Oracle 1Z0-873 Online Practice Questions and Exam Preparation

Oracle 1Z0-873 Online Questions & Answers

• Question 31:

  mysqldump can be instructed to dump...

  A. Only table structures
  B. Only data
  C. Both table structures and data
  C. Both table structures and data

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  32.4.2.

  The mysqldump client program dumps table contents to files. It can dump all databases, specific databases, or specific tables.

• Question 32:

  Which of the following statements are true for locks established by the InnoDB storage engine?

  A. It sometimes escalates locks to page level.
  B. It sometimes escalates locks to table level.
  C. It sometimes escalates locks to page or table level.
  D. It never escalates locks to page or table level.
  D. It never escalates locks to page or table level.

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  29.4.4.

  During the course of a transaction, InnoDB may acquire row locks as it discovers them to be necessary. However, it never escalates a lock (for example, by converting it to a page lock or table lock). This keeps lock contention to a minimum

  and improves concurrency.

• Question 33:

  Which of the following happens when BEGIN TRANSACTION or START TRANSACTION command is issued?

  A. Autocommit mode overrides BEGIN TRANSACTION and START TRANSACTION.
  B. Autocommit mode is suspended and has to be re-enabled explicitly.
  C. Autocommit mode is suspended until COMMIT.
  D. Nothing happens as they are not valid commands.
  C. Autocommit mode is suspended until COMMIT.

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  29.4.3. The InnoDB Transaction Model

  The second method is to suspend the current autocommit mode by beginning a transaction explicitly.

  Any of the following statements begins a transaction:

  START TRANSACTION;

  BEGIN;

  BEGIN WORK;

• Question 34:

  Which of the following package types are provided specifically for UNIX-style OS installations?

  A. Essentials
  B. RPM
  C. Source
  D. tar-packaged binary
  B. RPM

• Question 35:

  What three data components are needed for data recovery?

  A. The slow log.
  B. The backup log.
  C. The general log.
  D. The binary log.
  E. The data backup.
  F. configuration files.
  D. The binary log.
  E. The data backup.
  F. configuration files.

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  D:

  Incremental backups are made possible by enabling the server's binary log, which the server uses to record data changes.

  D:

  The data backup is the main component of a backup.

  F: A physical backup includes configuration files.

  Note: Logical backups save information represented as logical database structure (CREATE DATABASE, CREATE TABLE statements) and content (INSERT statements or delimited-text files). Physical backups consist of raw copies of the

  directories and files that store database contents.

  Logical backup methods have these characteristics:

  ?The backup is done by querying the MySQL server to obtain database structure and content information. ?Backup is slower than physical methods because the server must access database information and convert it to logical format. If the

  output is written on the client side, the server must also send it to the backup program.

  ?Output is larger than for physical backup, particularly when saved in text format. ?Backup and restore granularity is available at the server level (all databases), database level (all tables in a particular database), or table level. This is true

  regardless of storage engine. ?The backup does not include log or configuration files, or other database-related files that are not part of databases.

  Physical backup methods have these characteristics:

  ?The backup consists of exact copies of database directories and files. Typically this is a copy of all or part of the MySQL data directory.

  Data from MEMORY tables cannot be backed up this way because their contents are not stored on disk. ?Physical backup methods are faster than logical because they involve only file copying without conversion.

  ?Output is more compact than for logical backup.

  ?Backup and restore granularity ranges from the level of the entire data directory down to the level of individual files. This may or may not provide for table-level granularity, depending on storage engine. (Each MyISAM table corresponds

  uniquely to a set of files, but an InnoDB table shares file storage with other InnoDB tables.)

  ?In addition to databases, the backup can include any related files such as log or configuration files.

  References:

• Question 36:

  When making connections to a MySQL server on a Unix platform, which of the following is true?

  A. TCP/IP connections are faster than socket file connections.
  B. Socket file connections are faster than TCP/IP connections.
  C. TCP/IP and Socket file connections are equally as fast.
  B. Socket file connections are faster than TCP/IP connections.

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  23.2. Communication Protocols

  On Unix, a Unix socket file connection provides better performance than a TCP/IP connection.

• Question 37:

  Which of the following is true for the command-line programs mysqlcheck and myisamchk?

  A. mysqlcheck must run on the server to perform checks and repairs and myisamchk can perform checks and repairs on a remote server.
  B. mysqlcheck can perform checks and repairs on a remote server, and myisamchk must run on the server.
  C. Both mysqlcheck and myisamchk can perform checks and repairs on a remote server.
  D. Neither mysqlcheck or myisamchk can perform checks and repairs on a remote server.
  B. mysqlcheck can perform checks and repairs on a remote server, and myisamchk must run on the server.

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  30.3.

  The myisamchk utility for MyISAM tables also performs table maintenance. However, it takes a different approach from MySQL Administrator and mysqlcheck. Rather than sending SQL statements to the server, myisamchk directly reads and

  modified the table files. For this reason, it's necessary when using myisamchk to ensure that the server does not access the tables at the same time.

• Question 38:

  In which of the following files must the base directory be specified if MySQL is not installed in the default directory for the platform?

  A. config.cnf
  B. config.ini
  C. my.cnf
  D. my.ini
  E. basedir.cnf
  F. basedir.ini
  C. my.cnf
  D. my.ini

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  24.4. Runtime MySQL Configuration If you install MySQL on Windows, the server assumes by default that the installation directory is C:\mysql and the data directory is named data in the installation directory. If you install MySQL somewhere else, such as E:\mysql, you must tell the server that location with a --basedir option. Options in option files are given without the leading dashes, so to indicate the installation directory, specify the option as follows:

  [mysqld] basedir=E:/mysql

• Question 39:

  Which of the following are reasons to not just enable all logging?

  A. Security risks.
  B. More disk space is used.
  C. More memory is used.
  D. Slower performance.
  B. More disk space is used.
  D. Slower performance.

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  35.4. Log Files and Security

  Log exposure constitutes a security risk that must be addressed by protecting the log files, but logs also play a role in enhancing security. Certain logs, if enabled, provide data security or information that is useful in the event of attack:

• Question 40:

  Which of the following (series of) statements will leave the three tables A, B and C locked for reading, writing and reading respectively once all statements have been executed?

  A. mysql> LOCK TABLES A;mysql> LOCK TABLES B;mysql> LOCK TABLES C;
  B. mysql> LOCK TABLES A READ;mysql> LOCK TABLES B WRITE;mysql> LOCK TABLES C READ;
  C. mysql> LOCK TABLES A READ, B WRITE, C READ;
  D. LOCK TABLES A, B, C READ, WRITE, READ;
  C. mysql> LOCK TABLES A READ, B WRITE, C READ;

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  28.2. Explicit Table Locking If you need to use multiple tables while holding an explicit lock, you must lock all of them at the same time because you cannot use any unlocked tables while you hold explicit locks. Also, you must lock all the tables with a single LOCK TABLES statement. LOCK TABLES releases any locks that you already hold, so you cannot issue it multiple times to acquire multiple locks.