Static, time-related columns can be added to tables by adding columns defined to have DateTime data types, such as DATE or TIMESTAMP. Teradata also supports two built-in time dimensions that can be used to create temporal tables: transaction time and valid time.
Each of these time dimensions is represented by a column with a period data type. The column stores a pair of DATE or TIMESTAMP values that define the beginning and end of the transaction- or valid-time period for a row. Transaction time and valid time are independent time dimensions. A table can have either type of column, both, or neither:
- A table with a transaction-time column is called a transaction-time table.
- A table with a valid-time column is called a valid-time table.
- A table with both a transaction-time and a valid-time column is called a bitemporal table.
- A table with neither a transaction-time nor a valid-time column is a nontemporal table.