CRM data model

Entities

• Company: organization identity and basic communication details.
• Contact: person, optionally attached to a company.
• Lead: early demand with stage, owner, value, and next action.
• Opportunity: qualified commercial pipeline with outcome and lost reason.
• FollowUp: dated action linked to relevant CRM records, with creator and optional assignee.
• CrmActivity: append-oriented CRM timeline entry linked to records affected by a mutation.

Companies and contacts are optional on leads and opportunities so incomplete enquiries can be captured without inventing data. Assignment points to active internal users in the UI; foreign keys use SET NULL where history should survive relationship removal. CRM activities cascade with their CRM record while the cross-system ActivityLog remains independent.

Money uses PostgreSQL DECIMAL(14,2). Dates are stored as timestamps. Indexes support stage dashboards, assignment queues, next actions, and due/overdue follow-up queries.