1. A sintaxe “generated as identity” foi incluída para definição de chave autoincremento na definição das tabelas. (V)
=> The 12c database introduces the ability define an identity clause against a table column defined using a numeric type.
2. Na versão 12c, os tipos varchar, varchar2 e CHAR VARYING permitem que a coluna tenha no máximo 2.000 bytes. (F)
VARCHAR Maximum size: 4000 bytes
VARCHAR2 Maximum size: 4000 bytes
CHAR VARYING Maximum size: 4000 bytes
3. Colunas invisíveis podem ser definidas de forma que não apareçam nos resultados de consultas com (1) “SELECT * FROM” ou (2) DESCRIBE e são ignoradas nas instruções (3) INSERT quando não explicitadas na lista de colunas. (V)
In Oracle Database 12c, table columns can be defined as invisible either during its creation with the CREATE TABLE command or by modifying existing table columns via the ALTER TABLE statement. Among other operations, the following ones will not display or work with invisible table columns:
(1) SELECT * FROM in SQL instructions
(2) The DESCRIBE statement when used in either SQL*PLUS or via Oracle Call Interface (OCI)
...By Default, invisible columns do not show up when the DESCRIBE statement is issued against the table:
(3) While being invisible, the column can still be accessed via DML and DDL statements ...However, when performing inserts into
tables containing invisible columns, the column list must be defined in the statement. Failing to do so, will result in an ORA-00913 error.
4. Nessa versão, os identificadores tiveram o número de dígitos significativos aumentados de 30 para 128 caracteres. (V)
=> Oracle 12.2 increases the maximum size of most identifiers from 30 to 128 bytes, which makes migration from other database engines easier.
GABARITO C => 1,3,4 (V)
https://oracle-base.com/articles/12c
http://www.oracle.com/technetwork/articles/database/invisible-columns-odb12c-2331522.html
https://docs.oracle.com/cd/B28359_01/server.111/b28320/limits001.htm#i287903