mssql2mysql 0.1.1

MSSQL to MySQL migration tool with data, primary key and foreign key support

mssql2mysql

A config-driven CLI tool to migrate Microsoft SQL Server databases to MySQL. Handles data, primary keys, and foreign keys with batch processing and progress tracking.

Features

• Data migration — Copies all tables and rows with configurable batch size
• Schema inference — Builds MySQL tables from MSSQL metadata with automatic type mapping
• Primary keys — Migrates PK constraints from MSSQL to MySQL
• Foreign keys — Migrates FK constraints with strict or smart mode
• Progress tracking — Per-table progress bars and row counts
• YAML config — Single config file for both source and target

Requirements

• Python 3.9+
• SQL Server ODBC Driver (e.g. ODBC Driver 18 for SQL Server)
• MySQL Server (target)

Installation

pip install mssql2mysql

Or from source:

git clone https://github.com/mananpatel08/mssql2mysql.git
cd mssql2mysql
pip install -e .

Quick Start

1. Create a config file

   mssql2mysql --init
   

   This creates migration.yaml in the current directory.

2. Edit the config with your MSSQL and MySQL connection details.

3. Run the migration

   mssql2mysql --config migration.yaml
   

Configuration

Example migration.yaml (from --init):

mssql:
  server: localhost
  port: 1433
  database: your_database
  user: sa
  password: your_password

mysql:
  host: localhost
  database: your_database
  user: root
  password: your_password

mode: strict      # strict | smart
batch_size: 1000

Option	Description
mssql.server	MSSQL host
mssql.port	MSSQL port (default 1433)
mssql.database	Source database name
mssql.user / mssql.password	MSSQL credentials
mysql.host	MySQL host
mysql.database	Target database name
mysql.user / mysql.password	MySQL credentials
mode	strict (default): stop on first FK error. smart: create indexes on referenced columns if needed, continue on FK errors.
batch_size	Rows per insert batch (default 1000)

CLI Reference

Command	Description
mssql2mysql --init	Create a sample migration.yaml in the current directory.
mssql2mysql --config <file>	Run migration using the given YAML config file.

Migration Modes

• strict (default) — Stops the entire migration if any foreign key fails to be added. Use when you want a fully consistent schema.
• smart — Before adding each FK, ensures the referenced column has an index (creates one if missing). On FK add failure, logs the error and continues with the rest. Use when some FKs may be invalid or you prefer best-effort migration.

Type Mapping

MSSQL types are mapped to MySQL as follows (among others):

MSSQL	MySQL
varchar / nvarchar / char / nchar	VARCHAR(n) or LONGTEXT (max)
decimal / numeric	DECIMAL(p,s)
datetime / datetime2	DATETIME
date	DATE
int	INT
bigint	BIGINT
bit	TINYINT(1)
varbinary / binary / image	BLOB / LONGBLOB

Unsupported types fall back to TEXT. Nullability is preserved.

How It Works

1. Data — Connects to MSSQL and MySQL, reads table list and column metadata, creates MySQL tables with mapped types, then batch-inserts rows with progress output. Foreign key checks are disabled during data load.
2. Primary keys — Reads PK definitions from MSSQL INFORMATION_SCHEMA, adds them in MySQL (skips if already present).
3. Foreign keys — Reads FK definitions from MSSQL system tables, adds them in MySQL (in smart mode, creates indexes on referenced columns as needed).

Links

• Repository: github.com/mananpatel08/mssql2mysql
• Issues: github.com/mananpatel08/mssql2mysql/issues

License

MIT © Manan Patel