Package org.h2.expression.condition
Class ConditionAndOrN
java.lang.Object
org.h2.expression.Expression
org.h2.expression.condition.Condition
org.h2.expression.condition.ConditionAndOrN
An 'and' or 'or' condition as in WHERE ID=1 AND NAME=? with N operands.
Mostly useful for optimisation and preventing stack overflow where generated
SQL has tons of conditions.
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate List
<Expression> Additional conditions for index only.private final int
private static final Comparator
<Expression> private final List
<Expression> Use an ArrayDeque because we primarily insert at the front.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
ConstructorsConstructorDescriptionConditionAndOrN
(int andOrType, List<Expression> expressions) ConditionAndOrN
(int andOrType, Expression expr1, Expression expr2, Expression expr3) -
Method Summary
Modifier and TypeMethodDescriptionvoid
addFilterConditions
(TableFilter filter) Add conditions to a table filter if they can be evaluated.(package private) void
Add the expression at the beginning of the list.void
createIndexConditions
(SessionLocal session, TableFilter filter) Create index conditions if possible and attach them to the table filter.(package private) int
int
getCost()
Estimate the cost to process the expression.getNotIfPossible
(SessionLocal session) If it is possible, return the negated expression.getSubexpression
(int index) Returns subexpression with specified index.int
Returns count of subexpressions.getUnenclosedSQL
(StringBuilder builder, int sqlFlags) Get the SQL statement of this expression.getValue
(SessionLocal session) Return the resulting value for the current row.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.boolean
Returns whether this expressions needs to be wrapped in parentheses when it is used as an argument of other expressions.optimize
(SessionLocal session) Try to optimize the expression.private boolean
optimizeMerge
(int i) void
setEvaluatable
(TableFilter tableFilter, boolean b) 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.condition.Condition
castToBoolean, getType
Methods inherited from class org.h2.expression.Expression
getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, 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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andOrType
private final int andOrType -
expressions
Use an ArrayDeque because we primarily insert at the front. -
added
Additional conditions for index only. -
COMPARE_BY_COST
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Constructor Details
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ConditionAndOrN
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ConditionAndOrN
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Method Details
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getAndOrType
int getAndOrType() -
addFirst
Add the expression at the beginning of the list.- Parameters:
e
- the expression
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needParentheses
public boolean needParentheses()Description copied from class:Expression
Returns whether this expressions needs to be wrapped in parentheses when it is used as an argument of other expressions.- Overrides:
needParentheses
in classExpression
- Returns:
true
if it is
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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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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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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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optimize
Description copied from class:Expression
Try to optimize the expression.- Specified by:
optimize
in classExpression
- Parameters:
session
- the session- Returns:
- the optimized expression
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optimizeMerge
private boolean optimizeMerge(int i) -
addFilterConditions
Description copied from class:Expression
Add conditions to a table filter if they can be evaluated.- Overrides:
addFilterConditions
in classExpression
- Parameters:
filter
- the table filter
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mapColumns
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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setEvaluatable
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 filterb
- true if the table filter can return value
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updateAggregate
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
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
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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