DAT 390 Wk 4 – Practice: Reading

Accurately complete the 4.1 to 4.7 Reading, Participation, and Challenge Activities to receive full points for this practice. You have unlimited attempts. The points you see in zyBooks do not reflect the points you receive in the gradebook.

Simple types

Since the 1980s, relational database products have supported six broad categories of data types:

• Integertypes represent positive and negative integers.
• Decimaltypes represent numbers with fractional values.
• Charactertypes represent textual characters. Character types may be either fixed-length or variable-length strings, consisting of either single-byte (ASCII) or double-byte (Unicode) characters.
• Timetypes represent date, time, or both. Some time types include a time zone or specify a time interval.
• Binarytypes store data exactly as the data appears in memory or computer files, bit for bit. Ex: Binary types may be used to store images.
• Semantictypes are based on other types but have a special meaning and functions. Ex: MONEY has decimal values representing currency. BOOLEAN has values zero and one representing false and true. UUID has string values representing Universally Unique Identifiers, such as a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11. ENUM has a fixed set of string values specified by the database designer, such as ‘red’, ‘green’, ‘blue’.

The above types have relatively simple internal structures and thus are called simple data types. Ex: A character value consists of a series of individual characters. Ex: A date value has three parts, year, month, and day.

Database functions can decompose the internal structure into separate values. Ex: If BirthDate has type date, the SQL function month(BirthDate) might return the birth month. From the perspective of arithmetic and comparison operators, however, the internal structure is ignored and each value is considered atomic.