How can I create a copy of an Oracle table without copying the data?

StackOverflow https://stackoverflow.com/questions/233870

Question

I know the statement:

create table xyz_new as select * from xyz;

Which copies the structure and the data, but what if I just want the structure?

Was it helpful?

Solution

Just use a where clause that won't select any rows:

create table xyz_new as select * from xyz where 1=0;

Limitations

The following things will not be copied to the new table:

  • sequences
  • triggers
  • indexes
  • some constraints may not be copied
  • materialized view logs

This also does not handle partitions

OTHER TIPS

I used the method that you accepted a lot, but as someone pointed out it doesn't duplicate constraints (except for NOT NULL, I think).

A more advanced method if you want to duplicate the full structure is:

SET LONG 5000
SELECT dbms_metadata.get_ddl( 'TABLE', 'MY_TABLE_NAME' ) FROM DUAL;

This will give you the full create statement text which you can modify as you wish for creating the new table. You would have to change the names of the table and all constraints of course.

(You could also do this in older versions using EXP/IMP, but it's much easier now.)

Edited to add If the table you are after is in a different schema:

SELECT dbms_metadata.get_ddl( 'TABLE', 'MY_TABLE_NAME', 'OTHER_SCHEMA_NAME' ) FROM DUAL;

Using sql developer select the table and click on the DDL tab

You can use that code to create a new table with no data when you run it in a sql worksheet

sqldeveloper is a free to use app from oracle.

If the table has sequences or triggers the ddl will sometimes generate those for you too. You just have to be careful what order you make them in and know when to turn the triggers on or off.

create table xyz_new as select * from xyz where rownum = -1;

To avoid iterate again and again and insert nothing based on the condition where 1=2

    DECLARE
    l_ddl   VARCHAR2 (32767);
BEGIN
    l_ddl      := REPLACE (
                      REPLACE (
                          DBMS_LOB.SUBSTR (DBMS_METADATA.get_ddl ('TABLE', 'ACTIVITY_LOG', 'OLDSCHEMA'))
                        , q'["OLDSCHEMA"]'
                        , q'["NEWSCHEMA"]'
                      )
                    , q'["OLDTABLSPACE"]'
                    , q'["NEWTABLESPACE"]'
                  );

    EXECUTE IMMEDIATE l_ddl;
END;

You can do this Create table New_table as select * from Old_table where 1=2 ; but be careful The table you create dose not have any Index , Pk and so on like the old_table

SELECT * INTO newtable
FROM oldtable
WHERE 1 = 0;

Create a new, empty table using the schema of another. Just add a WHERE clause that causes the query to return no data:

Simply write a query like:

create table new_table as select * from old_table where 1=2;

where new_table is the name of the new table that you want to create and old_table is the name of the existing table whose structure you want to copy, this will copy only structure.

WHERE 1 = 0 or similar false conditions work, but I dislike how they look. Marginally cleaner code for Oracle 12c+ IMHO is

CREATE TABLE bar AS SELECT * FROM foo FETCH FIRST 0 ROWS ONLY;

Same limitations apply: only column definitions and their nullability are copied into a new table.

you can also do a 

create table abc_new as select * from abc;

then truncate the table abc_new. Hope this will suffice your requirement.

Create table target_table 
As
Select * 
from source_table 
where 1=2;

Source_table is the table u wanna copy the structure of.

Using pl/sql developer you can right click on the table_name either in the sql workspace or in the object explorer, than click on "view" and than click "view sql" which generates the sql script to create the table along with all the constraints, indexes, partitions etc..

Next you run the script using the new_table_name

In other way you can get ddl of table creation from command listed below, and execute the creation.

SELECT DBMS_METADATA.GET_DDL('TYPE','OBJECT_NAME','DATA_BASE_USER') TEXT FROM DUAL 

TYPE is ('TABLE','PROCEDURE', etc...)

With this command you can get majority of ddl from database objects.

copy without table data

create table <target_table> as select * from <source_table> where 1=2;

copy with table data

create table <target_table> as select * from <source_table>;

The task above can be completed in two simple steps.

STEP 1:

CREATE table new_table_name AS(Select * from old_table_name);

The query above creates a duplicate of a table (with contents as well).

To get the structure, delete the contents of the table using.

STEP 2:

DELETE * FROM new_table_name.

Hope this solves your problem. And thanks to the earlier posts. Gave me a lot of insight.

Licensed under: CC-BY-SA with attribution
Not affiliated with StackOverflow
scroll top