Oracle SQL在嵌套表中创建标识列

Question

我正在制作一个包含嵌套表的表：

create DOCUMENT as OBJECT (
DOC_ID NUMBER,
DESCRIPTION VARCHAR(1000));   
create type documents_t is table of DOCUMENT;
create table projects (
ID NUMBER GENERATED ALWAYS AS IDENTITY ,
DOCUMENTS documents_t)
NESTED TABLE DOCUMENTS STORE AS documents_nested(
(PRIMARY KEY(nested_table_id, DOC_ID)) ORGANIZATION INDEX);

这还可以，但我似乎找不到如何将嵌套表的主键作为标识列。有什么建议吗？感谢

Answer 1

请找到代码片段，

CREATE SEQUENCE seq_documents
START WITH     1
INCREMENT BY   1
NOCACHE
NOCYCLE;
CREATE OR REPLACE TYPE documents_q AS OBJECT
(
doc_id      NUMBER,
description VARCHAR2(1000),
CONSTRUCTOR FUNCTION documents_q(p_description VARCHAR2) RETURN SELF AS RESULT
);
CREATE OR REPLACE TYPE BODY documents_q AS
CONSTRUCTOR FUNCTION documents_q(p_description VARCHAR2) RETURN SELF AS RESULT IS
BEGIN
self.doc_id      := seq_documents.nextval;
self.description := p_description;
RETURN;
END;
END;
/
CREATE TYPE documents_t AS TABLE OF documents_q;
create table projects (
id NUMBER GENERATED ALWAYS AS IDENTITY ,
documents documents_t)
NESTED TABLE documents STORE AS documents_nested(
(PRIMARY KEY(nested_table_id, doc_id))  ORGANIZATION INDEX);
INSERT INTO PROJECTS(documents) VALUES (documents_t(documents_q('Description One'),documents_q('Description Two')));

SELECT * FROM projects;

如果它能给你解决方案，请告诉我。谢谢

Answer 2

如果您想要另一个没有构造函数的解决方案(因为使用构造函数增加了更多的维护(

我接受了@Sujithanty30的想法，并在insert语句中使用了序列。它使代码更易于维护，但迫使您在插入时使用sequence，并在每个查询中插入一个项(因为"sequence.nextval"在同一查询中不会增加(：

CREATE SEQUENCE documents_seq NOCACHE;
/
CREATE TYPE document_type AS OBJECT (
doc_id      NUMBER,
description VARCHAR2(1000)
);
/
CREATE TYPE documents AS TABLE OF document_type;
/
create table projects_docs (
id NUMBER GENERATED ALWAYS AS IDENTITY ,
docs documents)
NESTED TABLE docs STORE AS docs_nested(
(PRIMARY KEY(nested_table_id, doc_id)) ORGANIZATION INDEX); 
/
INSERT INTO projects_docs (docs) VALUES(
documents(document_type(documents_seq.nextval, 'doc')));
/
select p.id, d.* from projects_docs p, table(p.docs) d;