title: How to use wild card character * in dynamodb query operation?
body: <p>I am using aws-ruby-sdk for accessing dynamodb. I want to use query operation and get all items. So I am using wildcard character * in expression_attribute_values. It doesn't work. However, if I specify a specific value, it works.</p>
  
  <p>How do I use * ? Below is my code to query dynamodb:</p>
  
  <pre><code>db_client.query({
          table_name: "my_table_name",
          key_condition_expression: "#idtype = :idType",
          expression_attribute_names: {
               "#idtype" =&gt; "IdType"
           },
          expression_attribute_values: {
               ":idType" =&gt; "*",
          },
      })
  </code></pre>
  
  <p>Also I am specifying * because I want all values. End result I want is only unique values in the primary key IdType but there seem to be no way to have unique constraint in dynamodb (not that I know of) so I am fetching all values and will have unique values from the result using my own code.</p>
  
  <p>Any help would be appreciated.</p>
  
  <p>PS: Primary Partition Key - IdType is a String</p>