Glossary - D

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data

• The material of a knowledge collection system used to create information
• The information stored in a database
• The representation of facts, texts, graphics, bitmap images, sound, video segments, etc...

data dictionary

• An information structure that defines the organization of a database including the list and description of each element of the database such as columns, data types, memory allocations for data storage, etc...

data files

• Files that contain actual data, rather than meta-data or other data descriptions. See meta-data and data.

data mart

• A departmental or subject-specific subset of data of a data warehouse. See data warehouse.

data mining

• The process of finding patterns or trends in a collection of data.

data modeling

• The development of rules that cover data entities (objects such as relationships, tables, columns, data integrity, etc.) of a database management system.

data set

• A collection of data entries where each entry contains a group of data items. Also called a table.

Data Source

• a collection of information used by the ODBC software to connect to a database, required before accessing databases from a container application such as Microsoft Word.

data source file

• An initialization file that stores the location of data on a server and the transport method used to access the data.

data source name (DSN)

• DSN; in ODBC, the name of the origin (e.g., of a file, database, document, etc.) of transmitted data.

data type

• The characteristic description of data, be it alphabetic, numeric, integer, decimal, character, string, etc.

data type discrepancy

• Condition in which data stored in a particular field does not match the DBMS data type defined for that field.

data warehouse

• A voluminous collection of summarized consistent data, usually historical in nature, used for only data analysis rather than data processing
• A database designed and optimized for OLAP.

database

• A collection of data files stored in a specific structure, whose organization is centrally defined in a root file or data dictionary.

database key

• A field or column that uniquely identifies a row in a table.

database tuning

• A process effected on a database by the database administrator (DBA) in an effort to improve the speed and efficiency of data retrievals and data throughput.

data-only option

• An option supported by the OmniAccess update routines (oainsert, oadelete, and oaupdate) that disables the real-time updating of OMNIDEX indexes. This option is useful when updating a high volume of records. Data-only updates must be followed by a DBINSTAL B or INDEX operation to update the OMNIDEX indexes.

DBA

• Database Administrator; person responsible for maintenance of a database system.

DBMS

• Database Management System; the file structure for the storage of data and the functions included in the maintenance of the data, such as transaction processing, table relationships, back-up and data restoration.

DCE

• Distributed Computing Environment; the term for the Open Software Foundation (OSF) standard of computer interoperability.

decompile

• in OMNIDEX, the process of reverting a compiled Environment Catalog file to an Environment source file using the utility OADECOMP.

denormalization

• the process of introducing duplication of data within a relational database (which is typically normalized), used in data warehouse applications to avoid the inefficiencies of cross-table join operations. See normalization.

detail data set

• Child table.

Detail Record

• a record in a child table. See DR Domain.

device driver

• a program that provides an interface between the operating system and a hardware device.

DI keys

• distributed index key. See distributed index.

dimension table

• A parent table with a unique key that provides keyed access into a child (fact) table;
• tables that contain descriptions for codes in fact tables.

direct access

• the process of locating a record or row based on its location on a storage device, which is fast but requires an exact key match. See hashed access and hashed key.

disconnect

• the process of terminating a network connection.

disk I/O

• See I/O.

distributed computing

• a hardware system architecture that spreads the computing load over multiple computers connected via a network.

distributed data

• the placement and maintenance of data at one or more data sites on a mainframe computer or across a telecommunications network.

distributed index

• An indexing option for Omnidex, or MDK indexes, in which the index is stored as a separate file, essentially creating an IMSAM, or ASK key;
• An ASK Index installed through an MDK Index process with ;DI option which can be used essentially as an MDK Index, including on-line index maintenance and optimization like an MDK Index, and also aggregation as on an ASK Index.

domain

• A parent table and any child tables that were linked (prejoined) to it during Omnidex installation;
• A single, unjoined table with Omnidex indexes installed on it;
• A a single data set installed with multiple keys;
• An association of several data sets installed with multiple keys and linked during installation. Also called an Omnidex domain. See SI domain and DR domain.

domain name server

• in TCP/IP, a server program that supplies name-to-address mapping by storing each network host's network address, domain name, and an optional alias.

DR

• See Detail Record.

DR domain

• an OMNIDEX domain that consists of one detail data set, or child table, that has not been linked to a master data set, or parent table. A DR domain child table can also be part of RS (Record Specific) domain. See Hybrid-DR domain and domain.

drill down

• In data analysis, the process of narrowing data to retrieve specific underlying detail;
• In OMNIDEX, successive iterations of adding criteria to a query, refining a search to the exact subset of required data.

Driver Manager

• Software written by Microsoft and installed when installing ODBC applications;
• Software accessed by container applications such as Excel which initiates the appropriate ODBC driver such as the OMNIDEX ODBC Driver.

DSN

• Data Source Name; see data source name

DSS

• Decision Support System; an application that provides information to a business analyst to identify organization options.
  
  

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