MSSQL to MySQL Database Converter

A comprehensive solution for converting Microsoft SQL Server .bak backup files to MySQL-compatible SQL format.

Overview

This toolkit provides automated scripts to restore MSSQL .bak files and export them as MySQL-compatible SQL files with full schema and data conversion.

Features

• Automatic MSSQL data type to MySQL data type conversion
• Complete schema export with proper MySQL syntax
• Full data export with INSERT statements
• UTF8MB4 encoding support (full Unicode including emojis)
• InnoDB storage engine with transaction support
• Docker-based solution (no MSSQL Server installation required)
• Supports databases of any size
• Automatic logical file name detection

Prerequisites

• Docker Desktop - Required for running MSSQL Server container
• Python 3 - For the Python-based converter (optional)
• Bash - For the shell script converter

Installing Docker

macOS:

brew install --cask docker
# Then start Docker Desktop from Applications

Linux:

# Follow instructions at: https://docs.docker.com/engine/install/

Windows: Download Docker Desktop from docker.com

Quick Start

Using the Bash Script (Recommended)

# Make the script executable
chmod +x convert_mssql_to_mysql.sh

# Run the conversion
./convert_mssql_to_mysql.sh "your-database.bak" output-folder

# Example:
./convert_mssql_to_mysql.sh "Children ES 3.12.2025.bak" sqlOutput

Using the Python Script

# Make the script executable
chmod +x mssql_to_mysql_converter.py

# Run the conversion
python3 mssql_to_mysql_converter.py "your-database.bak" output-folder

# Example:
python3 mssql_to_mysql_converter.py "Children ES 3.12.2025.bak" sqlOutput

How It Works

1. Starts MSSQL Container: Launches a temporary SQL Server 2022 container using Docker
2. Restores Backup: Restores the .bak file inside the container
3. Extracts Schema: Reads all table structures and column definitions
4. Converts Data Types: Maps MSSQL types to MySQL equivalents
5. Exports Data: Generates INSERT statements for all table data
6. Creates SQL File: Outputs a complete MySQL-compatible SQL file
7. Cleanup: Removes the temporary container

Data Type Conversion

The scripts automatically convert MSSQL data types to MySQL equivalents:

MSSQL Type	MySQL Type
int, bigint, smallint, tinyint	INT, BIGINT, SMALLINT, TINYINT
bit	TINYINT(1)
decimal, numeric	DECIMAL(precision,scale)
money	DECIMAL(19,4)
float, real	DOUBLE, FLOAT
datetime, datetime2, smalldatetime	DATETIME
date, time	DATE, TIME
varchar, nvarchar	VARCHAR(length) or TEXT
char, nchar	CHAR(length)
text, ntext	TEXT
binary, varbinary, image	BLOB
uniqueidentifier	CHAR(36)
xml	TEXT

Output Files

After conversion, the output folder contains:

• mysql_schema.sql - Main MySQL database file with schema and data
• filelistonly.txt - Backup file information from MSSQL
• restore.log - Database restoration log
• CONVERSION_SUMMARY.txt - Detailed conversion statistics

Importing to MySQL

Step 1: Create Database

mysql -u root -p -e "CREATE DATABASE your_database CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;"

Step 2: Import SQL File

mysql -u root -p your_database < sqlOutput/mysql_schema.sql

Step 3: Verify Import

# List all tables
mysql -u root -p your_database -e "SHOW TABLES;"

# Check row counts
mysql -u root -p your_database -e "SELECT COUNT(*) FROM TableName;"

Configuration

Adjusting Wait Time

If your database is large, you may need to increase the initialization wait time in the script:

# In convert_mssql_to_mysql.sh, line 71
echo "Waiting for SQL Server to initialize (40 seconds)..."
sleep 40  # Increase this value for larger databases

Custom Database Name

By default, the restored database is named RestoredDB. To change this:

# In convert_mssql_to_mysql.sh, line 50
DB_NAME="YourCustomName"

Troubleshooting

Docker Not Running

Error: Cannot connect to the Docker daemon

Solution: Start Docker Desktop and wait for it to fully initialize

open -a Docker  # macOS
# Wait 30 seconds, then try again

Platform Architecture Warning

Warning: The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8)

Solution: This is normal on Apple Silicon Macs. The script uses --platform linux/amd64 to ensure compatibility.

