我正在设计一个对象关系模型数据库。我有一个名为“topico_t”的超类型和这个超类型的 4 个子类型,名为“anotacao_t”、“tarefa_t”、“memo_t”和“contacto_t”。请参阅此处的DDL 片段:
CREATE OR REPLACE TYPE categoria_t AS OBJECT(
nome VARCHAR2(25),
pai REF categoria_t
);
CREATE OR REPLACE TYPE categoria_tab_t AS TABLE OF REF categoria_t;
CREATE OR REPLACE TYPE topico_t AS OBJECT(
titulo VARCHAR2(100),
ultimaAlteracao DATE,
categorias categoria_tab_t
--referencias topico_tab_t
) NOT FINAL;
CREATE OR REPLACE TYPE topico_tab_t AS TABLE OF REF topico_t;
ALTER TYPE topico_t ADD ATTRIBUTE referencias topico_tab_t CASCADE;
CREATE OR REPLACE TYPE periodo_t AS OBJECT(
inicio DATE,
fim DATE
);
CREATE OR REPLACE TYPE repeticao_t AS OBJECT(
frequencia VARCHAR2(10),
duracao periodo_t
);
CREATE OR REPLACE TYPE anotacao_t UNDER topico_t(
periodo periodo_t,
repeticao repeticao_t
);
CREATE OR REPLACE TYPE telefone_t AS OBJECT(
numero VARCHAR2(25)
);
CREATE OR REPLACE TYPE telefone_tab_t AS TABLE OF telefone_t;
CREATE OR REPLACE TYPE morada_t AS OBJECT(
rua VARCHAR2(100),
localidade VARCHAR2(50),
codigoPostal VARCHAR2(10)
);
CREATE OR REPLACE TYPE morada_tab_t AS TABLE OF morada_t;
CREATE OR REPLACE TYPE contacto_t UNDER topico_t(
telefones telefone_tab_t,
moradas morada_tab_t,
email VARCHAR2(100),
url VARCHAR2(150)
);
CREATE OR REPLACE TYPE tarefa_t UNDER topico_t(
dataFim DATE,
completo NUMBER(1,0),
conteudo VARCHAR2(255)
);
CREATE OR REPLACE TYPE memo_t UNDER topico_t(
conteudo VARCHAR2(255)
);
CREATE TABLE categorias OF categoria_t;
CREATE TABLE topicos OF topico_t
NESTED TABLE categorias STORE AS categorias_nested
NESTED TABLE referencias STORE AS referencias_nested;
所以,然后我用这个填充这个表“topicos”:
INSERT INTO topicos VALUES (tarefa_t(
'Dissertacao',
TO_DATE('2018/02/13', 'YYYY/MM/DD'),
categoria_tab_t((select ref(c) from categorias c where nome='FEUP')),
topico_tab_t((select ref(t) from topicos t where titulo='Diogo Pereira'), -- which is an object of the subtype "contacto_t"
(select ref(t) from topicos t where titulo='Comecar a dissertacao'), -- which is an object of the subtype "memo_t"
(select ref(t) from topicos t where titulo='Apresentar Dissertacao'), -- which is an object of the subtype "tarefa_t"
(select ref(t) from topicos t where titulo='Reuniao com Orientador da Dissertacao')), -- which is an object of the subtype "anotacao_t"
TO_DATE('2018/08/13', 'YYYY/MM/DD'),
0,
'Dissertacao all over again'));
因此,我必须构建一个查询,甚至是一个 PL/SQL 块,它返回表“topicos”的所有行,其中至少包含嵌套表“referencias”中提到的这 4 个子类型中的每一个的一个实例对象多于。理想情况下,此查询将返回该行(在上面的INSERT中提到)。
最好的问候,并希望你有一个美好的劳动节!;)