System.Data.ConstraintCollection.Add C# (CSharp) Method

        internal void Add(Constraint constraint, bool addUniqueWhenAddingForeign)
        {
            if (constraint == null)
            {
                throw ExceptionBuilder.ArgumentNull(nameof(constraint));
            }

            // It is an error if we find an equivalent constraint already in collection
            if (FindConstraint(constraint) != null)
            {
                throw ExceptionBuilder.DuplicateConstraint(FindConstraint(constraint).ConstraintName);
            }

            if (1 < _table.NestedParentRelations.Length)
            {
                if (!AutoGenerated(constraint))
                {
                    throw ExceptionBuilder.CantAddConstraintToMultipleNestedTable(_table.TableName);
                }
            }

            if (constraint is UniqueConstraint)
            {
                if (((UniqueConstraint)constraint)._bPrimaryKey)
                {
                    if (Table._primaryKey != null)
                    {
                        throw ExceptionBuilder.AddPrimaryKeyConstraint();
                    }
                }
                AddUniqueConstraint((UniqueConstraint)constraint);
            }
            else if (constraint is ForeignKeyConstraint)
            {
                ForeignKeyConstraint fk = (ForeignKeyConstraint)constraint;
                if (addUniqueWhenAddingForeign)
                {
                    UniqueConstraint key = fk.RelatedTable.Constraints.FindKeyConstraint(fk.RelatedColumnsReference);
                    if (key == null)
                    {
                        if (constraint.ConstraintName.Length == 0)
                            constraint.ConstraintName = AssignName();
                        else
                            RegisterName(constraint.ConstraintName);

                        key = new UniqueConstraint(fk.RelatedColumnsReference);
                        fk.RelatedTable.Constraints.Add(key);
                    }
                }
                AddForeignKeyConstraint((ForeignKeyConstraint)constraint);
            }
            BaseAdd(constraint);
            ArrayAdd(constraint);
            OnCollectionChanged(new CollectionChangeEventArgs(CollectionChangeAction.Add, constraint));

            if (constraint is UniqueConstraint)
            {
                if (((UniqueConstraint)constraint)._bPrimaryKey)
                {
                    Table.PrimaryKey = ((UniqueConstraint)constraint).ColumnsReference;
                }
            }
        }