简介
PostgreSQL 中的存储过程(Stored Procedure)是一种在数据库中定义的可重复使用的程序单元,用于封装复杂的业务逻辑和数据处理操作
示例
简单示例
- 创建存储过程
CREATE PROCEDURE insert_users (user_account TEXT, hashed_password TEXT) LANGUAGE plpgsql AS $$
BEGININSERT INTO users (user_account, hashed_password)VALUES(user_account, hashed_password);
END $$;
- 调用
CALL insert_users(value1, value2);
事务控制
CREATE PROCEDURE update_salary(emp_id INT, new_salary NUMERIC)
LANGUAGE plpgsql
AS $$
BEGINUPDATE employees SET salary = new_salary WHERE id = emp_id;-- 如果工资小于 0,则回滚事务IF new_salary < 0 THENROLLBACK;ELSECOMMIT;END IF;
END;
$$;
循环
CREATE PROCEDURE insert_multiple_employees()
LANGUAGE plpgsql
AS $$
DECLAREi INT := 1;
BEGINWHILE i <= 5 LOOPINSERT INTO employees (name, salary) VALUES ('Employee_' || i, i * 1000);i := i + 1;END LOOP;
END;
$$;
带输入和输出参数
CREATE PROCEDURE get_employee_salary(IN emp_id INT, OUT emp_salary NUMERIC)
LANGUAGE plpgsql
AS $$
BEGINSELECT salary INTO emp_salary FROM employees WHERE id = emp_id;
END;
$$;
删除存储过程
DROP PROCEDURE xxxxx(TEXT, NUMERIC);