Oracle Basic

Ad-Hoc Query:
This use of the Latin term means an impromptu, simple query.

Block:
A block is the smallest unit of storage in an Oracle database.The Oracle block size is configurable with the minimum size being 2KB and the maximum size being 16KB.

Bottleneck:
In computer terms, a bottleneck is a system component that limits the performance of the system.

Buffer:
Buffers can be used as a copy of data for quick read access.The buffers used to temporarily store redo entries until they can be written to disk are known as redo log buffers.

Cache:
A cache is a storage area used to provide fast access to data.

Checkpoint:
A checkpoint is an operation that forces all changed, in-memory data blocks to be written out to disk.

Clean Buffer:
A clean buffer is a buffer that has not been modified

Concurrency:
This term refers to the capability to perform many functions at the same time.

Database:
A database is a set of data, organized for easy access.

Data Dictionary:
The data dictionary is a set of tables Oracle uses to maintain information about the database.

DBA (Database Administrator):
The DBA is the person responsible for the operation, configuration, and performance of the database.

DBMS:
The Database Management System is the software and collection of tools that manages the database.

RDBMS:
A Relational Database Management System is a DBMS that is relational in nature.

DDL (Data Definition Language) Commands:
These commands are used in the creation and modification of schema objects.

Dirty Buffer:
A dirty buffer is a buffer that has been modified. It is the job of the DBWR to eventually write all dirty block buffers out to disk.

DML (Data Manipulation Language) Commands:
These commands allow you to query and modify data within existing schema objects.

Dynamic Performance Tables:
These tables are created at instance startup and used to store information about the performance of the instance.

Function:
A function is a set of SQL or PL/SQL statements used together to execute a particular function.

IM (Information Management) or IS (Information Systems):
This term is usually used to describe the department that handles your corporate data.

IT (Information Technology):
This term is used to describe the business of managing information.

Network Computing Architecture (NCA):
The Network Computing Architecture is a standard for computing over the network

Physical Memory:
This term refers to the actual hardware RAM (Random Access Memory) available in the computer for use by the operating system and applications.

Procedure:
A procedure is a set of SQL or PL/SQL statements used together to execute a particular function.

Program Unit:
In Oracle, program unit is used to describe a package, a stored procedure, or a sequence.

Query:
A query is a read-only transaction against a database.

Schema:
A schema is a collection of objects associated with the database.

Schema Objects:
Schema objects are abstractions or logical structures that refer to database objects or structures.

System Global Area (SGA):
The SGA is a shared-memory region that Oracle uses to store data and control information for one Oracle instance

Transaction:
A transaction is a logical unit of work consisting of one or more SQL statements.

Trigger:
A trigger is a mechanism that allows you to write procedures that are automatically executed whenever an INSERT, UPDATE, or DELETE statement is executed on a table or view.

Storage Units:
Data is stored in the computer in a binary form. follows:
Term Definition Comment
bit The smallest unit of data storage
A bit is either a 1 or a 0.
nibble 4 bits
byte 8 bits
A word is 16 bits
kilobyte (KB) is 1024 bytes
megabyte (MB is 1,024KB
A gigabyte is 1,024 megabytes.
A terabyte is 1,024 gigabytes or

OLTP:
OLTP systems have online users that access the system. These systems are typically used for order-entry purposes, such as for retail sales, credit-card validation, ATM transactions, and so on.

DSS:
The Decision Support System (DSS) is used to assist with the decision-making process.

Data Warehouse:
A data warehouse is typically considered to be a large-scale system that consists of both DSS and OLTP components.

Data Mart:
A data mart, which is a smaller-scale version of a data warehouse, serves many of the same functions as a data warehouse.

Video Server:
A video server can support large numbers of video data streams. These video streams can be used for urposes such as video on demand for entertainment as well as training functions.

Web Server:
The Oracle Web server is designed to support both static and dynamic Web pages.

OLAP:
The term OLAP (Online Analytical Processing) is usually used in relation with multidimensional data.