How can Oracle add default values to table fields?

To add a default value to a table column, you can use the ALTER TABLE statement to modify the table structure. Here is an example:

ALTER TABLE table_name
ALTER COLUMN column_name SET DEFAULT default_value;

In this example, the table_name refers to the name of the table you want to modify, the column_name is the name of the field where you want to add a default value, and default_value is the default value you want to set.

In addition, you can also specify a default value when creating the table, for example:

CREATE TABLE table_name (
    column_name data_type DEFAULT default_value
);

In this example, the default values for the fields were specified when the table was created.