️ Architecture

Migration Workflow

SQL Server Instance → Extract → Schema Migration → Code Migration → PostgreSQL
       ↓                 ↓            ↓                  ↓              ↓
  [Live Database]    [Input/]    [01-10.sql]        [11-14.sql]   [Deploy]
   or [DACPAC]

Schema Migration (Hybrid Approach)

90% rule-based for predictable, fast conversion
10% AI assistance for complex edge cases
Handles: data types, constraints, indexes, sequences, user-defined types
Deterministic and repeatable

Code Migration (AI-Powered)

3-stage pipeline (Draft → Refine → Verify)
Uses Azure OpenAI for intelligent conversion
Handles complex T-SQL logic patterns

Intelligent Pattern Handling:

MERGE statements → INSERT ... ON CONFLICT
Cursors → FOR loops or set-based operations
SQL Server functions → PostgreSQL equivalents (GETDATE() → CURRENT_TIMESTAMP)
Window functions → PostgreSQL window function syntax
Temp tables (#temp) → TEMPORARY TABLE
Table variables → CTEs or temp tables
TRY/CATCH → BEGIN ... EXCEPTION

PostgreSQL Extension Detection

Automatically detects and generates extension requirements:

Extension	Purpose	SQL Server Equivalent
`uuid-ossp`	UUID generation	`NEWID()`, `NEWSEQUENTIALID()`
`pgcrypto`	Cryptographic functions	`HASHBYTES()`, encryption functions
`ltree`	Hierarchical data	`hierarchyid`
`postgis`	Spatial types	`geometry`, `geography`
`pg_trgm`	Text similarity	Full-text search functions
`tablefunc`	Crosstab/pivot	`PIVOT`, `UNPIVOT`
`hstore`	Key-value storage	Property bags, JSON

📁 Directory Structure

Migrations/
└── DatabaseName/
    ├── Input/                          # Extracted SQL Server DDL
    │   └── DatabaseName/
    │       ├── Tables/
    │       │   ├── Tables/             # Table definitions
    │       │   ├── Constraints/        # Constraints (PK, FK, etc.)
    │       │   └── Indexes/            # Index definitions
    │       └── Programmability/
    │           ├── Views/              # View definitions
    │           ├── Functions/          # User-defined functions
    │           ├── StoredProcedures/   # Stored procedures
    │           └── Triggers/           # Trigger definitions
    └── Output/
        ├── schema/                     # Schema migration output
        │   ├── 01_extensions.sql
        │   ├── 02_schemas.sql
        │   ├── 03_sequences.sql
        │   ├── 04_tables.sql
        │   ├── 05_primary_keys.sql
        │   ├── 06_unique_constraints.sql
        │   ├── 07_check_constraints.sql
        │   ├── 08_default_constraints.sql
        │   ├── 09_foreign_keys.sql
        │   └── 10_indexes.sql
        └── DatabaseName/               # Code migration output
            └── Programmability/
                ├── 00_code_extensions.sql
                ├── 11_views.sql
                ├── 12_functions.sql
                ├── 13_procedures.sql
                ├── 14_triggers.sql
                ├── Views/              # Individual files
                ├── Functions/          # Individual files
                ├── StoredProcedures/   # Individual files
                └── Triggers/           # Individual files

⚙️ Configuration

Azure OpenAI Setup

Configure different models for each AI stage:

# Draft Stage (initial conversion) - uses GPT-4o
DRAFT_PROVIDER=azure
DRAFT_AZURE_OPENAI_ENDPOINT=https://your-resource.openai.azure.com
DRAFT_AZURE_OPENAI_API_VERSION=2025-01-01-preview
DRAFT_AZURE_OPENAI_KEY=your-key-here
AZURE_OPENAI_DEPLOYMENT_DRAFT=gpt-4o

# Refine Stage (accuracy improvement) - uses GPT-4o
REFINE_PROVIDER=azure
REFINE_AZURE_OPENAI_ENDPOINT=https://your-resource.openai.azure.com
REFINE_AZURE_OPENAI_API_VERSION=2025-01-01-preview
REFINE_AZURE_OPENAI_KEY=your-key-here
AZURE_OPENAI_DEPLOYMENT_REFINE=gpt-4o

