title: How to restrict duplicate record to insert into table in snowflake
body: <p>I have created below table with primary key in snowflake and whenever i am trying to insert data into this table, it's allow duplicate records also.
  How to restrict duplicate id ?</p>
  
  <pre><code>create table tab11(id int primary key not null,grade varchar(10));
  
  insert into tab11 values(1,'A');
  insert into tab11 values(1,'B');
  
  select * from tab11;
  </code></pre>
  
  <p>Output: Inserted duplicate records.</p>
  
  <pre><code>ID  GRADE
  1   A
  1   B
  </code></pre>