Changes

== Terminology ==

== Terminology ==

Data in a database is organized by means of a <i>key</i> which allows sorting the data for quick lookup and retrieval of the information.  For instance, a library's card catalog can be organized by title, or by author and title.  In the first case, the title is the key.  In the second case, the combined author and title are the key.  Each card represents a <i>record</i> of information, which contains <i>fields</i> of information (such as the publisher, copyright year, and a brief description, in addition to the author and title).  The size of the database is the number of records it contains.  This can be from 1 to billions of records.  Because a physical database can only be effectively sorted for one key, a card catalog had to be duplicated, with each duplicate being sorted differently (one by author name, one by title, etc).  In database terminology, each different sorted collection is called a [[database table|table]], and the collection of all related tables is collectively called a database.

Data in a database is organized by means of a <i>key</i> which allows sorting the data for quick lookup and retrieval of the information.  For instance, a library's card catalog can be organized by title, or by author and title.  In the first case, the title is the key.  In the second case, the combined author and title are the key.  Each card represents a <i>record</i> of information, which contains <i>fields</i> of information related to the key for that record (such as the publisher, copyright year, and a brief description, in addition to the author and title).  Because a physical database can only be effectively sorted for one key, a card catalog had to be duplicated, with each duplicate being sorted differently (one by author name, one by title, etc).  In database terminology, each different sorted collection is called a [[database table|table]], and the collection of all related tables is collectively called a database.

Implementation of a database in software provides several advantages over a physical database: 1) much smaller physical size, especially for large databases, 2) much faster lookup of information, 3) the ability to have multiple keys applied to the same data, rather than a separate table for the way each table is keyed, 4) the ability to quickly apply changes across multiple (or all) records.

The size of the database is the number of records it contains.  This can be from 1 to billions of records.  Implementation of a database in software provides several advantages over a physical database: 1) much smaller physical size, especially for large databases, 2) much faster lookup of information, 3) the ability to have multiple keys applied to the same data, rather than a separate table for the way each table is keyed, 4) the ability to quickly apply changes across multiple (or all) records.

== Organization ==

== Organization ==