Go Up to Working with Tables
ALTER TABLE to modify the structure of an existing table.
ALTER TABLE allows you to:
- Add a new column to a table.
- Drop a column from a table.
- Drop integrity constraints from a table or column.
- Modify the column name, data type, and position.
You can perform any number of the above operations with a single
ALTER TABLE statement. A table can be altered by its creator, the SYSDBA user, and any users with operating system root privileges.
- Note: Any one table (and its triggers) can be altered at most 255 times before you must back up and restore the database.