Oracle 91 Software

Traditionally, the operating systems regulated resource management among the various applications running on a system, including Oracle databases. To manage the multiversion consistency model, Oracle must create a read-consistent set of data when a table is queried read and simultaneously updated written. Such statements should be in other transactions.

Partitioning addresses key issues in supporting very large tables and indexes by letting you decompose them into smaller and more manageable pieces called partitions. There is no relationship between a tablespace and a schema.

Oracle Database Architecture

Today, information tends to be fragmented across a company, making it difficult to see the business as a whole or answer basic questions. Oracle databases can be deployed anywhere in the world, and a single instance of an Oracle database can be accessed by users across the globe.

Oracle Background Processes An Oracle database uses memory structures and processes to manage and access the database. Procedures and functions are identical, except that functions always return a single value to the user. If a new protocol is used, then the database administrator makes some minor changes, while the application requires no modifications and continues to function. Every Oracle database has a control file.

Oracle Database Administrator's Guide. Oracle's lock manager automatically locks table data at the row level. This enables Oracle to provide an infrastructure for application developers to integrate data mining seamlessly with database applications. Online and Offline Tablespaces A tablespace can be online accessible or offline not accessible.

Partitioning is useful for many different types of applications, particularly applications that manage large volumes of data. Data Replication Replication is the maintenance of database objects in two or more databases. When an update occurs, the original data values changed by the update are recorded in the database undo records. These statements change the properties of the Oracle database instance. The Scheduler lets database administrators and application developers control when and where various tasks take place in the database environment.

If the consuming application is on a different database, then the events are automatically propagated to the appropriate database. Statements that start after the user's transaction is committed only see the changes made by the committed transaction.

Oracle 91 softwareOracle 91 software

For a partitioned index, each partition has an index segment. Trace file information is also used to tune applications and instances. Oracle Streams provides powerful replication features that can be used to keep multiple copies of distributed objects synchronized. Some operating systems use the terms job or task. This process remasters systemwide resources, recovers partial or failed transactions, and restores the system to normal, preferably within a matter of microseconds.

Data must adhere to certain business rules, as determined by the database administrator or application developer. Authorization processes to limit access and actions, limits that are linked to user's identities and roles. Each system in the distributed environment is called a node.

Because of this portability, you can easily upgrade to a more powerful server as your requirements change. Consider a banking database. They can be automatically applied with a user-defined function or database table operation, can be explicitly dequeued, or a notification can be sent to the consuming application. Overview of Da tabase Backup and Recovery Features In every database system, the possibility of a system or hardware failure always exists. Above extents, the level of logical database storage is a segment.

Oracle Streams implicitly and explicitly captures events and places them in the staging area. Oracle uses current information in the system global area and information in the undo records to construct a read-consistent view of a table's data for a query. The Server The server runs Oracle software and handles the functions required for concurrent, shared data access. Instance failure can result from a hardware problem such as a power outage, lingaa songs telugu or a software problem such as an operating system failure.

Oracle 9i Overview

The filled online redo log files are archived before they are reused in the cycle. In every database system, the possibility of a system or hardware failure always exists. When statement failure occurs, any effects of the statement are automatically undone by Oracle and control is returned to the user.

There are numerous background processes, and each Oracle instance can use several background processes. These statements let a user control the properties of the current session, including enabling and disabling roles and changing language settings. Introducing a Transparent Gateway into an Oracle Streams environment enables replication of data from an Oracle database to a non-Oracle database. Optionally, filled online redo files can be manually or automatically archived before being reused, creating archived redo logs. The computer that manages the server can be optimized for its duties.

The server runs Oracle software and handles the functions required for concurrent, shared data access. The client workstation can be optimized for its job. The unique key or primary key of the same or a different table referenced by a foreign key. Without adequate concurrency controls, data could be updated or changed improperly, compromising data integrity. It provides a unified framework for processing events.

With Oracle-managed files, bigfile tablespaces make datafiles completely transparent for users. Indexes Indexes are optional structures associated with tables. The Database Resource Manager controls the distribution of resources among various sessions by controlling the exec ution schedule inside the database. Datafiles Every Oracle database has one or more physical datafiles.

Archive Log Files You can en able automatic archiving of the redo log. To protect against a failure involving the redo log itself, Oracle allows a multiplexed redo log so that two or more copies of the redo log can be maintained on different disks. If a system uses the shared server or if the user and server processes run on different computers, then the user and server processes must be separate. Oracle ensures the integrity of data in a distributed transaction using the two-phase commit mechanism. By default, Oracle guarantees statement-level read consistency.

Rebalancing of the database's storage automatically occurs whenever the storage configuration changes. Database tables hold all user-accessible data. Rollback segment If you are operating in automatic undo management mode, then the database server manages undo space using tablespaces. For example, users may be geographically distributed, and fast data access may be more important for these users than access to an identical resource. By controlling which sessions run and for how long, the Database Resource Manager can ensure that resource distribution matches the plan directive and hence, the business objectives.

Features of Oracle 9i