Restore Failed

Error: Logical file '' is not part of database

Solution: The script automatically detects logical file names. If this fails, check sqlOutput/filelistonly.txt and update the fallback names in the script (lines 105-106).

Connection Timeout

Error: Container starts but sqlcmd commands fail

Solution: Increase the wait time (see Configuration section above)

Example Output

===================================
MSSQL to MySQL Converter
===================================
Input file: Children ES 3.12.2025.bak
Output directory: sqlOutput

✓ Docker is running

Starting MSSQL Server container...
✓ Container started: mssql_converter_12345
Waiting for SQL Server to initialize (40 seconds)...

Reading backup file information...
✓ Detected logical names: Data='ChildrenDB', Log='ChildrenDB_log'

Restoring database...
✓ Database restored successfully

Exporting database schema...
✓ Found 24 tables

Generating MySQL conversion script...
Processing 24 tables...
  Processing: TblPatient...
    Exporting 4449 rows...
  Processing: TblMedTreat...
    Exporting 73808 rows...
  ...

✓ Schema exported to: sqlOutput/mysql_schema.sql

=========================================
✓ Conversion Complete!
=========================================

Performance

• Small databases (< 100MB): ~1-2 minutes
• Medium databases (100MB - 1GB): ~3-10 minutes
• Large databases (> 1GB): Varies based on size and complexity

Limitations

• Primary keys and foreign keys are not automatically preserved (only table structure and data)
• Indexes are not migrated (you may need to recreate them in MySQL)
• Stored procedures, views, and triggers are not converted
• Computed columns are converted to regular columns with their current values

Advanced Usage

Converting Multiple Databases

#!/bin/bash
for bak_file in *.bak; do
    folder_name="${bak_file%.bak}_output"
    ./convert_mssql_to_mysql.sh "$bak_file" "$folder_name"
done

Automated Import

#!/bin/bash
DB_NAME="your_database"
mysql -u root -p -e "DROP DATABASE IF EXISTS $DB_NAME;"
mysql -u root -p -e "CREATE DATABASE $DB_NAME CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;"
mysql -u root -p $DB_NAME < sqlOutput/mysql_schema.sql
echo "Import complete!"

Files Included

• convert_mssql_to_mysql.sh - Main bash conversion script
• mssql_to_mysql_converter.py - Alternative Python script
• README.md - This documentation file

Technical Details

Docker Container Specifications

• Image: mcr.microsoft.com/mssql/server:2022-latest
• Platform: linux/amd64 (for compatibility)
• Port: 1433 (SQL Server default)
• Memory: Uses Docker default (minimum 2GB recommended)

SQL Tools Version

The scripts use sqlcmd from /opt/mssql-tools18/bin/ which includes:

• TLS/SSL support with -C flag
• Unicode support
• Modern authentication methods

License

This project is provided as-is for database migration purposes.

Support

For issues or questions:

1. Check the Troubleshooting section above
2. Verify Docker is running: docker info
3. Check the log files in the output folder
4. Ensure the .bak file is not corrupted

Contributing

Feel free to modify and extend these scripts for your specific needs. Common customizations:

• Add support for indexes and foreign keys
• Implement stored procedure conversion
• Add progress bars for large databases
• Include view and trigger migration

Version History

• v1.0 - Initial release with basic conversion
• v1.1 - Added automatic logical name detection
• v1.2 - Improved data type mapping and UTF8MB4 support
• v1.3 - Added comprehensive error handling and logging

Author

Ahmed Helal Generated for database migration tasks using Docker and SQL Server tools.

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Note: Always test the converted database thoroughly before using it in production. It's recommended to verify data integrity and recreate any necessary indexes, foreign keys, and constraints after import.