问题
I use oracle 11, and use exp/imp tools to migrate data between databases.
It works very fine IF all empty tables and sequences are already created in target database.
But If tables dont exists in target DB than a few bad things happen;
- It still creates tables but only the ones with data, I couldnt find a way to force it create empty tables in target DB.
- It does not create the sequences.
This is how I enter my values to export tool;
Users or Tables -> Tables
Export table data -> yes
Compress -> yes
Table or Partition to be exported -> I enter table names here one by one,
But it does accept table names without data..It says table does not exist, so no surprize they are not imported later.
Import Data only > no
Import File > Full path to Dump file.
List contents of import file > no
Ignore create error > no
import grants > yes
import table data > yes
import entire export > yes
回答1:
Sequences are not exported in table mode. The documentation lists the objects exported in each mode, and that shows that sequences are only exported in user and full database modes.
Export is deprecated in 11g, as the documentation also states:
Original Export is desupported for general use as of Oracle Database 11g. The only supported use of original Export in Oracle Database 11g is backward migration of XMLType data to Oracle Database 10g release 2 (10.2) or earlier. Therefore, Oracle recommends that you use the new Data Pump Export and Import utilities
The empty tables are not being exported if you have deferred segment creation. This AskTom articles refers to it, and it's also mentioned in the documentation:
The original Export utility does not export any table that was created with deferred segment creation and has not had a segment created for it.
You can either use dbms_metadata.get_ddl() to get the table creation statements for all the tables, or just the empty ones, and build them manually from that; or force an extent to be allocated (as mentioned in the docs too); or use the supported and current data pump export and import. Based on previous questions you should only be using exp/imp if your customer refuses to handle data pump files, and I can't really think of a good justification for that.
来源：https://stackoverflow.com/questions/22857177/oracle-export-tool-does-not-create-some-tables-and-sequences