title: single quotes appear arround value after running copy in postgres 9.2
body: <p>I am new to postgres and I play around with data loading.
  Here is the table definition from postgres 9.2 spec:</p>
  
  <pre><code>CREATE TABLE weather (
      city varchar(80),
      temp_lo int, -- low temperature
      temp_hi int, -- high temperature
      prcp real, -- precipitation
      date date
   );
  </code></pre>
  
  <p>I prepared the following data file (weather.txt):</p>
  
  <pre><code>San Francisco   43  57  0.0 '1994-11-29'
  Hayward 54  37  0.0 '1994-11-29'
  </code></pre>
  
  <p>and ran the COPY command:</p>
  
  <pre><code>COPY weather FROM '~aviad/postsgres/playground/weather.txt';
  </code></pre>
  
  <p>now, when I run <code>select * from weather;</code> I see that single quotes appears around the city values.
  This does not happen when I run simple <code>INSERT</code> e.g:</p>
  
  <pre><code>INSERT INTO weather VALUES ('San Francisco', 46, 50, 0.25, '1994-11-27');
  </code></pre>
  
  <p>I wonder: </p>
  
  <ol>
  <li>what is the reason for wrapping text values by single quotes?</li>
  <li>What is the correct way to put the text data in the file used by
  <code>COPY</code> to avoid single quote wrapping?</li>
  </ol>