19.Which three statements are true about Deferred Segment Creation in Oracle databases?
A.It is the default behavior for tables and indexes.
B.It is supported for sys-owned tables contained in locally managed tablespaces
C.Sessions may dynamically switch back and forth from DEFERRED to IMMEDIATE segment creation.

D.Indexes inherit the DEFERRED or IMMEDIATE segment creation attribute from their parent table
E.It is supported for Index Organized Tables(IOTs) contained in locally managed tablespaces.
answer ：ACD
Table types that are not supported for delay segment creation include ： Index organization table
user SYS、SYSTEM、PUBLIC、OUTLN and XDB The following table does not support delay segment creation .

20.Which two Oracle database space management features require the use of locally managed Table spaces?
A.Oracle Managed Files(OMF).
B.Server-generated tablespace space alerts
C.Online segment shrink
D.Free space management with bitmaps
E.Automatic data file extension (AUTOEXTEND)
answer ：CD

21.Which three statements are true about data block storage in an Oracle Database?
A.An index block can contain row data
B.A data block header is of a fixed length
C.A table block must always contain row data
D.A block header contains a row directory pointing to all rows in the block.
E.Row data is stored starting at the end of the block
answer ：ADE

22.Which two are true about a SQL statement using SET operators such as UNION?
A.The data type of each column returned by the second query must exactly match the data type of the corresponding column returned by the first query
B.The number, but not names, of columns must be identical for all SELECT statements in the query
C.The names and number of columns must be identical for all SELECT statements in the query D.The data type of each column returned by the second query is automatically converted to the data
type of the corresponding column returned by the first query
E.The data type group of each column returned by the second query must match the data type group of the corresponding column returned by the first query
answer ：BE

23.Which two are benefits of external tables?
A.They support UPDATES which transparently updates records in the file system as if they were table
B.They can be queried while the database is in the MOUNT state like dynamic performance views C.They support DELETEs which transparently deletes records in the file system as if they were table rows
D.The results of a complex join or aggregating function or both can be unloaded to a file for transportation to another database
E.They can be queried, transformed, and joined with other tables without having to load the data first

answer ：DE
The external table can do any query operation , The advantage is that you don't need to load it into the database , But it does not support any
Of dml operation .

need OCP Please add the exam materials I created qq Group