class XxxUnknownValue : public XxxValueExpression

Represents column value expressions (like Emp

Inheritance:

Public Classes

class

UnknownValuePlan : public XxxValueExprPlan Execution plan for column expressions

Public Fields

int	CorrelationHeight 0 indicates uncorrelated
char	Name [XXX_ATTR_NAME_MAX] The name of the attribute
int	SrcAttrIndex The index of this attribute in the schema of that node
char	SrcChild The input index of the child in which this attribute is defined
char	XxxName [XXX_NODE_NAME_MAX] The name of the query node in which it is defined

Public Methods

virtual XxxBool	Equals (const XxxUnknownValue *Var) Check whether these two refer to the same unknown expr. Binquan
virtual XxxErrCode	GetDependencies (XxxBitMap& Dependendency, int CorrelationHt) Gets input stream dependencies (that were resolved in ResolveVars) Sets flags in the input argument DependsArray
virtual XxxBool	IsConstant () An unknown value is NOT a constant
virtual XxxBool	Match (const XxxExpression* OtherExpr, char *Env = NULL) Checks to see if the expression matches another expression
virtual XxxExpression*	Replicate () Provides a convenient way to copy arbitrary expressions
virtual XxxErrCode	ResolveVars (const XxxArgEnv* Env) to resolve correlation variables
virtual XxxErrCode	UpdateUnknowns (int ChildNumber, int OldAttrIndex, int NewAttrIndex, XxxBool &Appears) Substitutes NewAttrIndex for OldAttrIndex in the SrcAttrIndex field of XxxUnknownValues subexpressions with SrcChild == ChildNumber
	XxxUnknownValue (const char *VarName, const char *NodeName = NULL, const XxxBasicType Type = XXX_UNKNOWN, const int AttrIndex = -1, const int Child = -1) This constructor is called for variable names inside queries
	XxxUnknownValue (int Index, XxxBasicType Type, XxxADTMetaInfo *CatInfo = NULL) This constructor is called when a complete variable needs to be created in order to create an expression (possibly to set up a scan)
	XxxUnknownValue (int Index, const char *NodeName) This constructor is called for variables specified by positions inside queries
	XxxUnknownValue (const XxxUnknownValue& src) Copy constructor

Public

How many level above this did the correlation come from?

Inherited from XxxValueExpression:

Public Classes

enum ValExprTypeEnum

Public Fields

char* ExprName

Public Methods

virtual int Arity()

inline XxxValueExpression* ChildExpr(int i)

virtual XxxValueExprList* DirectSubexpressions()

virtual XxxADTMetaInfo* GenerateCatInfo()

virtual XxxErrCode Optimize(XxxValueExprPlan*& ExecPlan)

virtual void Print(ostream&)

virtual XxxBool ReferencesAggregate()

virtual XxxErrCode Replace(const XxxValueExpression *Target, const XxxValueExpression *Replacement)

virtual XxxErrCode Replace(const XxxUnknownValue *Target, const XxxValueExpression *Replacement)

XxxErrCode SetChild(int Index, XxxValueExpression* NewExp)

virtual XxxErrCode TypeCheck()

virtual XxxValueExprList* ValExprsReferenced()

Public

typedef enum ValExprTypeEnum ValExprType

enum ValExprTypeEnum

Protected Fields

int arity

XxxValueExpression** childExpr

class UnknownValuePlan: public XxxValueExprPlan

Execution plan for column expressions

char Name[XXX_ATTR_NAME_MAX]

The name of the attribute

char XxxName[XXX_NODE_NAME_MAX]

The name of the query node in which it is defined

char SrcChild

The input index of the child in which this attribute is defined

int SrcAttrIndex

The index of this attribute in the schema of that node

How many level above this did the correlation come from?

int CorrelationHeight

0 indicates uncorrelated

XxxUnknownValue(const char *VarName, const char *NodeName = NULL, const XxxBasicType Type = XXX_UNKNOWN, const int AttrIndex = -1, const int Child = -1)

This constructor is called for variable names inside queries. the constructor leaves the variable with incomplete info The info is filled in later in the context of the whole query.

XxxUnknownValue(int Index, const char *NodeName)

This constructor is called for variables specified by positions inside queries. The constructor leaves the variable with incomplete info (on the SrcChild). The info is filled in later in the context of the whole query.

XxxUnknownValue(int Index, XxxBasicType Type, XxxADTMetaInfo *CatInfo = NULL)

This constructor is called when a complete variable needs to be created in order to create an expression (possibly to set up a scan)

XxxUnknownValue(const XxxUnknownValue& src)

Copy constructor

virtual XxxExpression* Replicate()

Provides a convenient way to copy arbitrary expressions

virtual XxxBool Equals(const XxxUnknownValue *Var)

Check whether these two refer to the same unknown expr. Binquan

virtual XxxBool IsConstant()

An unknown value is NOT a constant

virtual XxxErrCode UpdateUnknowns(int ChildNumber, int OldAttrIndex, int NewAttrIndex, XxxBool &Appears)

Substitutes NewAttrIndex for OldAttrIndex in the SrcAttrIndex field of XxxUnknownValues subexpressions with SrcChild == ChildNumber

virtual XxxErrCode ResolveVars(const XxxArgEnv* Env)

to resolve correlation variables

virtual XxxBool Match(const XxxExpression* OtherExpr, char *Env = NULL)

Checks to see if the expression matches another expression

virtual XxxErrCode GetDependencies(XxxBitMap& Dependendency, int CorrelationHt)

Gets input stream dependencies (that were resolved in ResolveVars) Sets flags in the input argument DependsArray. The array must be initialized to be all false. The size of the array is 1+ the actual number of input streams. The extra entry stands for the run-time Env

alphabetic index hierarchy of classes

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