Changing Table Properties 
You use the table editor to change the properties of a table.
Note
You can also use SQL statements instead of the table editor.
More information:
SQL Reference Manual, ALTER TABLE Statement (alter_table_statement)
Prerequisites
You are logged on to the database as a database user.
You have the ALTER privilege for the table.
More information: SQL Reference Manual, Privilege Specification (priv_spec)
The database is in the ONLINE operational state.
Procedure
In the context menu of the table, choose Definition.
NoteTo display the definition as an SQL statement, choose Export SQL in the context menu of the editor.
End of the note.In the context menu of the editor window, choose Edit.
Change the table definition.
More information: Creating Tables
In the context menu of the editor window, choose Alter Table.