Modifying Tables

You can modify tables using the SQL ALTER TABLE statement. You may need to change the table structure due to any of the following reasons:

• You omitted a column.
• Your column definition needs to be changed.
• You need to remove columns.

The ALTER TABLE statement is used to:

• Add a new column
• Modify an existing column
• Define a default value for the new column
• Drop a column
• Manage constraints

In Oracle Database XE, you can modify tables:

• Using the Object Browser
• Using the SQL Workshop tool