An attribute is a data field representing a characteristic or feature of a data object or an entity like Customer, Store items etc. The nouns attribute, dimensions, feature, nd variable are often used interchangably in the industry. The term dimension is common in the data warehousing world, feature in machine learning, variable in statistics and attribute in data mining and databases.
Name, address, and ID is the attributes of the customer object.
1. Nominal Attribute – The values of a nominal attribute are symbols or names of things. Each value represents some kind of category, code or state. Nominal attributes are also known as categorical.
- Example- Hair color is a nominal attribute of person object, possible values are black, brown, blond, red etc.
2. Binary Attribute – A binary attibute is a nominal attribute with only two categorical values or states, 0 and 1
Example- Smoker attribute of person object is a binary attribute with values 1 indicates person smokes and 0 indicates non-smoker.
Symmetric vs asymmetric Binary Attributes
Symmetric– both of its states are equally valuable and carry the same weight. Gender is a symmetric attribute with values male and female.
Asymmetric – the outcomes of the states are not equally important. the positive and negative outcome of a medical test for HIV is an example.
3.Ordinal Attributes – Are attributes with possible values that have a meaningful order or ranking among them, but the magnitude between the successive values is not known. Customer satisfaction is an example with ordinal values, Very dissatisfied, Somewhat dissatisfied, neutral, satisfied and very satisfied.
4. Numeric Attributes – Are quantitative attributes which are measurable quantities represented in integer or real values. Numeric Attributes are generally interval or ratio scaled.
Interval-scaled– are measured on a scale of equal size units. Temperature is an example
Ratio-Scaled – have an inherent zero point. years of experience is an example
5. Discrete Attributes – A discrete attribute has a finite or countably infinite set of values, which may or may not be represented as integers. Hair Color and Smoker attributes are examples
6. Continuous Attributes – A continuous attribute can have any value. weight is an example.