Oracle Create Table AS和表注释以及列注释 [英] Oracle Create Table AS and table comments and column comments

问题描述

是否可以创建另一个表作为CREATE TABLE AS并保留列的注释?

Is it possible to create another table as CREATE TABLE AS and also preserve columns' comments ?

CREATE TABLE TABLE1_COPY AS SELECT * FROM TABLE1;

CREATE TABLE TABLE1_COPY AS SELECT * FROM TABLE1;

上一条语句不包含列的注释.因此，TABLE1_COPY保留无列注释.使用USER_COL_COMMENTS也是在我新创建的表上重现相同注释的唯一方法吗?

The previous statement does not include columns' comments. Therefore TABLE1_COPY is left without columns' comments. Is using USER_COL_COMMENTS the only way to reproduce the same comments on my newly created table too?

推荐答案

至于DMBS_METADATA.GET_DDL，它似乎没有产生COMMENT ON 除非缺少某些属性，否则使用COLUMN语句.

As for DMBS_METADATA.GET_DDL it doesn't seem to genereate COMMENT ON COLUMN statements unless I am missing some properties.

一种方法是将dbms_metadata.get_dependent_ddl与dbms_metadata.get_ddl结合使用

One method is to use dbms_metadata.get_dependent_ddl in combination with dbms_metadata.get_ddl

以下是使用SQL plus创建的示例:

Here is an example created using SQL plus:

SQL> set long 1000000

SQL> create table t (x number);

Table created.

SQL> comment on column T.X IS 'this is the column comment';

Comment created.

SQL> comment on table T IS 'this is the table comment';

Comment created.

SQL> SELECT dbms_metadata.get_ddl( 'TABLE', 'T' ) || ' ' ||
  2         dbms_metadata.get_dependent_ddl( 'COMMENT', 'T', USER ) the_ddl
  3  FROM dual
  4  /

THE_DDL
--------------------------------------------------------------------------------

  CREATE TABLE "SCOTT"."T"
   (    "X" NUMBER
   ) SEGMENT CREATION DEFERRED
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
  TABLESPACE "USERS"

   COMMENT ON COLUMN "SCOTT"."T"."X" IS 'this is the column comment'

   COMMENT ON TABLE "SCOTT"."T"  IS 'this is the table comment'

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