The datatype of a value associates a fixed set of properties with the value.These properties cause Oracle to treat values of one datatype differently from values of another. When you create a table or cluster, you must specify a datatype for each of its columns.When you create a procedure or stored function, you must specify a datatype for each of its arguments.
For example, columns cannot accept the value February 29 (except for a leap year) or the values 2 or 'SHOE'.
Each value subsequently placed in a column assumes the datatype of the column.
For example, if you insert value after verifying that it translates to a valid date.
Oracle Database provides a number of built-in datatypes as well as several categories for user-defined types that can be used as datatypes.
Do not confuse built-in datatypes and user-defined types with external datatypes.
For information on external datatypes, including how Oracle converts between them and built-in datatypes or user-defined types, see ::= Description of the illustration rowid_The ANSI-supported datatypes appear in the figure that follows.
"ANSI, DB2, and SQL/DS Datatypes" discusses the mapping of ANSI-supported datatypes to Oracle built-in datatypes.
The table that follows summarizes Oracle built-in datatypes.
The syntax of Oracle datatypes appears in the diagrams that follow.