Package org.h2.expression
Class OperationN
- java.lang.Object
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- org.h2.expression.Expression
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- org.h2.expression.OperationN
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- All Implemented Interfaces:
ExpressionWithVariableParameters
,HasSQL
,Typed
- Direct Known Subclasses:
ConcatenationOperation
,FunctionN
,JsonConstructorFunction
,SearchedCase
public abstract class OperationN extends Expression implements ExpressionWithVariableParameters
Operation with many arguments.
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Field Summary
Fields Modifier and Type Field Description protected Expression[]
args
The array of arguments.protected int
argsCount
The number of arguments.protected TypeInfo
type
The type of the result.-
Fields inherited from class org.h2.expression.Expression
AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES
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Fields inherited from interface org.h2.util.HasSQL
ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS
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Constructor Summary
Constructors Modifier Constructor Description protected
OperationN(Expression[] args)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addParameter(Expression param)
Adds the parameter expression.void
doneWithParameters()
This method must be called after all the parameters have been set.int
getCost()
Estimate the cost to process the expression.Expression
getSubexpression(int index)
Returns subexpression with specified index.int
getSubexpressionCount()
Returns count of subexpressions.TypeInfo
getType()
Returns the data type.boolean
isEverything(ExpressionVisitor visitor)
Check if this expression and all sub-expressions can fulfill a criteria.void
mapColumns(ColumnResolver resolver, int level, int state)
Map the columns of the resolver to expression columns.protected boolean
optimizeArguments(SessionLocal session, boolean allConst)
Optimizes arguments.void
setEvaluatable(TableFilter tableFilter, boolean value)
Tell the expression columns whether the table filter can return values now.void
updateAggregate(SessionLocal session, int stage)
Update an aggregate value.-
Methods inherited from class org.h2.expression.Expression
addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getUnenclosedSQL, getValue, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, optimize, optimizeCondition, toString, writeExpressions, writeExpressions
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.h2.util.HasSQL
getTraceSQL
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Field Detail
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args
protected Expression[] args
The array of arguments.
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argsCount
protected int argsCount
The number of arguments.
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type
protected TypeInfo type
The type of the result.
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Constructor Detail
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OperationN
protected OperationN(Expression[] args)
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Method Detail
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addParameter
public void addParameter(Expression param)
Description copied from interface:ExpressionWithVariableParameters
Adds the parameter expression.- Specified by:
addParameter
in interfaceExpressionWithVariableParameters
- Parameters:
param
- the expression
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doneWithParameters
public void doneWithParameters() throws DbException
Description copied from interface:ExpressionWithVariableParameters
This method must be called after all the parameters have been set. It checks if the parameter count is correct when required by the implementation.- Specified by:
doneWithParameters
in interfaceExpressionWithVariableParameters
- Throws:
DbException
- if the parameter count is incorrect.
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getType
public TypeInfo getType()
Description copied from class:Expression
Returns the data type. The data type may be unknown before the optimization phase.- Specified by:
getType
in interfaceTyped
- Specified by:
getType
in classExpression
- Returns:
- the data type
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mapColumns
public void mapColumns(ColumnResolver resolver, int level, int state)
Description copied from class:Expression
Map the columns of the resolver to expression columns.- Specified by:
mapColumns
in classExpression
- Parameters:
resolver
- the column resolverlevel
- the subquery nesting levelstate
- current state for nesting checks, initial value isExpression.MAP_INITIAL
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optimizeArguments
protected boolean optimizeArguments(SessionLocal session, boolean allConst)
Optimizes arguments.- Parameters:
session
- the sessionallConst
- whether operation is deterministic- Returns:
- whether operation is deterministic and all arguments are constants
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setEvaluatable
public void setEvaluatable(TableFilter tableFilter, boolean value)
Description copied from class:Expression
Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.- Specified by:
setEvaluatable
in classExpression
- Parameters:
tableFilter
- the table filtervalue
- true if the table filter can return value
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updateAggregate
public void updateAggregate(SessionLocal session, int stage)
Description copied from class:Expression
Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.- Specified by:
updateAggregate
in classExpression
- Parameters:
session
- the sessionstage
- select stage
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isEverything
public boolean isEverything(ExpressionVisitor visitor)
Description copied from class:Expression
Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.- Specified by:
isEverything
in classExpression
- Parameters:
visitor
- the visitor- Returns:
- if the criteria can be fulfilled
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getCost
public int getCost()
Description copied from class:Expression
Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.- Specified by:
getCost
in classExpression
- Returns:
- the estimated cost
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getSubexpressionCount
public int getSubexpressionCount()
Description copied from class:Expression
Returns count of subexpressions.- Overrides:
getSubexpressionCount
in classExpression
- Returns:
- count of subexpressions
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getSubexpression
public Expression getSubexpression(int index)
Description copied from class:Expression
Returns subexpression with specified index.- Overrides:
getSubexpression
in classExpression
- Parameters:
index
- 0-based index- Returns:
- subexpression with specified index, may be null
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