55 行
1.2 KiB
PL/PgSQL
55 行
1.2 KiB
PL/PgSQL
CREATE SEQUENCE "employee_number_seq"
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START WITH 1
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INCREMENT BY 1
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NO MINVALUE
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NO MAXVALUE
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CACHE 1;
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DO $$
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DECLARE
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v_next_value INTEGER;
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BEGIN
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SELECT COALESCE(MAX(SUBSTRING(employee_no FROM 4)::INTEGER), 0) + 1
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INTO v_next_value
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FROM employees
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WHERE employee_no ~ '^HYD[0-9]{6}$';
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EXECUTE format('ALTER SEQUENCE "employee_number_seq" RESTART WITH %s', v_next_value);
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END;
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$$;
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CREATE OR REPLACE FUNCTION generate_employee_number()
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RETURNS TEXT
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LANGUAGE plpgsql
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AS $$
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DECLARE
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v_seq INTEGER;
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BEGIN
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v_seq := nextval('"employee_number_seq"');
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IF v_seq > 999999 THEN
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RAISE EXCEPTION '员工编号序列已达上限 999999';
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END IF;
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RETURN 'HYD' || LPAD(v_seq::TEXT, 6, '0');
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END;
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$$;
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ALTER TABLE "employees"
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ALTER COLUMN "employee_no" SET DEFAULT generate_employee_number();
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CREATE OR REPLACE FUNCTION prevent_employee_no_update()
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RETURNS trigger
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LANGUAGE plpgsql
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AS $$
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BEGIN
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IF OLD.employee_no IS DISTINCT FROM NEW.employee_no THEN
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RAISE EXCEPTION '禁止修改员工编号：employee_no 是不可变字段';
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END IF;
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RETURN NEW;
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END;
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$$;
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CREATE TRIGGER prevent_employee_no_update_trigger
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BEFORE UPDATE ON "employees"
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FOR EACH ROW
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EXECUTE FUNCTION prevent_employee_no_update();
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