Invisible Columns in Oracle 12c

Invisible column is a new feature in Oracle 12c.  Invisible columns provide a convenient way to change a table’s structure without having to edit the existing applications using that table.   Invisible columns can be created at the time of table creation using CREATE TABLE command                                 SQL> create table inviscol_test                                 2  (compno number,                                 3  compname varchar(20),                                 4  compcode varchar(10) invisible);                                 Table created.   existing visible columns can be modified to invisible using ALTER TABLE command                                 SQL> alter table inviscol_test modify (compname invisible);                                 Table altered.   How does it work?   The insert statement where we don’t specify the column names will fail.                                 SQL> insert into inviscol_test values (101,’ABCD’,’A101′);                                 insert into inviscol_test values (101,’ABCD’,’A101′)                                 *                                 ERROR at line 1:                                 ORA-00913: too many values                                 Explicit column names should be included in the insert statement.                                 SQL>  insert into inviscol_test(compno, compname, compcode) values                                 (101,’ABCD’,’A101′);                                 1 row created.   If invisible columns are not listed in the insert statement they are set to NULL                                 SQL>  insert into inviscol_test values (201);                                 (more…)


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