How to Use DB Elephant for Fast MS SQL Database Migration

DB Elephant: Seamless MS SQL to MySQL Conversion Tool

Overview: DB Elephant is a command-line utility that automates migrating databases between different SQL dialects. The focus of this variant is converting Microsoft SQL Server (MS SQL) schemas and data to MySQL-compatible structures and dumps, minimizing manual rewrite of SQL and data-export/import steps.

Key features

• Schema conversion: Translates MS SQL table definitions, indexes, primary/foreign keys, and basic constraints into MySQL-compatible DDL where possible.
• Data export/import: Extracts data from MS SQL and produces MySQL-friendly INSERT statements or CSV exports for bulk loading.
• Type mapping: Maps common MS SQL data types (e.g., DATETIME, NVARCHAR, MONEY) to appropriate MySQL types (e.g., DATETIME, VARCHAR/CHAR, DECIMAL) with sensible defaults.
• Constraint handling: Converts primary keys, unique indexes, and basic foreign keys; flags complex constraints and features (e.g., computed columns, indexed views, CLR types) that require manual attention.
• Stored routines: Attempts to extract stored procedures and functions but typically requires manual rewriting for T-SQL-specific constructs and system functions.
• Character set & collation: Allows specifying target MySQL charset and collation; handles basic Unicode conversions (e.g., NVARCHAR → utf8mb4).
• Dry-run & logging: Offers preview/dry-run mode and detailed logs to review transformed DDL before applying to the target.
• Cross-platform usage: Runs on Windows, Linux, and macOS where supported; often distributed as a binary or via package managers.

Typical workflow

1. Connect to the source MS SQL instance (connection string or credentials).
2. Extract schema and data, optionally filtering databases/tables.
3. Review converted DDL and type mappings in dry-run mode.
4. Apply converted schema to a MySQL test instance.
5. Import data using generated INSERTs or CSV + LOAD DATA INFILE.
6. Manually refactor stored procedures, triggers, and complex constraints as flagged.

Limitations & caveats

• Complex T-SQL features (e.g., TRY/CATCH, MERGE, proprietary system stored procedures) often need manual rewriting.
• Advanced SQL Server types (e.g., hierarchyid, geography, SQL_VARIANT) may not have direct MySQL equivalents.
• Identity/auto-increment semantics and certain index types may require adjustments.
• Transaction semantics and isolation levels can differ between servers; test thoroughly.
• Performance tuning (indexes, query plans) typically needs rework post-migration.

When to use

• Small-to-medium migrations where automated DDL and data conversion saves time.
• Initial lift-and-shift migrations followed by manual tuning.
• As a pre-migration assessment tool to identify incompatible objects.

Alternatives to consider

• Native tools like MySQL Workbench migration wizard.
• Commercial migration services (AWS DMS, Azure Database Migration Service).
• Other open-source converters and ETL tools (e.g., pgloader for PostgreSQL, custom scripts using Python/Go).

Quick tips

• Run conversions in dry-run mode first and inspect logs.
• Convert and test one schema/table at a time for complex databases.
• Preserve backups of source data and scripts before applying changes.
• Recreate users, permissions, and scheduled jobs separately—these often don’t translate.

If you want, I can generate an example command-line conversion run and sample converted DDL for a specific MS SQL table.