-- ============================================================
-- P1.8: tree_evaluation 单株评价 —— 试验研究点/座果率负载（规格 §4）
-- ------------------------------------------------------------
-- 幂等。bre_tree_evaluation 表已由 bre_tables.sql 建好。
-- ============================================================

ALTER TABLE bre_tree_evaluation ADD COLUMN IF NOT EXISTS trial_study_id integer REFERENCES bre_trial_study(id);
CREATE INDEX IF NOT EXISTS ix_bre_tree_evaluation_trial_study_id ON bre_tree_evaluation(trial_study_id);

ALTER TABLE bre_tree_evaluation ADD COLUMN IF NOT EXISTS crop_load double precision;