sql - Oracle - 如何使用 FAST REFRESH 和 JOINS 创建物化 View

Question

所以我很确定 Oracle 支持这个，所以我不知道我做错了什么。此代码有效:

CREATE MATERIALIZED VIEW MV_Test
  NOLOGGING
  CACHE
  BUILD IMMEDIATE 
  REFRESH FAST ON COMMIT 
  AS
    SELECT V.* FROM TPM_PROJECTVERSION V;

如果我添加一个 JOIN，它会中断:

CREATE MATERIALIZED VIEW MV_Test
  NOLOGGING
  CACHE
  BUILD IMMEDIATE 
  REFRESH FAST ON COMMIT 
  AS
    SELECT V.*, P.* FROM TPM_PROJECTVERSION V
    INNER JOIN TPM_PROJECT P ON P.PROJECTID = V.PROJECTID

现在我得到错误:

ORA-12054: 无法为物化 View 设置 ON COMMIT 刷新属性

我已经在 TPM_PROJECT 和 TPM_PROJECTVERSION 上创建了物化 View 日志。 TPM_PROJECT 的主键为 PROJECTID，TPM_PROJECTVERSION 的复合主键为 (PROJECTID,VERSIONID)。这有什么诀窍？我一直在挖掘 Oracle 手册，但无济于事。谢谢!

Answer 1

首先，来自 Oracle Database Data Warehousing Guide :

Restrictions on Fast Refresh on Materialized Views with Joins Only

...

• Rowids of all the tables in the FROM list must appear in the SELECT list of the query.

这意味着您的声明需要看起来像这样:

CREATE MATERIALIZED VIEW MV_Test
  NOLOGGING
  CACHE
  BUILD IMMEDIATE 
  REFRESH FAST ON COMMIT 
  AS
    SELECT V.*, P.*, V.ROWID as V_ROWID, P.ROWID as P_ROWID 
    FROM TPM_PROJECTVERSION V,
         TPM_PROJECT P 
    WHERE P.PROJECTID = V.PROJECTID

另一个需要注意的关键方面是您的物化 View 日志必须创建为 with rowid。

下面是一个功能测试场景:

CREATE TABLE foo(foo NUMBER, CONSTRAINT foo_pk PRIMARY KEY(foo));

CREATE MATERIALIZED VIEW LOG ON foo WITH ROWID;

CREATE TABLE bar(foo NUMBER, bar NUMBER, CONSTRAINT bar_pk PRIMARY KEY(foo, bar));

CREATE MATERIALIZED VIEW LOG ON bar WITH ROWID;

CREATE MATERIALIZED VIEW foo_bar
  NOLOGGING
  CACHE
  BUILD IMMEDIATE
  REFRESH FAST ON COMMIT  AS SELECT foo.foo, 
                                    bar.bar, 
                                    foo.ROWID AS foo_rowid, 
                                    bar.ROWID AS bar_rowid 
                               FROM foo, bar
                              WHERE foo.foo = bar.foo;