Oracle 1Z0-909 問題集

質問 1：
Examine this statement which executes successfully:

The table is populated with a range of values including jobs for Robert, John, and Katie. Now, examine this statement and output:

Why is an empty result set returned?
A. The json_extract() function requires a length value that matches the field length in the schema.
B. Table statistics must be updated to generate values for the name column.
C. The select requires json_unquoteo in the where clause.
D. The virtual values in the name column must be accessed using functions.
E. The JSON datatype cannot be used in virtual columns.
正解：E

質問 2：
Examine the contents of these tables:

Now examine the expected results for a user with privileges to access the table:

Which query returns the expected results?
A)

B)

C)

D)

A. Option A
B. Option C
C. Option D
D. Option B
正解：D

質問 3：
Examine these statements issued from Session 1 which execute successfully:

Now, examine these statements issued from Session 2 which execute successfully:
Session 2>
BEGIN;
UPDATE band SET song=CONCAT ("Here Comes the ", song) WHERE song LIKE ' %Sun ; Which two are true?
A. Session 1 must commit before the update in Session 2 can complete.
B. Session 2 does not start a transaction.
C. Statements in Session 2 are committed.
D. Session 2 takes an exclusive lock on all the rows in the band table.
E. Session 1 takes a shared lock on all the rows in the band table.
F. Session 1 does not block Session 2.
正解：A,C

質問 4：
The collection col contains all episodes for all seasons for a TV show.
Examine this document which has an example of the details for each episode:

Which query returns all expisode names from the first season?
A. SELECT doc->,,$.name,, FROM col WHERE doc->"$ . season" = "1";
B. SELECT name FROM col WHERE season = 1;
C. SELECT doc->"$.name" FROM col WHERE doc->"$.season" = "1";
D. SELECT "S.name" FROM col WHERE "S.season" = "1";
正解：D

質問 5：
Examine these commands and output:


Which is true about the execution of the insert statement?
A. It inserts a new row in the base table only.
B. It returns an error.
C. It inserts a new row in the view only.
D. It inserts a row in the view and base table.
正解：C

質問 6：
Examine the appointments table definition which contains one million rows:

Now, examine this statement which executes successfully:

Which statement will improve query performance?
A. ALTER TABLE appointments add index IX_2(attendant_session_id, created_by)
B. ALTER TABLE appointments add index IX_1(credit,payment)
C. ALTER TABLE appointments add index IX_4<attendant_id, payment, credit)
D. ALTER TABLE appointments add index IX_3(attendant_id, created_by)
正解：C