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Glossary of terms:

     A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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Attributes Attributes are the record elements contained within tables e.g. a customer table would contain information such as name, address etc. They are technically known as "attributes" of the entity "customer".
Access Microsoft Access is one of many databases that offers a flexible environment for developers and users.  It makes use of the familiar Microsoft Office interface and allows for integration with larger-scale enterprise databases such as Microsoft's SQL Server and Oracle.  Due to the familiar Microsoft format, this is a good starting point when learning about database creation
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Boyce-Codd Normal Form A relation is in Boyce-Codd Normal Form (BCNF) if every determinant is a candidate key.
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Candidate Key A candidate key is a combination of attributes which allows the identification of a database record.
Column The tables within a database are made up of individual columns relating to the attributes of the object.  
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Data Data consists of a series of unorganised facts or statements that have been collected, stored, processed and/or manipulated.   
Database A database is a collection of information organised into inter-related tables of data, to allow users to reach the required information with ease
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Entity The word ‘entity’ as it relates to databases can simply be defined as the general name for the information that is to be stored within a single table e.g. a "customer" table.
Entity-Relationship Diagram (ERD) An ERD is essentially a graphical representation of the database structure.
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First Normal Form To be in First Normal Form, each field in a table contains different information and should therefore contain no repeating attributes. For example, in an employee list, each table would contain only one birthdate field.
Foreign Key A Foreign key forms the basis of a 1:M relationship between two tables. The Foreign key can be found within the "M" table, and maps to the Primary key found in the "1" table.
Flat File Flat files are data files that contain records but do not have any structured relationships.  Additional knowledge is required to interpret these files such as the file format properties. 
Form A database form can be used to facilitate database data entry and/or retrieval operations and is usually developed for a user without any specific database skills.
Fourth Normal Form To be in Fourth Normal Form, a relation must first be in Boyce-Codd Normal Form.  Additionally, a given relation may not contain more than one multivalued attribute.
Functional Dependency A functional dependency occurs when one attribute determines another attribute.
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Hierarchical database A kind of database management system that links records together like a family tree such that each record type has only one owner, e.g. an order is owned by only one customer. Hierarchical structures were widely used in the first mainframe database management systems. However, due to their restrictions, they often cannot be used to relate structures that exist in the real world.
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Incremental Updates Consist of records that are to be "merged" with the data already in a database. When a database integrates data into its own, it checks for unique record ID's. e.g. if a book with an ID already in the database is found, the database overwrites the old record with the new.
Index An Index is a database feature used for locating data quickly within a table. For example, Employee information may be stored in a Human Resource department's Employee table. To search the table for Employees by last name may result in a slow query response. Defining an "Index" on the table consisting of the last name attribute would speed up these queries.  An index is a link between one table and another, it allows for rapid access to the rows of a table based on the values of one or more columns in another table.
Information Data that has been processed in such a way that it can increase the knowledge of the person who receives it. Information is the output, or finished goods, of information systems. Information is also what individuals start with before it is fed into a Data Capture transaction processing system.
Input Mask An input mask helps to control the values that are entered into a field and might include dashes, spaces, or parentheses.  Input masks may be automatically applied to certain fields, such as phone numbers or zip codes.
Instance A technical term used to refer to a database in a way that includes all of its technical components (the disk files that hold the tables, the part of the computer memory allocated for the database and the software that is necessary to manage the database).
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Join Join operators compare two or more tables (or views) by specifying a column from each, comparing the values in those columns row by row, and concatenating rows in which the comparison is true.
Journal File A file that contains update activity for rollback and data recovery purposes. Examples of update activity are commit checkpoints, as well as before and after operational database images. A journal file may be used to construct snapshot information for the data warehouse.
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Key A database "Key " is an attribute used to sort and/or identify data contained in a table. Each table has a primary key which uniquely identifies records. Foriegn keys are utilized to cross-reference data between relational tables.
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Local Access Database (LAD) A database that serves individual systems and workgroups as the end point for shared data distribution. LADs are the retail outlets of the data warehouse network. They provide direct access to the data requested by specific systems or desktop query services.
Logical Data Model Actual implementation of a conceptual module in a database. It may take multiple logical data models to implement one conceptual data model.
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Mainframe A term originally referring to the cabinet containing the central processor unit or "main frame" of a room-filling “batch” processing machine.  After the emergence of smaller "minicomputer" designs in the early 1970s, the traditional “big iron” machines were described as "mainframe computers" and eventually just as mainframes.
Many-to-Many (M:M) A many-to-many relationship signifies that many instances of a given entity relate to many instances of another entity.
Master Table The relationship between tables is like a ‘master and slave’ relationship. The master controls the detail.
Metadata Data that describes the data in a database.  It includes the names of tables, columns and indexes, how the data items are used, business definitions, relationships between data, how the data has been processed and information about how current the data is.
Multi-dimensional Database (MDBS and MDBMS or MDDs) A powerful database that lets users analyse large amounts of data. An MDBS captures and presents data as arrays that can be arranged in multiple dimensions.

Multiple table queries

Multiple table queries are queries that use more than one table.
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In relational database design, the process of Normalisation is organising table data to minimise duplication.

