Any idea about these extra tables in my development schema?

Question

I'm on Oracle 11gR2. In Development environment I have a schema DEV3 and I'm seeing a lot of extra tables. I'm wondering what or who created these tables. If anyone has any idea please share with me.

Also what will be happen if I drop these tables?

Some of extra tables' names are given below:

AB,
AL,
BCB, 
BCF, 
...
MD_ADDITIONAL_PROPERTIES, 
MD_CATALOGS 
MD_COLUMNS 
MD_CONNECTIONS
MD_CONSTRAINT_DETAILS
MD_CONSTRAINTS 
MD_DERIVATIVES
MD_GROUP_MEMBERS 
MD_GROUP_PRIVILEGES 

There are a lot of other tables starting MD_ .

Answer 1

Those are tables for the Migration Workbench. You would see them if you have used SQL Developer to move, say, a MySQL database to Oracle. Probably they should have been installed in a dedicated schema rather than a random development account.

If you're not aware of having installed Migration Workbench (it's not a default) I suggest you ask your colleagues before dropping them.

SQL Developer champion Jeff Smith maintains a site about Migration Workbench. Find out more.