Field Detail

• firstOr

  private boolean firstOr

Constructor Detail

• OrNode

  OrNode​(ValueNode leftOperand,
         ValueNode rightOperand,
         ContextManager cm)

  Constructor for an OrNode

  Parameters:

  leftOperand - The left operand of the OR

  rightOperand - The right operand of the OR

  cm - The context manager

Method Detail

• setFirstOr

  void setFirstOr()

  Mark this OrNode as the 1st OR in the OR chain. We will consider converting the chain to an IN list during preprocess() if all entries are of the form: ColumnReference = expression

• bindExpression

  ValueNode bindExpression​(FromList fromList,
                           SubqueryList subqueryList,
                           java.util.List<AggregateNode> aggregates)
                    throws StandardException

  Bind this logical operator. All that has to be done for binding a logical operator is to bind the operands, check that both operands are BooleanDataValue, and set the result type to BooleanDataValue.

  Overrides:

  bindExpression in class BinaryLogicalOperatorNode

  Parameters:

  fromList - The query's FROM list

  subqueryList - The subquery list being built as we find SubqueryNodes

  aggregates - The aggregate list being built as we find AggregateNodes

  Returns:

  The new top of the expression tree.

  Throws:

  StandardException - Thrown on error

• preprocess

  ValueNode preprocess​(int numTables,
                       FromList outerFromList,
                       SubqueryList outerSubqueryList,
                       PredicateList outerPredicateList)
                throws StandardException

  Preprocess an expression tree. We do a number of transformations here (including subqueries, IN lists, LIKE and BETWEEN) plus subquery flattening. NOTE: This is done before the outer ResultSetNode is preprocessed.

  Overrides:

  preprocess in class BinaryOperatorNode

  Parameters:

  numTables - Number of tables in the DML Statement

  outerFromList - FromList from outer query block

  outerSubqueryList - SubqueryList from outer query block

  outerPredicateList - PredicateList from outer query block

  Returns:

  The modified expression

  Throws:

  StandardException - Thrown on error

• eliminateNots

  ValueNode eliminateNots​(boolean underNotNode)
                   throws StandardException

  Eliminate NotNodes in the current query block. We traverse the tree, inverting ANDs and ORs and eliminating NOTs as we go. We stop at ComparisonOperators and boolean expressions. We invert ComparisonOperators and replace boolean expressions with boolean expression = false. NOTE: Since we do not recurse under ComparisonOperators, there still could be NotNodes left in the tree.

  Overrides:

  eliminateNots in class ValueNode

  Parameters:

  underNotNode - Whether or not we are under a NotNode.

  Returns:

  The modified expression

  Throws:

  StandardException - Thrown on error

• changeToCNF

  ValueNode changeToCNF​(boolean underTopAndNode)
                 throws StandardException

  Finish putting an expression into conjunctive normal form. An expression tree in conjunctive normal form meets the following criteria: o If the expression tree is not null, the top level will be a chain of AndNodes terminating in a true BooleanConstantNode. o The left child of an AndNode will never be an AndNode. o Any right-linked chain that includes an AndNode will be entirely composed of AndNodes terminated by a true BooleanConstantNode. o The left child of an OrNode will never be an OrNode. o Any right-linked chain that includes an OrNode will be entirely composed of OrNodes terminated by a false BooleanConstantNode. o ValueNodes other than AndNodes and OrNodes are considered leaf nodes for purposes of expression normalization. In other words, we won't do any normalization under those nodes. In addition, we track whether or not we are under a top level AndNode. SubqueryNodes need to know this for subquery flattening.

  Overrides:

  changeToCNF in class ValueNode

  Parameters:

  underTopAndNode - Whether or not we are under a top level AndNode.

  Returns:

  The modified expression

  Throws:

  StandardException - Thrown on error

• verifyChangeToCNF

  boolean verifyChangeToCNF()

  Verify that changeToCNF() did its job correctly. Verify that: o AndNode - rightOperand is not instanceof OrNode leftOperand is not instanceof AndNode o OrNode - rightOperand is not instanceof AndNode leftOperand is not instanceof OrNode

  Overrides:

  verifyChangeToCNF in class ValueNode

  Returns:

  Boolean which reflects validity of the tree.

• postBindFixup

  void postBindFixup()
              throws StandardException

  Do bind() by hand for an AndNode that was generated after bind(), eg by putAndsOnTop(). (Set the data type and nullability info.)

  Throws:

  StandardException - Thrown on error