Your database instance has the following parameter setting: OS_AUTHENT_PREFIX = OPS$
You execute the following command:

And then grant OPS$GUEST_USER the CREATE SESSION privilege. Which two statements are true? (Choose two.)

Correct Answer:CD

You want to create a file watcher and an event-based job for detecting the arrival of files on the local server from various locations. To achieve this, you enable the raising of file arrival events from remote systems.
Which two conditions must be satisfied to receive file arrival events from a remote system? (Choose two.)

Correct Answer:CD
References: https://docs.oracle.com/cd/E18283_01/server.112/e17120/scheduse005.htm

Examine the parameter for your database instance:

You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan:

Identify the reason why the optimizer chose different execution plans.

Correct Answer:A

Examine the following command: CREATE TABLE (prod_id number(4), Prod_name varchar2 (20), Category_id number(30),
Quantity_on_hand number (3) INVISIBLE);
Which three statements are true about using an invisible column in the PRODUCTS table? (Choose three.)

Correct Answer:ABE
AB: You can make individual table columns invisible. Any generic access of a table does not show the invisible columns in the table. For example, the following operations do not display invisible columns in the output:
* SELECT * FROM statements in SQL
* DESCRIBE commands in SQL*Plus
* %ROWTYPE attribute declarations in PL/SQL
* Describes in Oracle Call Interface (OCI) Incorrect: Not D: You can make invisible columns visible.
You can make a column invisible during table creation or when you add a column to a table, and you can later alter the table to make the same column visible.

The HR schema exists in two databases, BOSTON and DENVER, and has the same password, HR. You have the CREATE DATABASE LINK and CREATE SESSION privileges on both the database. BOSTON is defined as a service name in the tnsnames.ora of both the databases.
You plan to use the command:
CREATE DATABASE LINK hr_link CONNECT to hr IDENTIFIED BY hr USING 'denver';
What must be done to ensure only the HR user in the BOSTON database can access the HR schema in the DENVER database?

Correct Answer:D

Which two services may you see on the My Service Dashboard page? (Choose two.)

Correct Answer:CD