PL / SQL继承实现，其中过程在子对象下实现

Question

实体关系图

问题是

鉴于车辆对象模型中描述的继承层次，请为以下问题找到解决方案1.确定适当的对象类型并实现车辆继承类型层次结构2. get_vehicle成员函数返回相应车辆类型的完整信息3. set_gear_count成员过程采用两个参数gear_count和车辆ID，并更新自行车gear_count。4.创建匿名PLSQL块并实例化卡车和自行车实例，然后将它们插入适当的表中。然后演示get_vechile和set_gear_count成员方法的使用。

对于这个问题，我编写了以下PL / SQL，但出现以下错误

SQL> @inheritance;

Warning: Type Body created with compilation errors. 

[当我尝试运行CREATE TYPE BODY bicycle AS主体并且错误的特定区域是set_gear_count过程时，发生错误。

SQL> show error
Errors for TYPE BODY BICYCLE:

LINE/COL ERROR
-------- -----------------------------------------------------------------
10/1     PL/SQL: SQL Statement ignored
10/13    PL/SQL: ORA-00947: not enough values
SQL>

我写的代码如下

--creating the base vehicle object type
CREATE OR REPLACE TYPE vehicle_t AS OBJECT
(
vehicle_id NUMBER,
manufacturer VARCHAR2(30),
purchase_date DATE,
color VARCHAR2 (10),
MEMBER FUNCTION get_vehicle RETURN VARCHAR2
)NOT FINAL;
/

CREATE TYPE BODY vehicle_t AS
MEMBER FUNCTION get_vehicle RETURN VARCHAR2
IS 
BEGIN
RETURN 'Vehicle ID:'|| TO_CHAR (vehicle_id) || 'Manufacturer:'|| manufacturer || 'Purchase Date:'||purchase_date||'Color:'||color;
END get_vehicle;
END;
/

-- CREATING SUB TYPE OF VEHICLE_T POWERED_VEHICLE  
CREATE OR REPLACE TYPE powred_vehicle UNDER vehicle_t
(
fule_type VARCHAR2(30),
license_number VARCHAR2 (10),
model VARCHAR2 (10),
OVERRIDING MEMBER FUNCTION get_vehicle RETURN VARCHAR2
)FINAL;
/

CREATE TYPE BODY powred_vehicle AS
OVERRIDING MEMBER FUNCTION get_vehicle RETURN VARCHAR2
IS 
BEGIN
RETURN (self AS vehicle_t).get_vehicle || 'Fuel Type:'|| fule_type || 'License Number:'||license_number||'Model:'||model;
END get_vehicle;
END;
/

CREATE OR REPLACE TYPE bicycle UNDER vehicle_t
(
gear_count number,
OVERRIDING MEMBER FUNCTION get_vehicle RETURN VARCHAR2,
MEMBER PROCEDURE set_gear_count (p_gear_count IN bicycle, p_vehicleid IN vehicle_t)
)FINAL;
/


CREATE TABLE vehicle_tab OF bicycle;

这是发生错误的地方。

CREATE TYPE BODY bicycle AS
OVERRIDING MEMBER FUNCTION get_vehicle RETURN VARCHAR2
IS 
BEGIN
RETURN (self AS vehicle_t).get_vehicle || 'Gear Count:'|| TO_CHAR(gear_count);
END get_vehicle;
MEMBER PROCEDURE set_gear_count (p_gear_count IN bicycle, p_vehicleid IN vehicle_t)
IS
BEGIN
INSERT INTO vehicle_tab VALUES (p_gear_count, p_vehicleid);
END set_gear_count;
END;
/

Answer 1

我似乎vehicle_tab是一张自行车桌。我认为您想这样做？

INSERT INTO vehicle_tab VALUES (SELF);

而且，我认为p_gear_count是自行车类型令人困惑：它不应该是某种数字吗？