Identifying Attributes › Identifying Attribute Characteristics

Identifying Attribute Characteristics

Attribute characteristics

At this time, you can identify characteristics of the attributes you have listed. Attribute characteristics include:

• Length
• Type (alphanumeric or numeric)
• Nullability

Null values

Sometimes you do not know the data associated with a particular attribute. The attribute might not be applicable to a particular entity occurrence, such as the phone number of an employee with no phone. Or the data simply might not be known yet, such as the credit rating of a new customer. Such attributes should allow null values. An attribute that does not allow null values requires that data always be entered.