Siphon

A simple command-line tool for extracting tables from Microsoft SQL Server and loading them into SQLite databases.

The Problem

SQL Server is powerful, but sometimes you need your data somewhere more portable:

• Development & Testing - Spin up a local test environment without needing a full SQL Server instance
• Data Analysis - Share datasets with analysts who use SQLite tools like DB Browser or Datasette
• Offline Access - Take your data on the go without network dependencies
• Cross-Platform Sharing - SQLite runs everywhere - Windows, macOS, Linux, mobile, even in browsers
• Archival - Create portable snapshots of specific tables for long-term storage
• Migration Prep - Extract and inspect data before migrating to other systems

Siphon bridges this gap by making SQL Server-to-SQLite extraction simple and repeatable.

Installation

Prerequisites

• .NET 10 SDK or later
• Access to a SQL Server instance (local or remote)

Build from Source

# Clone the repository
git clone https://github.com/bfowler/siphon.git
cd siphon

# Build the project
dotnet build

# Run the application
siphon --help

Create a Release Build

# Build a self-contained executable for your platform
dotnet publish -c Release -r osx-arm64 --self-contained

# The executable will be in bin/Release/net10.0/osx-arm64/publish/

Available RIDs: win-x64, win-arm64, osx-x64, osx-arm64, linux-x64, linux-arm64

Usage

Command Line Options

Option	Short	Description
--server	-s	SQL Server hostname or instance name
--database	-d	Source database name
--table	-t	Table name(s) to extract (supports wildcards: * and ?)
--output	-o	Output SQLite file path
--username	-u	SQL authentication username (optional)
--password	-p	SQL authentication password (optional)
--windows-auth	-w	Use Windows integrated authentication
--overwrite		Overwrite existing SQLite file
--help	-h	Show help information

Interactive Mode

If you omit required arguments, Siphon will prompt you for them:

siphon
# Prompts for: server, database, table(s), output path
# Prompts for credentials if not using Windows auth

Examples

Extract a Single Table (Windows Authentication)

siphon -s localhost -d MyDatabase -t dbo.Customers -o data.db -w

Extract Multiple Tables

siphon -s localhost -d MyDatabase -t dbo.Customers -t dbo.Orders -t dbo.Products -o data.db -w

Use SQL Server Authentication

siphon -s myserver.example.com -d ProductionDB -t sales.Orders -o orders.db -u myuser -p mypassword

Specify Full Instance Name

siphon -s "MYSERVER\SQLEXPRESS" -d MyDatabase -t dbo.Users -o users.db -w

Overwrite an Existing File

siphon -s localhost -d MyDatabase -t dbo.Logs -o logs.db -w --overwrite

Wildcard Table Selection

Use shell-style wildcards to match multiple tables at once:

Wildcard	Meaning
*	Matches zero or more of any character
?	Matches exactly one of any character

Patterns match against the full schema.table name.

Extract All Tables in a Schema

siphon -s localhost -d MyDatabase -t sales.* -o sales_data.db -w

Extract Multiple Matching Tables

siphon -s localhost -d MyDatabase -t "*.Customer*" -o customers.db -w

Mix Exact Tables and Wildcards

siphon -s localhost -d MyDatabase -t dbo.Users -t sales.* -t reporting.Report* -o data.db -w

Single Character Wildcard

siphon -s localhost -d MyDatabase -t dbo.Table? -o tables.db -w
# Matches: dbo.Table1, dbo.Table2, dbo.TableA, etc.

How It Works

1. Connect - Establishes a connection to your SQL Server instance using Windows or SQL authentication
2. Extract Schema - Reads table structure including columns, data types, and primary keys
3. Type Mapping - Converts SQL Server data types to appropriate SQLite equivalents
4. Create Destination - Creates or updates the SQLite database file
5. Transfer Data - Streams data in batches for efficient memory usage, even with large tables

Type Mapping

SQL Server Type	SQLite Type
bit, tinyint, smallint, int, bigint	INTEGER
decimal, numeric, money, float, real	REAL
char, varchar, nchar, nvarchar, text	TEXT
date, datetime, datetime2, smalldatetime	TEXT (ISO8601)
uniqueidentifier	TEXT
varbinary, binary	BLOB

License

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