Oracle's lack of a Bit datatype for table columns

Question

Oracle does not support a bit datatype or any other type for true/false scenarios. Does one use the char(1) field instead by using a specific letter to

Answer 1

Oracle internally uses "bits" (not a datatype per se) in different Data Dictionary views.

For example, dba_users view has :

..
        , DECODE (BITAND (u.spare1, 128), 128, 'YES', 'NO')
..
        , DECODE (BITAND (u.spare1, 256), 256, 'Y', 'N')
..

which shows a way to workaround this in a way. If you don't have to modify "boolean" bits often, you could employ the same approach that Oracle had since Oracle 6 (at least). Create a table with a NUMBER column, and a VIEW on top of that that hides complexity of BITAND operations.

ps. On a side note, Oracle JDBC has a "Bit" datatype https://docs.oracle.com/cd/E16338_01/appdev.112/e13995/oracle/jdbc/OracleTypes.html#BIT as well as you already know PL/SQL has Boolean. Although it probably doesn't help you much. See BITAND approach above if it suites your case.