Data Migration

WhoDB helps you inspect source and destination databases, run validation SQL, and export small or moderate datasets.

Migration Workflow

1. Connect to the source database.
2. Use Storage Units and Describe to inspect objects.
3. Use Data and WHERE conditions to sample rows.
4. Use Scratchpad for row counts, quality checks, and post-migration validation.
5. Use native database tools for large exports/imports.
6. Reconnect to the destination database and validate.

Inspect Source Structure

Open Storage Units and click Describe on important objects.

Use Describe for structure and Data for rows.

Run Pre-Migration Checks

Open Scratchpad and run source validation queries.

SELECT COUNT(*) AS total_users
FROM users;

SELECT email, COUNT(*) AS duplicates
FROM users
GROUP BY email
HAVING COUNT(*) > 1;

SELECT COUNT(*) AS missing_email
FROM users
WHERE email IS NULL OR email = '';

Export From WhoDB

Use WhoDB export for grid-sized workflows.

Current CE formats are:

• CSV.
• Excel .xlsx.
• JSON Lines for records from sources like MongoDB when supported.

For SQL dumps and large migrations, use native database tools.

For large migrations, prefer native tools:

• PostgreSQL: pg_dump, pg_restore, COPY.
• MySQL/MariaDB: mysqldump, mysql, LOAD DATA.
• SQLite: .backup, .dump.
• MongoDB: mongodump, mongorestore.

Validate Destination

After importing into the destination, connect WhoDB to the destination database and run comparable checks:

SELECT COUNT(*) AS total_users
FROM users;

SELECT COUNT(*) AS orphan_payments
FROM payments p
LEFT JOIN users u ON u.id = p.user_id
WHERE u.id IS NULL;

SELECT *
FROM users
ORDER BY id
LIMIT 20;

Document source and destination row counts, orphan checks, duplicate checks, and any known transformations.

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