It is likely that your application is going to have tables that
    represent users.  The next stage of your implementation is going
    to be to link your users with Veil2's
    accessors.
  
    Look for STEP 4 in the file
    veil2_demo--<version>.sql.
  
    You will need to create links between each of your user tables
    and the veil2.accessors
    table.
  
    You will create foreign-key constraints back to those tables,
    and create triggers to keep the mapping and
    accessors tables in step with changes in your
    users tables.
  
      You will create a mapping table, ideally in the
      veil2 schema, that will consist of foreign key
      references to both the veil2.accessors table
      and whatever tables from your database that need you need to link
      to.  You will also create indexes for performance, and
      foreign-key references back to your users tables.
    
      Note that as a simplification, the demo chooses to use the
      accessor_id from the
      accessors table as the primary key for its
      parties table.
    
      Create copies of the existing user records in
      veil2.accessors.  Note that you will need to
      create records in both the
      veil2.accessors and the new mapping table for
      each users record.  See the demo.
    
      What we need to do is populate the 
      veil2.authentication_details
      table from the authentication details (passwords) in your source
      database.  Depending on how secure your existing system is, this
      may prove to be difficult.  For instance if you use a simple
      salted hash to store your passwords, you will be unable to
      generate a bcrypt password from it.  In this case you have
      2 basic choices:
      
	    implement your current password management scheme in
	    Veil2;
	  
In this case you will be able to simply copy the current hashed passwords.
implement a password migration scheme.
You will create bcrypt tokens from the users' passwords, as they enter them into your system.
      When new users are created, updated or deleted in your users
      table, we need the veil2.accessors records to
      reflect this.  Triggers on your users tables must be created to
      achieve this.  
    
      Ideally, on an ongoing basis, all authentication details will be
      kept solely in veil2.authentication_details
      and use of the original users tables for this will be
      deprecated.  Until this can be completed though, you may still
      be allowing passwords etc to be created in your original users
      tables.
    
      To ensure that password changes are propagated to
      Veil2, triggers should be placed on the
      source tables which will cause the appropriate modifications to
      be made to veil2.authentication_details.
      Again, examples can be found in the demo code.