ASA SQL User's Guide
  Monitoring and Improving Performance
    Top performance tips

Use AUTOINCREMENT to create primary keys

Primary key values must be unique. Although there are a variety of ways to create unique values for primary keys, the most efficient method is setting the default column value to be AUTOINCREMENT ON. You can use this default for any column in which you want to maintain unique values. Using the AUTOINCREMENT feature to generate primary key values is faster than other methods because the value is generated by the server.