System.Data.UniqueConstraint.ConstraintIndexInitialize C# (CSharp) Method

        internal void ConstraintIndexInitialize()
        {
            if (null == _constraintIndex)
            {
                _constraintIndex = _key.GetSortIndex();
                _constraintIndex.AddRef();
            }

            AssertConstraintAndKeyIndexes();
        }

 private void AddUniqueConstraint(UniqueConstraint constraint)
 {
     DataColumn[] columnsReference = constraint.ColumnsReference;
     for (int i = 0; i < columnsReference.Length; i++)
     {
         if (columnsReference[i].Table != this.table)
         {
             throw ExceptionBuilder.ConstraintForeignTable();
         }
     }
     constraint.ConstraintIndexInitialize();
     if (!constraint.CanEnableConstraint())
     {
         constraint.ConstraintIndexClear();
         throw ExceptionBuilder.UniqueConstraintViolation();
     }
 }