<h3>RDBMS - Relational Database Management System</h3>

<p><em>Relational Model</em>: when there are relationships between items of
data such as products, customers and orders</p>

<p>A database contains two-dimensional <em>tables</em> which are similar in
concept to spreadsheets. Each table contains columns and rows like
a spreadsheet, but these are called <em>fields</em> and <em>records</em> in
database terminology</p>

<p>Data is stored in tables but is broken down into the most efficient form
such that there is no duplication. This process is called
<em>normalisation</em>.</p> 

<p>Fields have data types associated with them, such as numeric fields for
storing numbers or text fields for storing text.</p>

<p>Tables have <em>keys</em> to simplify searching. <em>Primary keys</em> are
used to make records in a table unique.</p>

<p><small>Shownotes by: Dave Morriss, 2015-08-14</small></p>
