code: function (name) {
              var args = argsToArray(arguments).slice(1);
              var block = isFunction(args[args.length - 1]) ? args[args.length - 1]() : null;
              this.operations.push({op:"addConstraint", name:name, type:"check", check:block || args});
          }
docs: Add a constraint with the given name and args to the DDL for the table.
  See {@link patio.SchemaGenerator#constraint}.
  
  @example
  var sql = patio.sql;
  DB.alterTable("test", function(){
  this.addConstraint("valid_name", sql.name.like('A%'));
  //=>ADD CONSTRAINT valid_name CHECK (name LIKE 'A%')
  });