title: How to add primary key constraint on oracle?
body: <pre><code>CREATE TABLE buses(Bus_no NUMBER(11) NOT NULL ,Bus_name Varchar2(20),Type VARCHAR2(20),Total_seats Number(11),Avail_seats Number(11));
  ALTER TABLE buses
  ADD CONSTRAINT PK_BUSES UNIQUE(Bus_no);
  </code></pre>
  
  <p>This is the table I need to create .. and this should be the output:</p>
  
  <pre><code>Name                       Null?    Type
   ----------------------------------------- -------- ----------------------------
   BUS_NO                    NOT NULL NUMBER(11)
   BUS_NAME                       VARCHAR2(20)
   TYPE                           VARCHAR2(20)
   TOTAL_SEATS                        NUMBER(11)
   AVAIL_SEATS                        NUMBER(11)
  
  CONSTRAINT_NAME
  ------------------------------
  PK_BUSES
  </code></pre>
  
  <p>However I am getting this extra line SYS-C00403053 along with my output table,please help to remove this.</p>
  
  <pre><code>CONSTRAINT_NAME
  ------------------------------
  SYS_C00403053
  PK_BUSES
  </code></pre>