Notifications

water-api/sql/add_notifications.sql

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+-- ============================================================================
+-- Add Notifications Table
+-- Migration for notification system supporting negative flow alerts
+-- ============================================================================
+
+-- Create notification type enum
+CREATE TYPE notification_type AS ENUM ('NEGATIVE_FLOW', 'SYSTEM_ALERT', 'MAINTENANCE');
+
+-- ============================================================================
+-- TABLE: notifications
+-- ============================================================================
+CREATE TABLE notifications (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    meter_id UUID REFERENCES meters(id) ON DELETE SET NULL,
+    notification_type notification_type NOT NULL DEFAULT 'NEGATIVE_FLOW',
+    title VARCHAR(255) NOT NULL,
+    message TEXT NOT NULL,
+    meter_serial_number VARCHAR(255),
+    flow_value DECIMAL(12, 4),
+    is_read BOOLEAN NOT NULL DEFAULT FALSE,
+    read_at TIMESTAMP WITH TIME ZONE,
+    created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Indexes for performance
+CREATE INDEX idx_notifications_user_id ON notifications(user_id);
+CREATE INDEX idx_notifications_meter_id ON notifications(meter_id);
+CREATE INDEX idx_notifications_is_read ON notifications(is_read);
+CREATE INDEX idx_notifications_created_at ON notifications(created_at DESC);
+CREATE INDEX idx_notifications_user_unread ON notifications(user_id, is_read) WHERE is_read = FALSE;
+
+COMMENT ON TABLE notifications IS 'User notifications for meter alerts and system events';
+COMMENT ON COLUMN notifications.user_id IS 'User who receives this notification';
+COMMENT ON COLUMN notifications.meter_id IS 'Related meter (nullable if meter is deleted)';
+COMMENT ON COLUMN notifications.notification_type IS 'Type of notification';
+COMMENT ON COLUMN notifications.flow_value IS 'Flow value if negative flow alert';
+COMMENT ON COLUMN notifications.is_read IS 'Whether notification has been read by user';
+COMMENT ON COLUMN notifications.read_at IS 'Timestamp when notification was marked as read';