dwh terminolgy i-o

I

Indexing fastest searching records

Information Data that has been processed in such a way that it can increase the knowledge of the person who receives it.

Information Systems Architecture The authoritative definition of the business rules, systems structure, technical

framework, and product backbone for business information systems.

Instance a set of values representing a specific entity belonging to a particular entity type.

Integrity a set of values representing a specific property of a data base that ensures that the data contained in the

data base in accurate and consistent as possible.

Intelligent Data Base a data base that contains shared logic as well as shared data and automatically invokes that logic

when the data base is accessed. Logic, constraints, and controls relating to the use of data are represented in an

intelligent data model.

Interleaved Data data from different tables mixed into a simple table space where is commonality of physical

colocation based on a common key value.

Iterative Analysis the mode of processing in which the next step of processing depends on the results obtained by the

existing step in execution.


J
Join an operation that takes two relations as operands and produces a new relation by concatenating the tuples and

matching the corresponding columns when a stated condition holds between the two.


K
Key Compression a technique for reducing the number of bits in keys; used in making indexes occupy less space.


L
Latency is often used to mean any delay or waiting that increases real or perceived response time beyond the response time

desired.

Load After extracting, cleaning and transforming, data must be loaded into the warehouse. Additional preprocessing may

still be required: checking integrity constraints; sorting; summarization, aggregation and other computation to build the

derived tables stored in the warehouse; building indices and other access paths; and partitionaing to multiple target storage

areas. Load utilities can be used for these operations.

Lockup the event that occurs when update is done against a data base record and the transaction has not yet reached a commit

point.

Logging the automatic recording of data with regard to the access of the data, the updates to the data, etc.

Logical Representation a data view or description that does not depend on a physical storage device or a computer program.


M
Main Storage Data Base (msdb) a data base that resides entirely in main storage. Such data bases are very fast to access,

but require special handling at the time of update. MSDB's can only manage a small amounts of data.

Maximum Transaction Arrival Rate (MTAR) the rate of arrival of transactions at the moment of peak period processing.

MDDB Multi Dimensional DataBase

Metadata or Meta Data Metadata is data about data. Examples of metadata include data element descriptions, data type

descriptions, attribute/property descriptions, range/domain descriptions, and process/method descriptions. The repository

environment encompasses all corporate metadata resources: database catalogs, data dictionaries, and navigation services.
Metadata includes things like the name, length, valid values, and description of a data element. Metadata is stored in a data

dictionary and repository. It insulates the data warehouse from changes in the schema of operational systems.

Metadata Synchronization The process of consolidating, relating and synchronizing data elements with the same or

similar meaning from different systems. Metadata synchronization joins these differing elements together in the data

warehouse to allow for easier access.

Metalanguage a language used to specify other languages.

Methodology A system of principles, practices, and procedures applied to a specific branch of knowledge.

Mid-Tier Data Warehouses To be scalable, any particular implementation of the data access environment may incorporate

several intermediate distribution tiers in the data warehouse network. These intermediate tiers act as source data warehouses

for geographically isolated sharable data that is needed across several business functions.

Middleware A communications layer that allows applications to interact across hardware and network environments.

Migration the process by which frequently used items of data are moved to more readily accessible areas of storage and

infrequently used items of data are moved to less readily accessible areas of storage.

MOLAP OLAP on Multidimensional models. In MOLAP servers, Data warehouses directly store multidimensional data in special

data structures(eg.,arrays) and implement the OLAP operations over these special data structures.

Multilist Organization a chained file organization in which the chains are divided into fragments and each fragment is

indexed. This organization of data permits faster access to the data.


N
Natural Join a join in which the redundant logic components generated by the join are removed.

Network Model a data model that provides data relationships on the basis of records or groups of records (ie. sets) in

which one record is designated as the set owner, and a single member record can belong to one or more sets.

Nonprocedural Language syntax that directs the computer as to what to do, not how to do it. Typical nonprocedural languages

include RAMIS,FOCUS, NOMAD, and SQL.

Normalization Normalization is a step-by-step process of removing redundancies and dependencies of attributes in a data

structure. The condition of the data at completion of each step is described as a "normal form." Thus, when normalizing we

talk about data as being in the first normal form, the second normal form, etc. Normalization theory identifies normal forms

up to at least the fifth normal form, plus an adjunct form known as Boyce-Codd Normal Form (BCNF). The first three forms are

sufficient to meet the needs of warehousing data models.


O
OLAP (On-Line Analytical Processing) Describes the systems used not for application delivery, but for analyzing the

business, e.g., sales forecasting, market trends analysis, etc. These systems are also more conducive to heuristic reporting

and often involves multidimensional data analysis capabilities.

OLTP (OnLine Transaction Processing) Describes the activities and systems associated with a company's day-to-day

operational processing and data (order entry, invoicing, general ledger, etc.).

Operational Data Store (ODS) the form that data warehouse takes in the operational environment. Operational data stores

can be updated, do provide rapid and consistent time, and contain only a limited amount of historical data.

Overflow the condition in which a record or a segment cannot be stored in its home because the address is already

occupied.