public NestedLoopJoinOperation(LogicalElement logicalElement, ReadLogicalElement left, ReadLogicalElement right, AttributeDefinition leftJoinColumn, AttributeDefinition rightJoinColumn)
     : base(logicalElement)
 {
     LeftLogical      = left;
     RightLogical     = right;
     _leftJoinColumn  = leftJoinColumn;
     _rightJoinColumn = rightJoinColumn;
 }
 public ReadLogicalElement(ReadLogicalElement leftChild, ReadLogicalElement rightChild) : base(leftChild, rightChild)
 {
 }
 public ReadLogicalElement(ReadLogicalElement child) : base(child)
 {
 }