# Verify Stage (validation) - can use cheaper model
VERIFY_PROVIDER=azure
VERIFY_AZURE_OPENAI_ENDPOINT=https://your-resource.openai.azure.com
VERIFY_AZURE_OPENAI_API_VERSION=2025-01-01-preview
VERIFY_AZURE_OPENAI_KEY=your-key-here
AZURE_OPENAI_DEPLOYMENT_VERIFY=gpt-4o-mini

Entra ID (Azure AD) Authentication

Leave *_AZURE_OPENAI_KEY blank to use Azure AD authentication:

DRAFT_AZURE_OPENAI_KEY=
# Requires: az login, managed identity, or other DefaultAzureCredential method

SQL Server Connection Options

Windows Authentication:

SQL_INSTANCE=localhost
SQL_SERVER_DATABASE=AdventureWorks2016
SQL_SERVER_USE_WINDOWS_AUTH=true

SQL Server Authentication:

SQL_INSTANCE=localhost
SQL_SERVER_DATABASE=AdventureWorks2016
SQL_SERVER_USERNAME=sa
SQL_SERVER_PASSWORD=YourPassword
SQL_SERVER_USE_WINDOWS_AUTH=false

Connection String (Alternative):

SQL_SERVER_CONNECTION_STRING=Server=localhost;Database=AdventureWorks2016;Integrated Security=True;TrustServerCertificate=True

🎯 Common Scenarios

Scenario 1: Full Database Migration

# 1. Extract from SQL Server
.\scripts\extract_sqlserver_objects.ps1 -Server "localhost" -Database "MyDB"

# 2. Migrate schema
.\scripts\migrate_schema_objects.ps1 -InputDir "Migrations\MyDB\Input\MyDB" -OutputDir "Migrations\MyDB\Output\schema"

# 3. Migrate code
.\scripts\migrate_code_objects.ps1 -InputDir "Migrations\MyDB\Input\MyDB" -OutputDir "Migrations\MyDB\Output\MyDB"

Scenario 2: Schema-Only Migration

.\scripts\extract_sqlserver_objects.ps1 -Server "localhost" -Database "MyDB"
.\scripts\migrate_schema_objects.ps1 -InputDir "Migrations\MyDB\Input\MyDB" -OutputDir "Migrations\MyDB\Output\schema"

Scenario 3: Code-Only Migration

.\scripts\extract_sqlserver_objects.ps1 -Server "localhost" -Database "MyDB"
.\scripts\migrate_code_objects.ps1 -InputDir "Migrations\MyDB\Input\MyDB" -OutputDir "Migrations\MyDB\Output\MyDB"

Scenario 4: Using Stored Credentials

# Configure .env file with connection details
# Then run without parameters:
.\scripts\extract_database.ps1

🔧 Troubleshooting

SQL Server Connection Issues

Problem: "Unable to connect to SQL Server"

Solutions:

Verify SQL Server is running: sqlcmd -S localhost -Q "SELECT @@VERSION"
Check firewall settings (default port 1433)
Ensure SQL Server authentication is enabled (mixed mode)
For Windows Auth, ensure your Windows user has access
Test connection with SSMS first
Check connection string format

Common Error Messages:

Login failed for user 'sa'
→ Check username/password in .env

Named Pipes Provider: Could not open a connection
→ Verify SQL Server service is running

A network-related or instance-specific error
→ Check server name and firewall

Azure OpenAI Errors

Problem: "API key invalid" or "Deployment not found"

Solutions:

Verify endpoint URL in .env (should end with .openai.azure.com)
Check API key is correct and not expired
Ensure deployment name exactly matches your Azure OpenAI resource
Verify API version is supported (2025-01-01-preview recommended)
Check Azure subscription has available quota

Check your configuration:

# Test Azure OpenAI connection
curl -H "api-key: YOUR_KEY" "YOUR_ENDPOINT/openai/deployments/YOUR_DEPLOYMENT/chat/completions?api-version=2025-01-01-preview"

