Answer: A,B,E 

Explanation: A: The APPEND keyword tells SQL*Loader to preserve any preexisting data in the table. Other options allow you to delete preexisting data, or to fail with an error if the table is not empty to begin with. 

B (not D): Note: 

* SQL*Loader-00210: first data file is empty, cannot process the FIELD NAMES record 

Cause: The data file listed in the next message was empty. Therefore, the FIELD NAMES 

FIRST FILE directive could not be processed. 

Action: Check the listed data file and fix it. Then retry the operation 

E: 

* A comma-separated values (CSV) (also sometimes called character-separated values, because the separator character does not have to be a comma) file stores tabular data (numbers and text) in plain-text form. Plain text means that the file is a sequence of characters, with no data that has to be interpreted instead, as binary numbers. A CSV file consists of any number of records, separated by line breaks of some kind; each record consists of fields, separated by some other character or string, most commonly a literal comma or tab. Usually, all records have an identical sequence of fields. 

* Fields with embedded commas must be quoted. 

Example: 

1997,Ford,E350,"Super, luxurious truck" 

Note: 

* SQL*Loader is a bulk loader utility used for moving data from external files into the Oracle database. 

Answer: C 

Answer: B 

Explanation: Step 1 (2). Seed column usage Oracle must observe a representative workload, in order to determine the appropriate column groups. Using the new procedure DBMS_STATS.SEED_COL_USAGE, you tell Oracle how long it should observe the workload. Step 2: (3) You don't need to execute all of the queries in your work during this window. You can simply run explain plan for some of your longer running queries to ensure column group information is recorded for these queries. Step 3. (1) Create the column groups At this point you can get Oracle to automatically create the column groups for each of the tables based on the usage information captured during the monitoring window. You simply have to call the DBMS_STATS.CREATE_EXTENDED_STATS function for each table.This function requires just two arguments, the schema name and the table name. From then on, statistics will be maintained for each column group whenever statistics are gathered on the table. 

Note: 

* DBMS_STATS.REPORT_COL_USAGE reports column usage information and records all the SQL operations the database has processed for a given object. 

* The Oracle SQL optimizer has always been ignorant of the implied relationships between data columns within the same table. While the optimizer has traditionally analyzed the distribution of values within a column, he does not collect value-based relationships between columns. 

* Creating extended statisticsHere are the steps to create extended statistics for related table columns withdbms_stats.created_extended_stats: 

1 - The first step is to create column histograms for the related columns.2 – Next, we run dbms_stats.create_extended_stats to relate the columns together. 

Unlike a traditional procedure that is invoked via an execute (“exec”) statement, Oracle extended statistics are created via a select statement. 

Answer: B 

Explanation: Once DDL logging is turned on, every DDL command will be logged in the alert log file and also the log.xml file. 

Note: 

* By default Oracle database does not log any DDL operations performed by any user. The default settings for auditing only logs DML operations. 

* Oracle 12c DDL Logging – ENABLE_DDL_LOGGING 

The first method is by using the enabling a DDL logging feature built into the database. By default it is turned off and you can turn it on by setting the value of ENABLE_DDL_LOGGING initialization parameter to true. 

* We can turn it on using the following command. The parameter is dynamic and you can 

turn it on/off on the go. 

SQL> alter system set ENABLE_DDL_LOGGING=true; 

System altered. Elapsed: 00:00:00.05 SQL> 

Once it is turned on, every DDL command will be logged in the alert log file and also the log.xml file. 

Answer: B,D,E 

Explanation: B, not A: The PDB must be closed before unplugging it. 

D: An unplugged PDB contains data dictionary tables, and some of the columns in these encode information in an endianness-sensitive way. There is no supported way to handle the conversion of such columns automatically. This means, quite simply, that an unplugged PDB cannot be moved across an endianness difference. 

E (not F): To exploit the new unplug/plug paradigm for patching the Oracle version most effectively, the source and destination CDBs should share a filesystem so that the PDB’s datafiles can remain in place. 

Reference: Oracle White Paper, Oracle Multitenant 

Answer: B,D 

Reference: http://docs.oracle.com/cd/E11882_01/server.112/e40540/logical.htm#CNCPT250 

Answer: B 

Explanation: * SHUTDOWN [ABORT | IMMEDIATE | NORMAL | TRANSACTIONAL [LOCAL]] 

Shuts down a currently running Oracle Database instance, optionally closing and dismounting a database. If the current database is a pluggable database, only the pluggable database is closed. The consolidated instance continues to run. 

Shutdown commands that wait for current calls to complete or users to disconnect such as SHUTDOWN NORMAL and SHUTDOWN TRANSACTIONAL have a time limit that the SHUTDOWN command will wait. If all events blocking the shutdown have not occurred within the time limit, the shutdown command cancels with the following message: 

ORA-01013: user requested cancel of current operation 

* If logged into a CDB, shutdown closes the CDB instance. 

To shutdown a CDB or non CDB, you must be connected to the CDB or non CDB instance that you want to close, and then enter 

SHUTDOWN 

Database closed. 

Database dismounted. 

Oracle instance shut down. 

To shutdown a PDB, you must log into the PDB to issue the SHUTDOWN command. 

SHUTDOWN 

Pluggable Database closed. 

Note: 

* Prerequisites for PDB Shutdown 

When the current container is a pluggable database (PDB), the SHUTDOWN command can only be used if: 

The current user has SYSDBA, SYSOPER, SYSBACKUP, or SYSDG system privilege. 

The privilege is either commonly granted or locally granted in the PDB. 

The current user exercises the privilege using AS SYSDBA, AS SYSOPER, AS 

SYSBACKUP, or AS SYSDG at connect time. To close a PDB, the PDB must be open. 

Answer: A 

Explanation: 

* Creating a PDB Rather than constructing the data dictionary tables that define an empty PDB from scratch, and then populating its Obj$ and Dependency$ tables, the empty PDB is created when the CDB is created. (Here, we use empty to mean containing no customer-created artifacts.) It is referred to as the seed PDB and has the name PDB$Seed. Every CDB non-negotiably contains a seed PDB; it is non-negotiably always open in read-only mode. This has no conceptual significance; rather, it is just an optimization device. The create PDB operation is implemented as a special case of the clone PDB operation. The size of the seed PDB is only about 1 gigabyte and it takes only a few seconds on a typical machine to copy it. 

Answer: B,D,E 

Explanation: During SQL execution, if a cardinality misestimate occurs, then the database creates SQL plan directives. During SQL compilation, the optimizer examines the query corresponding to the directive to determine whether missing extensions or histograms exist (D). The optimizer records any missing extensions. Subsequent DBMS_STATS calls collect statistics for the extensions. 

The optimizer uses dynamic sampling whenever it does not have sufficient statistics corresponding to the directive. (B, not C) 

E: Currently, the optimizer monitors only column groups. The optimizer does not create an extension on expressions. 

Incorrect: 

Not A: SQL plan directives are not tied to a specific SQL statement or SQL ID. 

Note: 

* A SQL plan directive is additional information and instructions that the optimizer can use to generate a more optimal plan. For example, a SQL plan directive can instruct the optimizer to record a missing extension. 

Answer: B,C