Solved

Oracle SQL Insert Script to copy data between tables

Posted on 2016-09-27
8
45 Views
Last Modified: 2016-09-27
Hi All,

I have created a simple insert query to move the contents of table A into table B (there is some additions made in this process).

INSERT INTO TABLE B (Col A, Col B, Col C, Col D)
SELECT Col A, Col B, Col C,'Fixed' FROM TABLE A

Open in new window


However, this scrambles the order of the rows.  The order is important because it represents a parent-child relationship.  What do I need to change to maintain the row order?

Thanks,
Mark
0
Comment
Question by:SuperLight
8 Comments
 
LVL 76

Expert Comment

by:slightwv (䄆 Netminder)
ID: 41817999
>>What do I need to change to maintain the row order?

Add an order by in the select?
0
 
LVL 34

Accepted Solution

by:
johnsone earned 500 total points
ID: 41818010
There is no order to rows in a table.  There is no order when they are retrieved from a table (only an ORDER BY guarantees that).  If you managed to get the rows into the table in some sort of order, then a simple update to one of the rows could easily change the order of the rows.
0
 
LVL 76

Expert Comment

by:slightwv (䄆 Netminder)
ID: 41818019
What johnsone said but I was creating a test case to show it.

Can you explain why you think insert order matters?  Are you getting some constraint error?

Here is a simple test showing the order doesn't matter:
drop table tab1 purge;
create table tab1
  (
     id      number primary key,
     child number references tab1(id)
  );

insert into tab1 values(1,1);
insert into tab1 values(2,1);
insert into tab1 values(3,2);
commit;



drop table tab2 purge;
create table tab2
  (
     id      number primary key,
     child number references tab2(id)
  );

insert into tab2 select * from tab1 order by child desc;
commit;

Open in new window

0
 

Author Comment

by:SuperLight
ID: 41818022
Thanks for the clarification!  Easy points ;o)
0
PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

 

Author Comment

by:SuperLight
ID: 41818024
For information, the table contains metadata that is used to build a hierarchy (Parent-Child format) therefore the order must be maintained otherwise the child will appear before the parent.

Thanks,
Mark
0
 
LVL 76

Expert Comment

by:slightwv (䄆 Netminder)
ID: 41818028
>> therefore the order must be maintained otherwise the child will appear before the parent.

Insert order shouldn't matter with an insert as select.  Look at the example I posted.

Now, if you were doing individual inserts then yes, you need to make sure the parent exists before the child.

If you still believe order is important, then why did you select the post that said it didn't matter?
0
 
LVL 8

Expert Comment

by:Ghunaima
ID: 41818527
Try changing line 22 to

insert into tab2 select * from tab1 order by I'd, child; commit;
0
 
LVL 76

Expert Comment

by:slightwv (䄆 Netminder)
ID: 41818540
Ghunaima,

First:  This question is closed.
Second:  You commented on a test case showing that in this case, insert order doesn't matter.  The order by in the test case was as I intended it.
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Join & Write a Comment

Suggested Solutions

Introduction A previously published article on Experts Exchange ("Joins in Oracle", http://www.experts-exchange.com/Database/Oracle/A_8249-Joins-in-Oracle.html) makes a statement about "Oracle proprietary" joins and mixes the join syntax with gen…
How to Create User-Defined Aggregates in Oracle Before we begin creating these things, what are user-defined aggregates?  They are a feature introduced in Oracle 9i that allows a developer to create his or her own functions like "SUM", "AVG", and…
Via a live example, show how to take different types of Oracle backups using RMAN.
This video shows how to copy an entire tablespace from one database to another database using Transportable Tablespace functionality.

746 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

13 Experts available now in Live!

Get 1:1 Help Now