Script Execution Issues

Problem: Script hangs or produces no output

Solutions:

Do NOT monitor progress while script is running
Do NOT check terminal output during execution
Let scripts complete fully before checking results
Check output directory for log files
Increase -MaxParallel parameter if too slow
Decrease -MaxParallel if experiencing API throttling

Migration Quality Issues

Problem: Converted code has errors

Solutions:

Review validation report from validate_migrated_objects.ps1
Check Programmability/ individual files for specific issues
Verify required extensions are installed in PostgreSQL
Test converted SQL in PostgreSQL manually
Check for SQL Server-specific features that need manual conversion

⚠️ Known Limitations

This tool focuses on schema and code migration only. The following are intentionally out of scope:

Feature	Status	Alternative
Data migration	❌ Out of scope	Use `pg_dump`, ETL tools, or custom scripts
CLR assemblies	❌ Not supported	Rewrite in PL/pgSQL or external service
SQL Server Agent jobs	❌ Not supported	Use `pg_cron` extension or external scheduler
Service Broker	❌ Not supported	Use message queues (RabbitMQ, Kafka)
Linked servers	❌ Not supported	Use Foreign Data Wrappers (FDW)
Full-text search	⚠️ Limited	Use PostgreSQL FTS or Elasticsearch
Replication	❌ Not supported	Configure PostgreSQL replication separately
SSRS/SSIS/SSAS	❌ Not supported	Requires separate BI tool migration

🤝 Contributing

Contributions are welcome! To contribute:

Fork the repository
Create a feature branch (git checkout -b feature/amazing-feature)
Make your changes
Test thoroughly
Commit with clear messages (git commit -m 'Add amazing feature')
Push to your branch (git push origin feature/amazing-feature)
Open a Pull Request

Areas for contribution:

Additional SQL Server → PostgreSQL conversion patterns
Support for more data types and functions
Performance improvements
Documentation enhancements
Bug fixes

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

🆘 Support

For issues, questions, or feature requests:

🐛 Bug Reports: Open an issue
💡 Feature Requests: Open an issue
📖 Documentation: See MIGRATION_WORKFLOW.md and MIGRATION_GUIDE.md
💬 Discussions: GitHub Discussions

🙏 Acknowledgments

Built with Azure OpenAI
Uses SQL Server SMO for extraction
Inspired by real-world SQL Server → PostgreSQL migration challenges

Name		Name	Last commit message	Last commit date
Latest commit History 2 Commits
.github		.github
scripts		scripts
.env.example		.env.example
.gitignore		.gitignore
FOLDER_STRUCTURE.md		FOLDER_STRUCTURE.md
MIGRATION_GUIDE.md		MIGRATION_GUIDE.md
MIGRATION_WORKFLOW.md		MIGRATION_WORKFLOW.md
OUTPUT_STRUCTURE.md		OUTPUT_STRUCTURE.md
README.md		README.md

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SQL Server to PostgreSQL Migration Tool

✨ Key Features

📋 Prerequisites

🚀 Quick Start

1️⃣ Configure Environment

2️⃣ Extract SQL Server Objects

3️⃣ Migrate Schema Objects (Automated)

4️⃣ Migrate Code Objects (AI-Powered)

5️⃣ Deploy to PostgreSQL

6️⃣ Validate (Optional)

🏗️ Architecture

Migration Workflow

Schema Migration (Hybrid Approach)

Code Migration (AI-Powered)

PostgreSQL Extension Detection

📁 Directory Structure

⚙️ Configuration

Azure OpenAI Setup

Entra ID (Azure AD) Authentication

SQL Server Connection Options

🎯 Common Scenarios

Scenario 1: Full Database Migration

Scenario 2: Schema-Only Migration

Scenario 3: Code-Only Migration

Scenario 4: Using Stored Credentials

🔧 Troubleshooting

SQL Server Connection Issues

Azure OpenAI Errors

Script Execution Issues

Migration Quality Issues

⚠️ Known Limitations

🤝 Contributing

📝 License

🆘 Support

🙏 Acknowledgments

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