pack-priv Class UnaryOperatorNode

Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.acceptChildren.

Accept the visitor for all visitable children of this node.

Parameters

v:Visitor

the visitor

Annotations

@Override

Exceptions

StandardException:

on error

Add some additional arguments to our method call for XML related operations like XMLPARSE and XMLSERIALIZE.

Parameters

acb:ExpressionClassBuilder

the builder for the class in which the method lives

mb:MethodBuilder

The MethodBuilder that will make the call.

resultField:LocalField

the field that contains the previous result

Returns:int

Number of parameters added.

Overrides org.apache.derby.impl.sql.compile.ValueNode.bindExpression.

Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. This method is the implementation for XMLPARSE and XMLSERIALIZE. Sub-classes need to implement their own bindExpression() method for their own specific rules.

Parameters

fromList:FromList

The FROM list for the query this expression is in, for binding columns.

subqueryList:SubqueryList

The subquery list being built as we find SubqueryNodes

aggregates:List<AggregateNode>

The aggregate list being built as we find AggregateNodes

Returns:ValueNode

The new top of the expression tree.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

By default unary operators don't accept ? parameters as operands. This can be over-ridden for particular unary operators. We throw an exception if the parameter doesn't have a datatype assigned to it yet.

Exceptions

StandardException:

Thrown if ? parameter doesn't have a type bound to it yet. ? parameter where it isn't allowed.

Overrides org.apache.derby.impl.sql.compile.ValueNode.categorize.

Categorize this predicate. Initially, this means building a bit map of the referenced tables for each predicate. If the source of this ColumnReference (at the next underlying level) is not a ColumnReference or a VirtualColumnNode then this predicate will not be pushed down. For example, in: select * from (select 1 from s) a (x) where x = 1 we will not push down x = 1.

Parameters

referencedTabs:JBitSet

JBitSet with bit map of referenced FromTables

simplePredsOnly:boolean

Whether or not to consider method calls, field references and conditional nodes when building bit map

Returns:boolean

boolean Whether or not source.expression is a ColumnReference or a VirtualColumnNode.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.ValueNode.constantExpression.

Doc from org.apache.derby.impl.sql.compile.ValueNode.constantExpression.

Return whether or not this expression tree represents a constant value. In this case, "constant" means that it will always evaluate to the same thing, even if it includes columns. A column is constant if it is compared to a constant expression.

Returns:boolean

True means this expression tree represents a constant value.

Annotations

@Override

See Also

ValueNode#constantExpression

Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression.

Do code generation for this unary operator.

Parameters

acb:ExpressionClassBuilder

The ExpressionClassBuilder for the class we're generating

mb:MethodBuilder

The method the expression will go into

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Get the operand of this unary operator.

Returns:ValueNode

The operand of this unary operator.

Get the operator of this unary operator.

Returns:String

The operator of this unary operator.

Get the parameter operand of this unary operator. For the example below, for abs unary operator node, we want to get ? select * from t1 where -? = max_cni(abs(-?), sqrt(+?)) This gets called when ParameterNode is needed to get parameter specific information like getDefaultValue(), getParameterNumber() etc

Returns:ParameterNode

The parameter operand of this unary operator else null.

Determine the type the binary method is called on. By default, based on the receiver. Override in nodes that use methods on super-interfaces of the receiver's interface, such as comparisons.

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.ValueNode.isConstantExpression.

Return whether or not this expression tree represents a constant expression.

Returns:boolean

Whether or not this expression tree represents a constant expression.

Annotations

@Override

Implements abstract org.apache.derby.impl.sql.compile.ValueNode.isEquivalent.

Doc from org.apache.derby.impl.sql.compile.ValueNode.isEquivalent.

Tests if this node is equivalent to the specified ValueNode. Two ValueNodes are considered equivalent if they will evaluate to the same value during query execution.

This method provides basic expression matching facility for the derived class of ValueNode and it is used by the language layer to compare the node structural form of the two expressions for equivalence at bind phase.

Note that it is not comparing the actual row values at runtime to produce a result; hence, when comparing SQL NULLs, they are considered to be equivalent and not unknown.

One usage case of this method in this context is to compare the select column expression against the group by expression to check if they are equivalent. e.g.:

SELECT c1+c2 FROM t1 GROUP BY c1+c2

In general, node equivalence is determined by the derived class of ValueNode. But they generally abide to the rules below:

• The two ValueNodes must be of the same node type to be considered equivalent. e.g.: CastNode vs. CastNode - equivalent (if their args also match), ColumnReference vs CastNode - not equivalent.
• If node P contains other ValueNode(s) and so on, those node(s) must also be of the same node type to be considered equivalent.
• If node P takes a parameter list, then the number of arguments and its arguments for the two nodes must also match to be considered equivalent. e.g.: CAST(c1 as INTEGER) vs CAST(c1 as SMALLINT), they are not equivalent.
• When comparing SQL NULLs in this context, they are considered to be equivalent.
• If this does not apply or it is determined that the two nodes are not equivalent then the derived class of this method should return false; otherwise, return true.

Parameters

o:ValueNode

the node to compare this ValueNode against.

Returns:boolean

true if the two nodes are equivalent, false otherwise.

Exceptions

StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.isSameNodeKind.

Doc from org.apache.derby.impl.sql.compile.ValueNode.isSameNodeKind.

Some node classes represent several logical node types (to reduce footprint), which we call kinds. This means that implementations of isEquivalent cannot always just use instanceof to check if the other node represents the same kind. Hence this method needs to be overridden by all node classes that represent several kinds. This default implementation does not look at kinds. It is only called from implementations of isEquivalent.

Parameters

o:ValueNode

The other value node whose kind we want to compare with.

Returns:boolean

true if this and o represent the same logical node type, i.e. kind.

Annotations

@Override

Overrides org.apache.derby.impl.sql.compile.ValueNode.preprocess.

Preprocess an expression tree. We do a number of transformations here (including subqueries, IN lists, LIKE and BETWEEN) plus subquery flattening.

Parameters

numTables:int

Number of tables in the DML Statement

outerFromList:FromList

FromList from outer query block

outerSubqueryList:SubqueryList

SubqueryList from outer query block

outerPredicateList:PredicateList

PredicateList from outer query block

Returns:ValueNode

The modified expression

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.printSubNodes.

Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.

Parameters

depth:int

The depth of this node in the tree

Annotations

@Override

Overrides org.apache.derby.impl.sql.compile.ValueNode.remapColumnReferencesToExpressions.

Remap all ColumnReferences in this tree to be clones of the underlying expression.

Returns:ValueNode

ValueNode The remapped expression tree.

Annotations

@Override

Exceptions

StandardException:

Thrown on error

Set the methodName.

Parameters

methodName:String

The methodName.

Set the operator.

Parameters

operator:String

The operator.