title: What does this mean: unable to find an inherited method for function ‘A’ for signature ‘"B"’
body: <p>I am new to R and keep getting errors with the following message:</p>
  
  <blockquote>
    <p>unable to find an inherited method for function ‘A’ for signature ‘"B"’</p>
  </blockquote>
  
  <p>In most cases I've been able to solve my issues by finding alternate examples online, but I'd like to understand what the error message means so I can better understand how R works.</p>
  
  <p>For example, this code:</p>
  
  <pre><code>library("RSQLite")
  con = dbConnect(drv="SQLite", dbname="database.db")
  </code></pre>
  
  <p>Generates this warning:</p>
  
  <blockquote>
    <p>unable to find an inherited method for function ‘dbConnect’ for signature ‘"character"’</p>
  </blockquote>
  
  <p>And after fixing that error, this code:</p>
  
  <pre><code>dbClearResult(p1)
  </code></pre>
  
  <p>Produces this warning:</p>
  
  <blockquote>
    <p>unable to find an inherited method for function ‘dbClearResult’ for signature ‘"data.frame"’</p>
  </blockquote>
  
  <p>Can somebody please explain what this type of error message is trying to tell me?</p>
  
  <p>Specifically, the terms "interhited", "method", "function", and "signature" all seem related to concepts I understand from other languages, but the sentence structure of this error implies they have slightly different meanings in R.</p>