My Experiences re: Migrating SQL Server Database to Oracle

Question

I am using SQL Developer EA4 for thsi conversion, best attempt yet.
I had numerous problems with this conversion.
1. The wizard asked me to specify the new Oracle database; instead it just ignored this information and created an Oracle database similarly named as the SQL Server database. I also noticed a file name "Migration.out" was produced; it contained errors such as:
Error starting at line 3 in command:
CREATE USER Emulation IDENTIFIED BY Emulation DEFAULT TABLESPACE USERS TEMPORARY TABLESPACE TEMP
Error at Command Line:3 Column:36
Error report:
SQL Error: ORA-01031: insufficient privileges
01031. 00000 - "insufficient privileges" and
Error starting at line 4 in command:
GRANT CREATE SESSION, RESOURCE, CREATE VIEW, CREATE MATERIALIZED VIEW, CREATE SYNONYM,CREATE PUBLIC SYNONYM TO Emulation
Error report:
SQL Error: ORA-01031: insufficient privileges
01031. 00000 - "insufficient privileges" and
Error starting at line 7 in command:
CREATE USER dbo_COREv13 IDENTIFIED BY dbo_COREv13 DEFAULT TABLESPACE USERS TEMPORARY TABLESPACE TEMP
Error at Command Line:7 Column:38
Error report:
SQL Error: ORA-01031: insufficient privileges
01031. 00000 - "insufficient privileges" and
Error starting at line 8 in command:
GRANT CREATE SESSION, RESOURCE, CREATE VIEW, CREATE MATERIALIZED VIEW, CREATE SYNONYM TO dbo_COREv13
Error report:
SQL Error: ORA-01031: insufficient privileges
01031. 00000 - "insufficient privileges".
I followed all of the steps listed in the "Help" section re: Migrations but still ended up with these errors.
2. My schema consists of 1000+ tables; approximately 10 tables were NOT created. When I copied the SQL from Migration.sql making NO changes and pasted it into the new Oracle database it created without issues.
3. While the conversion is taking place, different objects (constraints, indexes, foreign keys, etc) are shown to be copied; their appears to be ordering of these items. Shouln't a dependancy tree be established, and object converted based on this?
4. Several tables, in my case about 250 tables did NOT get any data copied across. No reasons given.
5. A log of all activities should be produced for review and completeness.
6. I tried to use the "Migrate select tables" option but met with no success. Apparently, it makes an assumption that both the "source" and "target" databases wil be of the same type (ie both SQL Server or both Oracle); this does not make any sense to me since the point of the exercise is to migrate data from one database vendor to another. Obviously, different database vendors use differing datatypes for similar data (ie dates).
7. I noticed in the "Migration" sql that the "Connect" statements are not correct; they were missing the "instance name" portion.
8. Also, when I looked in the "MIGRATION" sql, I could not find any entries for the last step of the conversion - the movement of data from SQL Server to Oracle. Is this intentional or an oversight.
I dont want to appear negative on this Migration; I have used SQL Developer since it inception; in my opinion this is the best attempt to date.
Murray Sobol

