CREATE TABLE "expense_standards" (
    "id" UUID NOT NULL,
    "expense_type_id" UUID NOT NULL,
    "name" VARCHAR(100) NOT NULL,
    "max_amount" DECIMAL(14,2) NOT NULL,
    "per_unit" VARCHAR(20) NOT NULL DEFAULT 'item',
    "control_mode" VARCHAR(16) NOT NULL DEFAULT 'warn',
    "scope_type" VARCHAR(32) NOT NULL DEFAULT 'global',
    "scope_key" UUID,
    "enabled" BOOLEAN NOT NULL DEFAULT true,
    "note" TEXT,
    "created_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "created_by" UUID,
    "updated_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updated_by" UUID,

    CONSTRAINT "expense_standards_pkey" PRIMARY KEY ("id")
);

ALTER TABLE "expense_standards"
ADD CONSTRAINT "expense_standards_expense_type_id_fkey"
FOREIGN KEY ("expense_type_id") REFERENCES "expense_types"("id")
ON DELETE RESTRICT ON UPDATE CASCADE;

CREATE INDEX "idx_expense_standards_enabled_type"
ON "expense_standards"("enabled", "expense_type_id");

CREATE UNIQUE INDEX "expense_standards_type_scope_global_ux"
ON "expense_standards"("expense_type_id", "scope_type")
WHERE "scope_key" IS NULL;

CREATE UNIQUE INDEX "expense_standards_type_scope_scoped_ux"
ON "expense_standards"("expense_type_id", "scope_type", "scope_key")
WHERE "scope_key" IS NOT NULL;