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A database is an organized collection of data. The term originated within the computer industry, but its meaning has been broadened by popular use, to the extent that the European Database Directive (which creates intellectual property rights for databases) includes non-electronic databases within its definition. This article is confined to a more technical use of the term; though even amongst computing professionals, some attach a much wider meaning to the word than others.
One possible definition is that a database is a collection of records stored in a computer in a systematic way, so that a computer program can consult it to answer questions. For better retrieval and sorting, each record is usually organized as a set of data elements (facts). The items retrieved in answer to queries become information that can be used to make decisions. The computer program used to manage and query a database is known as a database management system (DBMS). The properties and design of database systems are included in the study of information science.
The central concept of a database is that of a collection of records, or pieces of knowledge. Typically, for a given database, there is a structural description of the type of facts held in that database: this description is known as a schema. The schema describes the objects that are represented in the database, and the relationships among them. There are a number of different ways of organizing a schema, that is, of modeling the database structure: these are known as database models (or data models). The model in most common use today is the relational model, which in layman's terms represents all information in the form of multiple related tables each consisting of rows and columns (the true definition uses mathematical terminology). This model represents relationships by the use of values common to more than one table. Other models such as the hierarchical model and the network model use a more explicit representation of relationships.
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#NCFusion Task2: databases/Mercator_Map.kmmdatabase/unifiedindex.kda?version=61
ncfusion (nc fusion) Sat, 07 Nov 2009 01:59:59 -0000
#NCFusion Task2: databases/Mercator_Map.kmmdatabase/unifiedindex.kda?version=61
Hrm... I see one drawback to my awesome new laptop. It's a little slow in the disk-read department. Slow with databases, awesome with games.
kdnewton (kdnewton) Sat, 07 Nov 2009 01:43:30 -0000
Hrm... I see one drawback to my awesome new laptop. It's a little slow in the disk-read department. Slow with databases, awesome with games.
Ease with Expression Deed Databases | Top Free Essays http://bit.ly/3NHnK1
BuyingEssay (Buying Essay) Sat, 07 Nov 2009 01:39:25 -0000
Ease with Expression Deed Databases | Top Free Essays http://bit.ly/3NHnK1
#NCFusion Task1: databases/NCDA_Earth.kdatabase/qtpacket.kda?version=25
ncfusion (nc fusion) Sat, 07 Nov 2009 01:29:58 -0000
#NCFusion Task1: databases/NCDA_Earth.kdatabase/qtpacket.kda?version=25
Updating my databases
CaseyPorter (CaseyPorter) Sat, 07 Nov 2009 01:17:57 -0000
Updating my databases
RT @indicee @bitterer "Heard today from client: '...We have 2500 Excel databases.' JK--What in tarnation is an "Excel database"?
jameskobielus (jameskobielus) Sat, 07 Nov 2009 00:55:00 -0000
RT @indicee @bitterer "Heard today from client: '...We have 2500 Excel databases.' JK--What in tarnation is an "Excel database"?
Bulk Density Chart - Densities in standard and metric form, grouped by first letter of the product.
Dielectric Constant Reference Guide - Single page of several hundred chemicals, sorted by name, with associated dielectric constant.
EMSL Computational Results DataBase - A collection of information obtained from ab initio electronic structure calculations, as well as related experimental data and literature citations. Java database interface.
EMSL Gaussian Basis Sets - Extensible Computational Chemistry Environment Basis Set Database, Version 8/01/01, as developed and distributed by the Molecular Science Computing Facility, Environmental and Molecular Sciences Laboratory which is part of the Pacific Northwest Laboratory.
Fundamental Physical Constants from NIST - The values of the fundamental physical constants provided at this site are recommended for international use by CODATA and are the latest available.
Meta Description: [ The values of the fundamental physical constants provided at this site are recommended
for international use by CODATA and are the latest available. ]
GRI-Mech - site at Berkeley also has selected kinetic rate constants and parameters for reactions involving the species included in their database.
JPL Molecular Spectroscopy - Database which has an extensive library including programs for fitting spectra and spectral line files for a large number of molecules. Use requires knowledge of spectroscopy and quantum mechanics.
Materials Thermochemistry (Middlesex, UK) - Provides thermodynamic databases, data assessment, and consulting services to companies working with a variety of commercial and industrial materials. Information on training courses, models, downloads, example applications, and leasing databases.
Meta Description: [ Page not found ]
National Institute of Standards and Technology WebBook - Thermochemical data for over 6000 organic and small inorganic compounds. Reaction thermochemistry data for over 9000 reactions. IR spectra for over 8700 compounds. Mass spectra for over 12,000 compounds. UV/Vis spectra for over 400 compounds. Electronic and vibrational spectra for over 4000 compounds. Constants of diatomic molecules (spectroscopic data) for over 600 compounds. Ion energetics data for over 16,000 compounds. Thermophysical property data for 33 fluids.
Meta Description: [ NIST site provides chemical and physical property data on over 40,000 compounds. ]
Naval Research Laboratory Electronic Structure Calculations Database - Band structure, total energy, density of states, and derived quantities for most Periodic elements, hydrides, carbides, nitrides, and oxides.
NIST Physical Reference Data - Database holding information on fundamental physical constants, atomic spectra, molecular spectroscopic data, ionization data, X-Ray and Gamma-Ray data, radiation dosimetry data, nuclear physics data, and condensed matter physics data.
Meta Description: [ research data from NIST ]
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Pseudopotentials - Energy-consistent pseudopotentials of the Stuttgart/Bonn group (semi-local pseudopotentials adjusted to reproduce atomic valence-energy spectra) for every element in the periodical table. Provided by the University of Stuffgart.
Meta Description: [ Website der Universität Stuttgart ]
Quantum Chemistry Literature DataBase - A literature database on ab initio MO calculations published in major journals of Chemistry, Physics and Computer Science since 1978.
Quest Consultants - Source of thermodynamic data useful in handling phase transitions. The data are given as a function of temperature and pressure for single components and mixtures. Also links to Bubble Points, Dew Points, and Enthalpy-Pressure Diagram Pages.
Surface Tension Data - Surface tension values of some common test liquids for surface energy analysis.
Meta Description: [ Surface tension values of common test liquids ]
The Radiation Chemistry Data Center of the Notre Dame Radiation Laboratory - Chemical property data (such as reaction rate constants, and redox potentials,) historic bibliographic information from the RCDC bibliographic database, and recent papers in radiation chemistry and photochemistry. Also includes an on-line continuation of the Biweekly List of Papers in Radiation Chemistry and Photochemistry.
University of Alberta - Tables of chemical data for Fundamental Physical Constants, Relative Atomic Masses of the Chemical Elements, Molar Thermodynamic Properties of Pure Substances, Molar Thermodynamic Properties of Aqueous Solutes, Ionization Constants of Aqueous Monoprotic Acids, Ionization Constants of Aqueous Polyprotic Acids, Solubility Products of Slightly Soluble Salts, Stability Constants of Aqueous Complex Ions, and Aqueous Standard Reduction Potentials.
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