Oracle SQL 在嵌套 table 中创建标识列

Question

我正在制作一个包含嵌套 table:

的 table

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);

这工作正常，但我似乎无法找到如何将嵌套 table 的主键作为标识列。有什么建议么？谢谢

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;

如果它能为您提供解决方案，请告诉我。谢谢

Answer 2

如果你想要另一个没有构造函数的解决方案（因为使用构造函数会增加更多维护）

我采纳了@Sujitmohanty30 的想法并在插入语句中使用了序列。它使代码更易于维护，但强制您在插入时使用序列并在每个查询中插入一项（因为“sequence.nextval”不会在同一查询中递增）：

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;

Oracle SQL 在嵌套 table 中创建标识列

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