Design and develop database solutions including schemas, tables/collections, indexes, constraints, and data access patterns aligned to application requirements and performance SLAs. Build and maintain SQL and PL/SQL components (queries, views, stored procedures, functions, packages, triggers) and support batch/transactional workloads. Design MongoDB collections and implement efficient query patterns (including aggregation pipelines), indexing strategy, and schema evolution approaches. Perform performance tuning and troubleshooting across platforms (execution plan analysis, indexing/partitioning strategies, query optimization, and workload profiling). Implement data quality checks, reconciliation routines, and controls to ensure accuracy, integrity, and auditability of data. Collaborate with engineering teams on API/data contract design, transaction management, and integration patterns (batch, near-real-time, and service-based). Support production operations: monitoring/alerting, incident response, root cause analysis, and preventive remediation; contribute to runbooks and operational documentation. Follow engineering discipline: code reviews, version control, testing practices, and change/release management