title: Why are relational databases unsuitable for unstructured data?
body: <p>I've been researching NoSQL databases, and a common theme that comes up is that relational databases are unsuitable for storing unstructured data. For example:</p>
  
  <blockquote>
    <p>Unfortunately, the rigidly defined, schema-based approach used by relational databases... is a poor fit for unstructured and semi-structured data
    <a href="http://www.couchbase.com/why-nosql/nosql-database" rel="noreferrer">[source]</a></p>
  </blockquote>
  
  <p>I'm having a hard time understanding why this is. For example, if I wanted to store an image or some raw text in a relational database, could I not just store it as a text type (e.g. in a single column table or a key-value table)?</p>