title: How do I update multiple records in Oracle?
body: <p>I have millions of records in a table and I need to update particular records which have wrong values. How do I do it?</p>
  
  <p>Example:</p>
  
  <pre><code>Si Item_Id
  1  T21547856
  2  T45200254
  3  T54785000
  </code></pre>
  
  <p>Need to update like:</p>
  
  <pre><code>T21547856 = CS2541
  T54785000 = CS5475
  </code></pre>
  
  <p>This is just an example. I have millions of records and need to update more than half a million.</p>