"Normalisation involves dividing a database into 2 or more tables and defining relationships between the tables. The objective of normalisation is to isolate data so that additions, deletions and modifications of data fields can be made in just one table and then propagated (spread) through the rest of the database using pre-defined relationships”

Normal Form A Relational Database can provide control over how data is used and how the data is stored and shared with other users. The database stores information in a series of linked tables, designed in a way that minimises the number of repeating data items. Such systems provide facilities that make it easy to index and manage large amounts of data in many tables thereby permitting efficient data storage.

Normal Forms are the series of logical steps applied to database data and tables

Navigation Bar In FrontPage, a collection of graphical or textual buttons containing hyperlinks to pages that are part of the same web structure
Network Model The objective of a network model is to separate data structure from physical storage, eliminate unnecessary duplication of data with associated errors and costs. It uses the concept of M:N linkages or relationships
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One-to-One (1:1) A one-to-one relationship signifies that each instance of a given entity relates to exactly one instance of another entity.
One-to-Many (1:M) A one-to-many relationship signifies that each instance of a given entity relates to one or more instances of another entity.
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Picture A graphics file that can be inserted on a Web page and displayed in a Web browser. FrontPage for example lets you import graphics in the following formats: GIF, JPEG (standard and progressive), BMP (Windows and OS/2), TIFF, TGA, RAS, EPS, PCX, WMF, and PNG. Imported graphics are converted to GIF format (for graphics containing up to 256 colors) or JPEG format (for graphics containing over 256 colors) when the page is saved to the current web. Also called image.
PL/SQL Was introduced, as a procedural extension to SQL by the Oracle Corporation with the release of Oracle 6. Its main functions were to allow for the provision of a procedural language available to Oracle programs without the need to pass control back to the user after the execution of every SQL statement (one of the weaknesses of SQL being that the user can only execute a single statement at one time)
Plug In One of a set of software modules that integrate into Web browsers to offer a range of interactive and multimedia capabilities
Primary Key

Unique Identifier for the primary COLUMN in the table - and the data item that uniquely identifies each record.

•     Use integers to save memory & increase speed

•     Can be “composite” or “compound” Key

 (means made of multiple parts [or multiple keys])

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Referential Integrity

Referential Integrity is a feature provided by Relational Database Management System (RDBMS) that prevents users or applications from entering inconsistent data. Most RDBMS have various referential integrity rules that are automatically applied when you create a relationship between two tables.

Relational Therefore relational database systems can use multiple tables to store information, and each table can have a different record format
Relationship The various relationships both between the data items forming the various entities and the relationship between entities themselves.
Rollback & Commit A standard mechanism for ensuring completion of a set of transactions involves; commit (like a Save) and rollback (rolls the data back to the previous, ‘good’ save).
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Script A type of computer code that can be directly executed by a program that understands the language in which the script is written. Scripts do not need to be compiled to be run.
Second Normal Form A record is in Second Normal Form provided it satisfies the condition for 1NF and also all non-key data items are fully functionally dependant on the primary key.
Server A computer that offers services on a network. On the World Wide Web, a server is a computer that runs the Web server software that responds to HTTP protocol requests. Also called host.
SQL Structured Query Language - is a standard relational database language, it is used by the majority of systems now to retrieve and update data held on a database.
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Third Normal Form A record is in Third Normal Form provided it satisfies the condition for 2NF and also no non-key data item is functionally dependant on any other non-key data item.
Type this is a set of pre-defined characteristics, which control the behaviour of data. Database data of type ‘currency’ will have a currency symbol prefix £ or $ and can only be in a numeric format. Attempting to enter a letter in a database field of type currency will generate an validation error.
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Uniform Resource Locator (URL)

is a fancy name for address. The URL contains information about where the file is to be found and what actions a browser should take with the file.

URL’s can be either ‘relative’ or ‘absolute’.

Relative addressing means the file can be found locally within a web site or hard disk drive e.g. normalise/1nf.htm - 1nf.htm can be found within the folder called normalise.

Absolute web addressing means the address is global, that is it has; http:// www.norm.com before the norm/1nf.htm – think of an absolute address; like a postal address, without all the parts of the address, mail cannot be delivered to the correct destination.
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a name for the method of ensuring data is entered in the correct format, length or case.

If a validation rule for a database field is contravened, then an error message should be displayed.  

Verification in a database; verification rules are used to intercept typographic errors or spelling errors.
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is short for World Wide Web Consortium. The Consortium www.w3c.org is solely concerned with web universality. It promotes the use of common formats, increasing browser compatibility and encourages web designers to adhere to a series of standards. Their aim is to improve the web for all.

(Try ‘file/view source’ on this page; to see the HTML source code; look at the top for W3C references!)

World Wide Web technically a sub-set of the Internet – the web comprises of a series of hyperlinked files and documents, stored on servers. Commonly used to describe any computer resource, that can be reached or accessed using a web browser.
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Extensible Markup Language: an newer improved, but more complex version of HTML.

Its purpose is to disentangle all the HTML tags and formatting commands from within web pages.

This will allow – in the future – significant improvements in Internet search engine performance, because all the formatting commands will be ‘tagged’ as ‘code’ and thus ignored in web searches.

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