Database migration & conversion
Move, convert or support legacy databases: Oracle to PostgreSQL, Sybase to SQL Server, Informix and Ingres migrations to cloud-ready and open-source databases.
Legacy databases
Four ways to deal with an ageing database
Older databases such as Sybase, Informix, Ingres, DB2 and early versions of Oracle and SQL Server often still run critical systems. As licences rise, support ends and specialist skills disappear, you have four options — and the right one can be different for each system.
Maintain
Keep a stable system running safely: expert support, performance tuning, high availability and workarounds where patches no longer exist.
Move
Upgrade to a supported version or lift it into the cloud — pay monthly for what you use instead of buying and running servers.
Convert
Switch to a modern, cloud-ready or open-source database such as PostgreSQL, MySQL, MariaDB, MongoDB or Azure SQL — cutting licence fees for good.
Retire
Archive the data in an accessible, compliant format and switch the old system off, removing its cost and risk entirely.
Popular routes
Common database migrations and conversions
Each route is delivered by ONQU Support engineers who support both the old and the new database — follow the links for the full guide.
| From | To | Why organisations move | Guide |
|---|---|---|---|
| Oracle Database | PostgreSQL (on-premises or Aurora, Azure, Google Cloud SQL) | Remove per-processor licence and options costs; PL/SQL converted and data validated table by table | Oracle → PostgreSQL |
| SAP Sybase ASE & SQL Anywhere | Microsoft SQL Server or Azure SQL | Shared Transact-SQL heritage makes it the natural move; SQL Server skills are easy to find | Sybase → SQL Server |
| IBM Informix | PostgreSQL | Shrinking skills pool and rising costs; Informix kept supported until you switch | Informix → PostgreSQL |
| Ingres (and ABF / OpenROAD apps) | PostgreSQL, SQL Server or the cloud | Scarce 4GL skills and hard-to-integrate systems; move on your timetable, not after a failure | Ingres migration |
| Older SQL Server versions | Supported SQL Server, Azure SQL or AWS | Avoid running out of security updates and paying for extended support | End-of-support dates |
| Oracle Forms applications | Modern web apps (React / Angular) | Replace end-of-life client tools while keeping the business logic | Oracle Forms conversion |
| Legacy files, spreadsheets, XML, flat files | Relational, NoSQL or cloud databases | Clean, structured, validated data ready for reporting, analytics and AI | Data conversions |
Cloud ready
Where your database can live afterwards
Managed cloud databases
Amazon RDS and Aurora, Azure SQL and Azure Database for PostgreSQL, Google Cloud SQL — backups, patching and scaling handled by the platform.
UK-hosted servers
Your own database server in a UK data centre, managed by ONQU Support — ideal where data must stay in the UK.
Open source, anywhere
PostgreSQL, MySQL, MariaDB, MongoDB and Cassandra run on-premises or in any cloud, with no licence fees and no lock-in.
Low-risk method
How a database migration is delivered
Discovery
Inventory schemas, code, interfaces, data volumes and dependencies — and decide maintain, move, convert or retire for each system.
Proof of concept
Migrate a representative sample first, so you see real results quickly without committing a large budget.
Convert
Translate schema, stored procedures and SQL; update application connections and reports.
Validate
Reconcile data table by table — row counts, checksums and business totals — before anyone relies on it.
Rehearsed cut-over
Practise the switch, then move with minimal downtime and a clear fallback plan.
Support both
The legacy database stays supported until you switch, and the new one is monitored and tuned afterwards.
Database migration FAQ
Should we convert to open source or stay with our current vendor?
If licence and support costs are rising and the application can change, converting to PostgreSQL or MySQL usually pays back quickly. If the database runs a packaged application certified only for one vendor, upgrading and moving to the cloud is often the safer choice.
How long does a database migration take?
A single, well-understood database can move in weeks. Large estates with many interfaces take longer and are best migrated in phases, starting with a proof of concept.
Can we keep the old database running during the move?
Yes. The legacy system stays live and supported until the new one is validated and the cut-over has been rehearsed.
Our database is out of support — is that a problem?
Unsupported databases no longer receive security fixes, which is a risk for compliance and cyber insurance. Check the end-of-support dates and plan a move before you are forced into one.
Hosted and managed for you
Rather not run your own hosting?
ONQU Support is a Fasthosts partner: we set up UK-based hosting for you, move your site across, and look after security, updates, backups and databases — with a named UK team and one simple monthly bill.