A well-crafted architecture will also help you work more efficiently. The same is true for
databases. Despite the name “Oracle”, there is no magic!
The architecture that Oracle has built its database around is designed to perform quickly,
efficiently and without errors.
In this section we will introduce you to the Oracle architecture. This architecture includes the
* The System Global Area (SGA) and other memory areas that utilize RAM
* Database related background processes
* Tablespaces and Datafiles
* Database related files
* The instance and the database
FEATURES IN ORACLE
Scalability and Performance
RAC Oracle Real Application Clusters (RAC) — an option for the Oracle
Database software produced by Oracle Corporation and introduced in 2001 with Oracle9i —
provides software for clustering and high availability in Oracle database environments
Self managing database
OEM Oracle Enterprise Manager (OEM or EM) aims to manage software produced
by Oracle Corporation as well as by some non-Oracle entities.
ASM Automatic Storage Management (ASM) is a new feature that has be introduced in
Oracle 10g to simplify the storage of Oracle datafiles, controlfiles and logfiles.
Backup and Recovery
Oracle Ultra Search
Information Integration Features
Database Replay Partitioning
Explore Database Replay, the new tool that Learn about Referential, Internal, and Virtual Column
captures SQL statements and lets you replay them at partitioning; new sub-partitioning options; and more.
Transaction Management Schema Management
Get an introduction to Flashback Data Archive Add columns with a default value easily and explore
and explore Enterprise Manager's LogMiner interface. invisible indexes, virtual columns, and read only tables.
SQL Plan Management SQL Performance Analyzer
Use bind variables that pick the right plan Accurately assess the impact of rewriting of SQL
every time and ensure a new execution plan is perfect statements and get suggested improvements.
before it's used.
SQL Access Advisor PL/SQL: Efficient Coding
Get advice about optimal table design based Triggers that fire several times at different events and
on actual use of the table, not just data. ability to force triggers of the same type to follow a sequence
are some new gems.
Explore Data Recovery Advisor, do parallel Learn about Tablespace Encryption, case-sensitive
backup of the same file, and create and manage virtual passwords, data masking, and other features.
Automatic Storage Management Manageability
Learn about new SYSASM role, variable Explore automatic memory management, multicolumn
extent sizes, and other ASM improvements. statistics, online patching, and more features.
Caching and Pooling SQL Operations: Pivot and Unpivot
Explore SQL Result Cache, PL/SQL Function Present information in a spreadsheet-type crosstab
Cache, and Database Resident Connection Pooling. report from any relational table using simple SQL, and store any
data from a crosstab table to a relational table.
Explore next-generation LOBs: LOB Explore Automatic Health Monitor, Automatic
encryption, compression, deduplication, and Diagnostic Repository, and other new resiliency features.
Data Guard PL/SQL Performance
Query the physical standby database in real Explore in-lining of code, "real" native compilation,
time without shutting down recovery, just for starters. PLS timer, use of simple integer, and more.
Data Warehousing and OLAP And Don't Forget...
Get a tour of new features in these areas, COPY command, Export/Imports, Data Pump
including Cube Organized MVs. improvements, and more.
Distributed Database Architecture
A distributed database system allows applications to access data from local and
remote databases. In a homogenous 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 databases use
a client/server architecture to process information requests.
This section contains the following topics:
Homogenous Distributed Database Systems
A homogenous distributed database system is a network of two or more Oracle
Databases that reside on one or more machines.
Heterogeneous Distributed Database Systems
In a heterogeneous distributed database system, at least one of the databases is
a non-Oracle Database system. To the application, the heterogeneous distributed
database system appears as a single, local, Oracle Database. The local Oracle
Database server hides the distribution and heterogeneity of the data.
Client/Server Database Architecture
A database server is the Oracle software managing a database, and a client is an
application that requests information from a server. Each computer in a network
is a node that can host one or more databases. Each node in a distributed
database system can act as a client, a server, or both, depending on the
A Distributed database is a set of databases in a distributed system that can appear to
applications as a single data source.
Parallel execution is one of the fundamental database technologies that enable
organizations to manage and access terabytes of data. Without parallelism, these
large databases, commonly used for data warehouses but increasingly found in
operational systems as well, would not exist.
Simply defined, parallel execution is the ability to apply multiple CPU and IO
resources to the execution of a single database operation. While every major
database vendor today provides parallel capabilities, there remain key
differences in the architectures provided by the various vendors.
Data concurrency means that many users can access data at the same time.
Data consistency means that each user sees a consistent view of the data,
including visible changes made by the user's own transactions and
transactions of other users.