A developer primarily focuses on designing, implementing, and managing databases and information systems. Their responsibilities include understanding user requirements, creating efficient database structures, writing complex SQL queries, and ensuring data integrity and security. They analyze and optimize database performance, develop data models, and integrate new systems with existing ones. They also manage data backup, recovery, and migration. They collaborate with other software developers to improve system functionality and troubleshoot issues. Additionally, they may be involved in training users on how to interact with the systems, and they stay updated with the latest technology trends.