Recently we had a situation when two developers were working on same DB package. Delay in submission of deployment request by one dev resulted in package compilation error as a dependent Type was missing.
I was looking for solution that may help us avoid such situations in future.

Using SVN is one option; other is use of Database Change Management / Database Diff
Some tools for that are –

1) Oracle Change Management Pack
From the docs –
There are three core capabilities of Change Management that allow developers and database administrators to manage changes in database environments:
• Baseline – A point in time of the definition of the database and its associated database objects.
• Comparison – A complete list of differences between a baseline or a database and another baseline or a database.
• Synchronization – The process of promoting changes from a database definition capture in a baseline or from a database to a target database

It allows us to take a baseline(snapshot) at a fixed time and then later we can see how the DB schema and objects have changed. The CMP can also generate DDL scripts, though I am not sure we would want to use it.

Details
• http://download-east.oracle.com/docs/cd/B19306_01/em.102/b31949/change_management.htm
•http://www.oracle.com/technology/products/oem/pdf/change-management-pack-11g-datasheet.pdf

2) PL/SQL Developer Compare User Objects feature
This is available from Tools -> Compare User Objects

3) Oracle SQL Developer Database Diff feature
This is available from Tools -> Database diff
http://www.oracle.com/technology/products/database/sql_developer/files/what_is_sqldev.html#copy See “Schema Copy and Compare”

#1 looks to be most versatile and flexible but DBA rights may be necessary.
#2 & 3 can be used by any developer. I think Oracle SQL Developer is easier and provides more options.

Using any of the above option can help in –
1) Identifying the changed objects and may also serve as a Check List before requesting deployment.

2) The developers concerned can take ownership of specific changed objects.