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Users with explicit object privileges and the SYSDBA can access dictionary objects. If, however, you need access to dictionary objects and do not have explicit object privileges, you can be granted the following roles: * SELECT_CATALOG_ROLE Enables users to SELECT all exported catalog views and tables granted to this role. Grant this role to users who must access all exported views and tables in the data dictionary. * EXECUTE_CATALOG_ROLE Provides EXECUTE priv

Status of the log member:■ INVALID - File is inaccessible■ STALE - File's contents are incomplete■ DELETED - File is no longer used■ null - File is in use[@more@]

Log status:■ UNUSED - Online redo log has never been written to. This is the stateof a redo log that was just added, or just after a RESETLOGS, when itis not the current redo log.■ CURRENT - Current redo log. This implies that the redo log is active.The redo log could be open or closed.■ ACTIVE - Log is active but is not the current log. It is needed forcrash recovery. It may be in use for block recovery. It may or may notbe archived.■ CLEARING - Log is being re-created as an empty log after

Specify KEEP INDEX or DROP INDEX to indicatewhether Oracle Database should preserve or drop the index it has been using toenforce the PRIMARY KEY or UNIQUE constraint.[@more@]

ensures that all new DML operations on the constrained data comply with the constraint. This clause does not ensure that existing data in the table complies with the constraint and therefore does not require a table lock.[@more@]

specifies that all old and new data also complies with the constraint. An enabled validated constraint guarantees that all data is and will continue to be valid. If any row in the table violates the integrity constraint, the constraint remains disabled and Oracle returns an error. If all rows comply with the constraint, Oracle enables the constraint. Subsequently, if new data violates the constraint, Oracle does not execute the statement and returns an error indicating the integrity con

Specify ENABLE if you want the constraint to be applied to the datain the table.If you enable a unique or primary key constraint, and if no index exists on the key,then Oracle Database creates a unique index. Unless you specify KEEP INDEX whensubsequently disabling the constraint, this index is dropped and the database rebuildsthe index every time the constraint is reenabled.You can also avoid rebuilding the index and eliminate redundant indexes by creatingnew primary key and unique constraints

Oracle iAS的英文全称是Oracle Internet Application Server，即Internet应用服务器，Oracle iAS是基于Java的应用服务器，通过与Oracle 数据库等产品的结合，Oracle iAS能够满足Internet应用对可靠性、可用性和可伸缩性的要求。　　Oracle iAS最大的优势是其集成性和通用性，它是一个集成的、通用的中间件产品。在集成性方面，Oracle iAS将业界最流行的HTTP服务器Apache集成到系统中，集成了Apache的Oracle iAS通信服务层可以处理多种客户请求，包括来自Web浏览器、胖客户端和手持设备的请求，并且根据请求的具体内容，将它们分发给不

ORA-00027 cannot kill current sessionCauseAn attempt was made to use ALTER SYSTEM KILL SESSION to kill the current session.ActionIf it is necessary to kill the current session, do so from another session.[@more@]

■ STARTED - After STARTUP NOMOUNT■ MOUNTED - After STARTUP MOUNT or ALTER DATABASE CLOSE■ OPEN - After STARTUP or ALTER DATABASE OPEN■ OPEN MIGRATE - After ALTER DATABASE OPEN { UPGRADE | DOWNGRADE }[@more@]

CREATE TABLE * NOROWDEPENDENCIES | ROWDEPENDENCIESThis clause lets you specify whether table will use row-level dependency tracking.With this feature, each row in the table has a system change number (SCN) thatrepresents a time greater than or equal to the commit time of the last transaction that modified the row. You cannot change this setting after table is created.ROWDEPENDENCIES Specify ROWDEPENDENCIES if you want to enable row-leveldependency tracking. This setting is useful primarily to al

Dropping a database involves removing its datafiles, redo log files, control files, and initialization parameter files. The DROP DATABASE statement deletes all control files and all other database files listed in the control file. To use the DROP DATABASE statement successfully, all of the following conditions must apply:■ The database must be mounted and closed.■ The database must be mounted exclusively--not in shared mode.■ The database must be mounted as RESTRICTED.An example of this state

If database creation fails, you can look at the alert log to determine the reason for the failure and to determine corrective action.You should shut down the instance and delete any files created by the CREATE DATABASE statement before you attempt to create it again. After correcting the error that caused the failure of the database creation, try re-creating the database.[@more@]

Note: Oracle no longer offers licensing by the number of concurrent sessions. Therefore the LICENSE_MAX_SESSIONS and LICENSE_SESSIONS_WARNING initialization parameters are no longer needed and have been deprecated. If you use named user licensing, Oracle Database can help you enforce this form of licensing. You can set a limit on the number of users created in the database. Once this limit is reached, you cannot create more users.Note: This mechanism assumes that each person accessing the databa

The COMPATIBLE initialization parameter enables or disables the use of features in thedatabase that affect file format on disk. For example, if you create an Oracle Database 10g database, but specify COMPATIBLE = 9.2.0.2 in the initialization parameter file, then features that requires 10.0 compatibility will generate an error if you try to use them. Such a database is said to be at the 9.2.0.2 compatibility level.You can advance the compatibility level of your database. If you do advance the co

The UNDO_MANAGEMENT initialization parameter determines whether an instance starts in automatic undo management mode which stores undo in an undo tablespace. By default, this parameter is set to MANUAL. Set this parameter to AUTO to enable automatic undo management mode.[@more@]

Every Oracle Database must have a method of maintaining information that is used to undo changes to the database. Such information consists of records of the actions of transactions, primarily before they are committed. Collectively these records are called undo data.This section provides instructions for setting up an environment for automatic undo management using an undo tablespace.[@more@]

The PROCESSES initialization parameter determines the maximum number of operating system processes that can be connected to Oracle Database concurrently. The value of this parameter must be a minimum of one for each background process plus one for each user process. The number of background processes will vary according the database features that you are using. For example, if you are using Advanced Queuing or the file mapping feature, you will have additional background processes. If you are us

V$SGA : Displays summary information about the system global area (SGA).V$SGAINFO : Displays size information about the SGA, including the sizes of different SGA components, the granule size, and free memory.V$SGASTAT : Displays detailed information about the SGA.V$SGA_DYNAMIC_COMPONENTS : Displays information about the dynamic SGA components. This view summarizes information based on all completed SGA resize operations since

The STREAMS_POOL_SIZE initialization parameter is a dynamic parameter that lets you specify or adjust the size of the Streams Pool component of the SGA. If STREAMS_POOL_SIZE is set to 0, then the Oracle Streams product transfers memory from the buffer cache to the Streams Pool when it is needed. For details, see the discussion of the Streams Pool in Oracle Streams Concepts and Administration[@more@]