title: relationship type,degree, cardinality, optionality terms confusion
body: <p>I currently studying database i've seen <strong><em>degree</em></strong> and <strong><em>cardinality</em></strong> uses as same term, or in some other degree is defined as no. of entities involved in a relationship and further catogories as unary, binary and trenary. </p>
  
  <p>Some placed degree is defined as The degree of a relationship type concerns the number of entities within each entity type that can be linked by a given relationship type.</p>
  
  <p>Cardinality is minimum and maximun number of entity occurrence associated with one occurrence of
  the related entity</p>
  
  <p>cardinality types as <code>1 to 1</code> , <code>1 to many</code> , <code>many to many</code>. or min and max cardinality.</p>
  
  <p>Min degree is optionality and maximum degree is cardinalty.</p>
  
  <p>what is the difference between degree and cardinaltiy ?</p>
  
  <p>In another context cardinality is a number of rows in table and degree is a number of columns.</p>
  
  <p>So what i'm i suppose to write if question is asked "Define cardinality ?".</p>
  
  <p>Can somebody explain ? </p>