Answer 1

Hi Murray,
Thanks for this feedback.
There is a lot of questions here, I think some of it boils down to misunderstandings, which we should clarify in the doc.
Hopefully Ill get a video of a migration online soon as well.
But here is a brief break down.
*1.*
"The wizard asked me to specify the new Oracle database; instead it just ignored this information and created an Oracle database similarly named as the SQL Server database."
So this relates to Step 7 of the Migration Wizard. Where you can select the target connection.
SQL Developer doesn't ignore the Target Connection you selected, It just uses it to connect to the target database , not the target schema.
SQL Developer generates a new target schema for the migrated objects. It standard approach is not to generate objects directly into an existing Schema.
The Target Connection is used to create all the migrated objects (including new Oracle Schemas) in your target oracle database. So you should choose an Oracle Target Connection which has enough privileges to create new Schemas and Objects.
But as you have found, it doesn't generate the migrate objects , like tables, ... , directly into your chosen Target Connection.
From the errors you encountered it doesn't sound like the Target Connection (and the underling Oracle Schema) doesn't have the privileges to create other Schemas.
If you use something like a connection to the SYSTEM schema on your target database, it should run OK.
It wont create any objects in SYSTEM, rather it will use SYSTEM privileges to create a new schema (ex: dbo_Northwind) and populate it.
You don't have to use SYSTEM, but you do need a schema with enough privileges to create other schemas.
That is the straight forward way. But if you really need to generate into an existing schema the following steps can be taken.
a)rename the schema under the Converted Database Objects
b)Right click "Converted Databases Objects" and choose generate. it will kick off the Migration Wizard in the correct place
*2.*
My schema consists of 1000+ tables; approximately 10 tables were NOT created. When I copied the SQL from Migration.sql making NO changes and pasted it into the new Oracle database it created without issues.
When you say Migration.sql , is the entire generation file , which can be found in your <outputspecified>/generated/<projectname.modelname>.sql ?
When your say "pasted it into the new Oracle database" , are you running it in SQL Developers SQL Worksheet using the Target Connection.
Basically your migration is all out of shape once the target Schemas are not created. So the above issues (insufficient privileges) has to be resolved first.
Please post back if it is still an issue.
*3.*
While the conversion is taking place, different objects (constraints, indexes, foreign keys, etc) are shown to be copied; their appears to be ordering of these items. Shouln't a dependancy tree be established, and object converted based on this?
Objects are converted in a particular order and their dependencies are persisted so that they can be generated in the correct order.
Are you seeing an issue?
*4.*
Several tables, in my case about 250 tables did NOT get any data copied across. No reasons given.
I'm surprised any tables were populated with data due to the target schema not being created.
The online data move is pretty simple and it does not report or recover very well from issues.
If you are having difficulties once item 1. is resolved, please post an example of the source table and I will give it a go.
For better control of the data move with much more powerful tweaking, error handling, reporting and performance try the offline data move.
SQL Developer can created a suite of scripts which use SQL Servers BCP tool to dump out the data to dat files, and Oracle SQL*Loader tool to insert the data in the dat file into Oracle.
*5.*
A log of all activities should be produced for review and completeness.
The output/generated/<projectname.modelname>.out provides the output of running the generation script.
The migration reports http://dermotoneill.blogspot.com/2010/11/migration-reports-30.html outline what happens during the migration.
Apart from online data move issues, is there any other data missing?
*6.*
I tried to use the "Migrate select tables" option but met with no success. Apparently, it makes an assumption that both the "source" and "target" databases wil be of the same type (ie both SQL Server or both Oracle); this does not make any sense to me since the point of the exercise is to migrate data from one database vendor to another. Obviously, different database vendors use differing datatypes for similar data (ie dates).
Do you mean "Copy To Oracle" ? This option is intended to migrate tables from non Oracle databases like SQL Server to Oracle.
Can you give more details on what issue you are seeing.
*7.*
I noticed in the "Migration" sql that the "Connect" statements are not correct; they were missing the "instance name" portion.
The generation script is meant to be run using SQL Developers SQL Worksheet. I think you only get this "instance name" issue if running from SQL*Plus.
Can you confirm
8. Also, when I looked in the "MIGRATION" sql, I could not find any entries for the last step of the conversion - the movement of data from SQL Server to Oracle. Is this intentional or an oversight.
The online data move is performed separately from creating the objects. It is not script based, it uses JDBC to pump the data from the source database to the target database.
In summary , I would
a) Create a connection to your Target database using your SYSTEM schema
b) Right click on your "Converted Database Objects" and choose "Generate Target"
c) Choose your new "System" connection as the Target Connection
d) Follow the Migration Wizard to the end.
You will end up with a new target Schema and the migrated objects in it.
Check the .out file to see the errors
and the migration reports http://dermotoneill.blogspot.com/2010/11/migration-reports-30.html
Regards,
Dermot
SQL Developer Team.