nz.co.gregs.dbvolution.datatypes

Class DBNumberStatistics

java.lang.Object

nz.co.gregs.dbvolution.datatypes.QueryableDatatype<Number>

nz.co.gregs.dbvolution.datatypes.DBNumber

nz.co.gregs.dbvolution.datatypes.DBNumberStatistics

All Implemented Interfaces:

Serializable, DBExpression, ExpressionCanHaveNullValues, ExpressionHasStandardStringResult, NumberResult

public class DBNumberStatistics
extends DBNumber

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Author:

gregorygraham

See Also:

Serialized Form

Field Summary

Fields inherited from class nz.co.gregs.dbvolution.datatypes.QueryableDatatype

SORT_ASCENDING, SORT_DESCENDING

Constructor Summary

Constructors

Constructor and Description
DBNumberStatistics() The default constructor for DBNumberStatistics.
DBNumberStatistics(IntegerExpression numberExpressionToGenerateStatsFrom) Creates a column expression with a statistics result from the expression provided.
DBNumberStatistics(NumberExpression numberExpressionToGenerateStatsFrom) Creates a column expression with a statistics result from the expression provided.

Method Summary

Methods

Modifier and Type	Method and Description
Number	average() The average value of the grouping.
DBNumberStatistics	copy() Copies a QueryableDatatype and returns the copy.
Number	count() Count of the rows included in this set of statistics Support DBvolution at Patreon
Number	firstQuartile() Support DBvolution at Patreon
protected Number	getFromResultSet(DBDefinition database, ResultSet resultSet, String fullColumnName) Returns the correct object from the ResultSet for the QueryableDatatype to handle.
protected Number	getFromResultSet(DBDefinition database, ResultSet resultSet, String fullColumnName, int offset)
DBNumber	getQueryableDatatypeForExpressionValue() Provides a blank instance of the QueryableDatatype used by this expression.
String	getSQLDatatype() Support DBvolution at Patreon
boolean	isAggregator() Returns TRUE if this expression is an Aggregator like SUM() or LEAST().
Number	max() Support DBvolution at Patreon
Number	median() The middle term in the grouping.
Number	min() Support DBvolution at Patreon
Number	secondQuartile() The middle term in the grouping.
void	setFromResultSet(DBDefinition database, ResultSet resultSet, String resultSetColumnName) Used internally to set the QDT to the value returned from the database.
Number	standardDeviation()
Number	sum() Returns the sum of all the numbers in this group.
Number	thirdQuartile() Support DBvolution at Patreon
String	toString()

Methods inherited from class nz.co.gregs.dbvolution.datatypes.DBNumber

doubleValue, excludedRange, excludedRange, excludedRangeExclusive, excludedRangeExclusive, excludedRangeInclusive, excludedRangeInclusive, excludedValues, excludedValues, excludedValues, formatValueForSQLStatement, getIncludesNull, getNumericPrecision, getNumericScale, getTablesInvolved, getValue, intValue, longValue, numberValue, permittedRange, permittedRange, permittedRangeExclusive, permittedRangeExclusive, permittedRangeInclusive, permittedRangeInclusive, permittedValues, permittedValues, permittedValues, setValue, setValue, setValueFromStandardStringEncoding, stringResult

Methods inherited from class nz.co.gregs.dbvolution.datatypes.QueryableDatatype

clear, equals, formatColumnForSQLStatement, getColumnExpression, getLiteralValue, getOperator, getPreviousSQLValue, getPreviousValue, getPropertyWrapperDefinition, getQueryableDatatypeForObject, getQueryableDatatypeInstance, getSortOrder, hasBeenSet, hasChanged, hasColumnExpression, hashCode, includingNulls, isDefined, isNotNull, isNull, isPurelyFunctional, negateOperator, removeConstraints, setChanged, setColumnExpression, setDefined, setLiteralValue, setOperator, setPreviousValue, setSortOrderAscending, setSortOrderDescending, setToNull, setToNull, setUnchanged, setValueToNull, stringValue, toSQLString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface nz.co.gregs.dbvolution.expressions.DBExpression

isPurelyFunctional, toSQLString

Constructor Detail

DBNumberStatistics

public DBNumberStatistics()

The default constructor for DBNumberStatistics.

Creates an unset undefined DBNumber object.

Use DBNumberStatistics(nz.co.gregs.dbvolution.expressions.NumberExpression) instead.

DBNumberStatistics

public DBNumberStatistics(NumberExpression numberExpressionToGenerateStatsFrom)

Creates a column expression with a statistics result from the expression provided.

Used in DBReport, and some DBRow, sub-classes to derive data from the database prior to retrieval.

Parameters:

numberExpressionToGenerateStatsFrom - numberExpression

DBNumberStatistics

public DBNumberStatistics(IntegerExpression numberExpressionToGenerateStatsFrom)

Creates a column expression with a statistics result from the expression provided.

