Friday , June 23 2017

Last Articles

Managing Resources with Profiles

Managing Resources with Profiles A profile is a named set of resource limits and password parameters that restrict database usage and instance resources for a user. You can assign a profile to each user, and a default profile to all others. Each user can have only one profile, and creating …

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Managing Security for Oracle Database Users

Managing Security for Oracle Database Users About User Security Each Oracle database has a list of valid database users. To access a database, a user must run a database application, and connect to the database instance using a valid user name defined in the database. Oracle Database enables you to …

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Database Links

Database Links The central concept in distributed database systems is a database link. A database link is a connection between two physical database servers that allows a client to access them as one logical database. What Are Database Links? A database link is a pointer that defines a one-way communication …

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Distributed Database Concepts

Distributed Database Concepts Distributed Database Architecture A distributed database system allows applications to access data from local and remote databases. In a homogeneous distributed database system, each database is an Oracle Database. In a heterogeneous distributed database system, at least one of the databases is not an Oracle Database. Distributed …

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Managing Indexes

Managing Indexes About Indexes Indexes are optional structures associated with tables and clusters that allow SQL queries to execute more quickly against a table. Oracle Database provides several indexing schemes that provide complementary performance functionality. These are: ■B-tree indexes: the default and the most common ■B-tree cluster indexes: defined specifically …

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Managing Index-Organized Tables

Managing Index-Organized Tables What Are Index-Organized Tables? An index-organized table has a storage organization that is a variant of a primary B-tree. Unlike an ordinary (heap-organized) table whose data is stored as an un ordered collection (heap), data for an index-organized table is stored in a B-tree index structure in …

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Oracle 10G Recylce Bin Features

What Is the Recycle Bin? The recycle bin is actually a data dictionary table containing information about dropped objects. Dropped tables and any associated objects such as indexes, constraints, nested tables, and the likes are not removed and still occupy space. They continue to count against user space quotas, until …

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Automatic Memory Management

Automatic Memory Management The simplest way to manage instance memory is to allow the Oracle Database instance to automatically manage and tune it for you. To do so (on most platforms), you set only a target memory size initialization parameter (MEMORY_TARGET) and optionally a maximum memory size initialization parameter (MEMORY_MAX_TARGET). …

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Shared Server Architecture

Shared Server Architecture In a shared server architecture, a dispatcher directs multiple incoming network session requests to a pool of shared server processes, eliminating the need for a dedicated server process for each connection. An idle shared server process from the pool picks up a request from a common queue. …

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Overview of Background Processes

Overview of Background Processes Process Monitor Process (PM ON) The process monitor (PM ON) monitors the other background processes and performs process recovery when a server or dispatcher process terminates abnormally. PM ON is responsible for cleaning up the database buffer cache and freeing resources that the client process was …

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