Package org.h2.expression
Class ValueExpression
java.lang.Object
org.h2.expression.Expression
org.h2.expression.Operation0
org.h2.expression.ValueExpression
- Direct Known Subclasses:
TypedValueExpression
An expression representing a constant value.
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final ValueExpression
This special expression represents the default value.static final ValueExpression
The expression represents ValueBoolean.FALSE.static final ValueExpression
The expression represents ValueNull.INSTANCE.static final ValueExpression
The expression represents ValueBoolean.TRUE.(package private) final Value
The value.Fields inherited from class org.h2.expression.Expression
AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES
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 -
Method Summary
Modifier and TypeMethodDescriptionvoid
createIndexConditions
(SessionLocal session, TableFilter filter) Create index conditions if possible and attach them to the table filter.static ValueExpression
Create a new expression with the given value.static ValueExpression
getBoolean
(boolean value) Create a new expression with the given boolean value.static ValueExpression
getBoolean
(Value value) Create a new expression with the given boolean value.int
getCost()
Estimate the cost to process the expression.getNotIfPossible
(SessionLocal session) If it is possible, return the negated expression.getType()
Returns the data type.getUnenclosedSQL
(StringBuilder builder, int sqlFlags) Get the SQL statement of this expression.getValue
(SessionLocal session) Return the resulting value for the current row.boolean
Check if this expression will always return the same value.boolean
isEverything
(ExpressionVisitor visitor) Check if this expression and all sub-expressions can fulfill a criteria.boolean
Check if this expression will always return the NULL value.boolean
Is the value of a parameter set.Methods inherited from class org.h2.expression.Operation0
mapColumns, optimize, setEvaluatable, updateAggregate
Methods inherited from class org.h2.expression.Expression
addFilterConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getSubexpression, getSubexpressionCount, getTableAlias, getTableName, getWhenSQL, getWhenValue, isIdentity, isWhenConditionOperand, needParentheses, optimizeCondition, toString, writeExpressions, writeExpressions
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.h2.util.HasSQL
getTraceSQL
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Field Details
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NULL
The expression represents ValueNull.INSTANCE. -
DEFAULT
This special expression represents the default value. It is used for UPDATE statements of the form SET COLUMN = DEFAULT. The value is ValueNull.INSTANCE, but should never be accessed. -
TRUE
The expression represents ValueBoolean.TRUE. -
FALSE
The expression represents ValueBoolean.FALSE. -
value
The value.
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Constructor Details
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ValueExpression
ValueExpression(Value value)
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Method Details
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get
Create a new expression with the given value.- Parameters:
value
- the value- Returns:
- the expression
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getBoolean
Create a new expression with the given boolean value.- Parameters:
value
- the boolean value- Returns:
- the expression
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getBoolean
Create a new expression with the given boolean value.- Parameters:
value
- the boolean value- Returns:
- the expression
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getValue
Description copied from class:Expression
Return the resulting value for the current row.- Specified by:
getValue
in classExpression
- Parameters:
session
- the session- Returns:
- the result
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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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createIndexConditions
Description copied from class:Expression
Create index conditions if possible and attach them to the table filter.- Overrides:
createIndexConditions
in classExpression
- Parameters:
session
- the sessionfilter
- the table filter
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getNotIfPossible
Description copied from class:Expression
If it is possible, return the negated expression. This is used to optimize NOT expressions: NOT ID>10 can be converted to ID<=10. Returns null if negating is not possible.- Overrides:
getNotIfPossible
in classExpression
- Parameters:
session
- the session- Returns:
- the negated expression, or null
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isConstant
public boolean isConstant()Description copied from class:Expression
Check if this expression will always return the same value.- Overrides:
isConstant
in classExpression
- Returns:
- if the expression is constant
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isNullConstant
public boolean isNullConstant()Description copied from class:Expression
Check if this expression will always return the NULL value.- Overrides:
isNullConstant
in classExpression
- Returns:
- if the expression is constant NULL value
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isValueSet
public boolean isValueSet()Description copied from class:Expression
Is the value of a parameter set.- Overrides:
isValueSet
in classExpression
- Returns:
- true if set
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getUnenclosedSQL
Description copied from class:Expression
Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.- Specified by:
getUnenclosedSQL
in classExpression
- Parameters:
builder
- string buildersqlFlags
- formatting flags- Returns:
- the specified string builder
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isEverything
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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