Explicit and Implicit Casts

Processing queries with multiple data types often requires casts that convert data from one data type to another.

You can use the CREATE CAST statement to create the following kinds of casts:
  • Use the CREATE EXPLICIT CAST statement to define an explicit cast.
  • Use the CREATE IMPLICIT CAST statement to define an implicit cast.

The database server invokes built-in casts to convert from one built-in data type to another built-in type that is not directly substitutable. For example, the database server performs conversion of a character type such as CHAR to a numeric type such as INTEGER through a built-in cast.