Siebel Tools >  How to extend a table

This was done using Siebel Local Database and Siebel Tools version 8.1.1.3.
In Siebel Tools, go to Table. Query for column Base Table =is null
and Name = S_*

Select table S_ACCNT_POSTN.
Lock the project.
Select Table-> Column tab from Object explorer for S_ACCNT_POSTN
Add a column -
Name = ACCNT_SIZE
Physical Type = Varchar
Length = 10

The name will be automatically changed to X_ACCNT_SIZE
This is because Siebel prefixes all extended columns with an X_ before.
Click on another column to save.
The design has been changed, we now need to change the database structure.
If you open SQL plus and type desc S_ACCNT_POSTN, this column will not be visible.

Select Table -> S_ACCNT_POSTN
Press the button Apply/DDL.

Select Generate DDL and press OK. You will see an apply schema Dialog box

Fill in these values
Tables = Current Row
Database user = siebel
Database user password = siebel_password
ODBC data source = SSD Local Db default instance
DDL file = D:\s_accnt_postn.txt

Press Generate DDL after this.

After some time, the file D:\s_accnt_postn.txt should be generated. It should contain an SQL that adds the column

In Siebel, click on Apply/DDL again and select Apply this time.
After this you should be able to see this column in S_ACCNT_POSTN table.

In real life, mostly you will be creating a repository export and someone will import both the ddl and repository.
DDLs contain changes in the database structure (not data itself). These changes are done using ddlsync.
There are several ways to do a ddl sync - through ADM, using UCF (universal configuration files) or commands
in the servermanager - ddlimp and ddldict.