Used in DBReport, and some DBRow, sub-classes to derive data from the database prior to retrieval.

Parameters:

numberExpressionToGenerateStatsFrom - numberExpression

Method Detail

count

public Number count()

Count of the rows included in this set of statistics

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Returns:

the size of the statistics collection

sum

public Number sum()

Returns the sum of all the numbers in this group.

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Returns:

the sum of all values in this grouping

min

public Number min()

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Returns:

the minimum (smallest) value in this grouping

max

public Number max()

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Returns:

the maximum (largest) value in this grouping

median

public Number median()

The middle term in the grouping.

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Returns:

the median value in this grouping

average

public Number average()

The average value of the grouping.

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Returns:

the average value of the grouping

firstQuartile

public Number firstQuartile()

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Returns:

the middle number between the median and the smallest value.

thirdQuartile

public Number thirdQuartile()

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Returns:

the middle number between the median and the largest value.

secondQuartile

public Number secondQuartile()

The middle term in the grouping.

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Returns:

the median value in this grouping

getSQLDatatype

public String getSQLDatatype()

Description copied from class: DBNumber

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Overrides:

getSQLDatatype in class DBNumber

Returns:

the default database type as a string, may be gazumped by the DBDefinition

isAggregator

public boolean isAggregator()

Description copied from interface: DBExpression

Returns TRUE if this expression is an Aggregator like SUM() or LEAST().

Subclasses must implement this method returning TRUE if the expression will combine the results of several rows to produce a result. If the expression relies on subexpressions, then the isAggregator method must return TRUE if the subexpressions include an aggregator.

Aggregators collect several rows together to produce a single result. Examples are MAX, MIN, and AVERAGE.

They are only appropriate in the SELECT clause and generally require the GROUP BY clause to be useful.

Aggregators are used with DBReport. Aggregator expressions are included in the SELECT clause but excluded from the GROUP BY clause.

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Specified by:

isAggregator in interface DBExpression

Overrides:

isAggregator in class DBNumber

Returns:

TRUE if this DBExpression represents an aggregating functions

copy

public DBNumberStatistics copy()

Description copied from class: QueryableDatatype

Copies a QueryableDatatype and returns the copy. Used internally to provide immutability to DBOperator objects. The intention is that this method will provide a snapshot of the QDT at this moment in time and copy or clone any internal objects that might change. Subclasses should extend this method if they have fields that maintain the state of the QDT. Always use the super.copy() method first when overriding this method.

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Specified by:

copy in interface DBExpression

Specified by:

copy in interface NumberResult

Overrides:

copy in class DBNumber

Returns:

a complete copy of the QDT with all values set.

getFromResultSet

protected Number getFromResultSet(DBDefinition database,
                      ResultSet resultSet,
                      String fullColumnName)
                           throws SQLException

Description copied from class: QueryableDatatype

Returns the correct object from the ResultSet for the QueryableDatatype to handle.

Overrides:

getFromResultSet in class DBNumber

Parameters:

database - database

resultSet - resultSet

fullColumnName - fullColumnName

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Returns:

the expected object from the ResultSet. 1 Database exceptions may be thrown

Throws:

SQLException - java.sql.SQLException

getFromResultSet

protected Number getFromResultSet(DBDefinition database,
                      ResultSet resultSet,
                      String fullColumnName,
                      int offset)
                           throws SQLException

Throws:

SQLException

getQueryableDatatypeForExpressionValue

public DBNumber getQueryableDatatypeForExpressionValue()

Description copied from interface: DBExpression

Provides a blank instance of the QueryableDatatype used by this expression.

You are probably looking for ExpressionColumn.asExpressionColumn().

Note that this method is not good for use in everyday DBvolution code and should probably be reserved for meta-programming.

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Specified by:

getQueryableDatatypeForExpressionValue in interface DBExpression

Overrides:

getQueryableDatatypeForExpressionValue in class DBNumber

Returns:

the QueryableDatatype subclass that corresponds to the results of this expression

setFromResultSet

public void setFromResultSet(DBDefinition database,
                    ResultSet resultSet,
                    String resultSetColumnName)
                      throws SQLException

Description copied from class: QueryableDatatype

Used internally to set the QDT to the value returned from the database.

If you create a new QDT you should override this method. The default implementation in QueryableDatatype processes the ResultSet column as a String. You should follow the basic pattern but change ResultSet.getString(String) to the required ResultSet method and add any required post-processing.

Note that most of the method is dedicated to detecting NULL values. This is very important as are the calls to QueryableDatatype.setUnchanged() and QueryableDatatype.setDefined(boolean)

Overrides:

setFromResultSet in class QueryableDatatype<Number>

Parameters:

database - database

resultSet - resultSet

resultSetColumnName - resultSetColumnName

Throws:

SQLException - Database exceptions may be thrown

toString

public String toString()

Overrides:

toString in class QueryableDatatype<Number>

standardDeviation

public Number standardDeviation()