OCP-052 & 053部分答案解析

OCP~052

. GRANT ANY OBJECT PRIVILEGE(授予任何对象权限)：允许被授权人将其本身不拥有的对象的对象权限授予他人，但不能授予自己。

. ENABLE VALIDATE 无法输入违反约束的行，而且表中的所有行都符合约束

DISABLE NOVALIDATE 可以输入任何数据（无论是否符合要求），表中可能已经存在不合乎要求的数据

ENABLE NOVALIDATE 表中可以存在不合乎要求的数据，但现在输入的所有数据必须符合要求

DISABLE VALIDATE 这种情况不可能：表中所有数据都符合约束，但新行未必如此。最终结果是针对DML命令锁定表

. 共享池主要包括以下4个组件:库缓存（库缓存是内存区域，按其已分析的格式存储最近执行的代码）；数据字典缓存（它存储最近使用的对象定义：表、索引、用户和其他元数据定义的描述）；PL/SQL区（存储的PL/SQL对象是过程、函数、打包的过程、打包的函数、对象类型定义和触发器。它们全都像源代码那种存储在数据字典中，也使用已编译的个数）；SQL查询和PL/SQL函数结果缓存

.

UNDO_TABLESPACE specifies the undo tablespace to be used when an instance starts up. If this parameter is specified when the instance is in manual undo management mode, then an error will occur and startup will fail.

If the UNDO_TABLESPACE parameter is omitted, the first available undo tablespace in the database is chosen. If no undo tablespace is available, the instance will start without an undo tablespace. In such cases, user transactions will be executed using the SYSTEM rollback segment. You should avoid running in this mode under normal circumstances.

You can replace an undo tablespace with another undo tablespace while the instance is running.

. DB_EXTENDED：与DB的作用大体相同，不过包含生成审核记录的、具有绑定变量的SQL内容

. DRA只能用于单实例数据库的环境。它不能用于RAC群集数据库，也不能用于Data Guard备用数据库

.

1.tnsping 命令可以检查tcp协议是否已通，俗称我们说的网络通不通

2.tnsping命令监听服务器上的监听是否已开启

3.tnsping命令不检测服务器上的监听的服务名，所以tnsping通，不代表就能连通。

OCP~053

.

1> SEC_PROTOCOL_ERROR_FURTHER_ACTION specifies the further execution of a server process when receiving bad packets from a possibly malicious client.

2> SEC_PROTOCOL_ERROR_FURTHER_ACTION = { CONTINUE | (DELAY,integer) | (DROP,integer) }

3> (DROP,integer)

The server forcefully terminates the client connection after integer cumulative bad packets. The server protects itself at the expense of the client (for example, a client transaction may be lost). The client may reconnect and attempt the same operation.

.

1> DB_SECUREFILE specifies whether or not to treat LOB files as SecureFiles.DB_SECUREFILE = { NEVER | PERMITTED | ALWAYS | IGNORE }

2> DB_ULTRA_SAFE sets the default values for other parameters that control protection levels.DB_ULTRA_SAFE = { OFF | DATA_ONLY | DATA_AND_INDEX },

• DATA_ONLY

  • DB_BLOCK_CHECKING will be set to MEDIUM.

  • DB_LOST_WRITE_PROTECT will be set to TYPICAL.

  • DB_BLOCK_CHECKSUM will be set to FULL.

. Baseline Templates

You can also create baselines for a contiguous time period in the future using baseline templates. There are two types of baseline templates: single and repeating.

You can use a single baseline template to create a baseline for a single contiguous time period in the future. This technique is useful if you know beforehand of a time period that you intend to capture in the future. For example, you may want to capture the AWR data during a system test that is scheduled for the upcoming weekend. In this case, you can create a single baseline template to automatically capture the time period when the test occurs.

You can use a repeating baseline template to create and drop baselines based on a repeating time schedule. This is useful if you want Oracle Database to automatically capture a contiguous time period on an ongoing basis. For example, you may want to capture the AWR data during every Monday morning for a month. In this case, you can create a repeating baseline template to automatically create baselines on a repeating schedule for every Monday, and automatically remove older baselines after a specified expiration interval, such as one month.

. 手动管理SGA的参数如下：SHARED_POOL_SIZE,DB_CACHE_SIZE,LARGE_POOL_SIZE,STREAMS_POOL_SIZE,JAVA_POOL_SIZE。要启用     SGA自动管理，则需要将上述参数设置为0，并设置SGA_TARGET来启用自动共享内存管理（automatic shared memory management，ASSM）

. CHANGE FAILURE in RMAN,enables you to change priority or close failures recorded in the Automatic Diagnostic Repository.

. Health Monitor是一组检查，会在特定错误条件出现时自动运行，也可以根据DBA的指示以手动方式运行。检查结果不存储在数据库，而存储在文件系统 中。其原因在于，一些错误的性质决定了数据库不再可用：因此，需要一个外部知识库来存储Health Monitor的结果。该知识库就是ADR。

只能在不同阶段运行不同的Health Monitor检查：

在nomount阶段，仅运行“DB Structure Integrity”检查，而且它只检查控制文件的完成性。

在mount阶段，“DB Structure Integrity”检查将检查控制文件、联机重做日志文件和数据文件头的完整性，还可运行“Redo Integrity Check”，以检查联机和归档日志文件的可访问性及其是否受损。

在open阶段，可能运行扫描每个数据块是否受损的检查，并检查数据字典和撤销段的完整性。

. RMAN supports two basic types of duplication: active database duplication and backup-based duplication