nz.co.gregs.dbvolution.columns

Class BooleanArrayColumn

java.lang.Object

nz.co.gregs.dbvolution.expressions.BooleanArrayExpression

nz.co.gregs.dbvolution.columns.BooleanArrayColumn

All Implemented Interfaces:

ColumnProvider, DBExpression, ExpressionColumn<DBBooleanArray>, BooleanArrayResult, EqualComparable<BooleanArrayResult>, ExpressionCanHaveNullValues

public class BooleanArrayColumn
extends BooleanArrayExpression
implements ColumnProvider

Represents a database column storing an array of bits.

Bits are not BLOBs or large objects, rather they are a collection of boolean values stored as a single field in a byte array, or integer.

This class adds the necessary methods to use a collection of bits like a byte[].

Internally the class uses an AbsractColumn to store the column and overrides methods in BooleanArrayExpression to insert the column into the expression.

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Author:

Gregory Graham

See Also:

RowDefinition, AbstractColumn, BooleanArrayExpression

Constructor Summary

Constructors

Constructor and Description
BooleanArrayColumn(RowDefinition row, boolean[] field) Create a BooleanColumn for the supplied field of the supplied row
BooleanArrayColumn(RowDefinition row, DBBooleanArray field) Create a BooleanColumn for the supplied field of the supplied row

Method Summary

Methods

Modifier and Type	Method and Description
BooleanArrayColumn	copy() A Complete Copy Of This DBValue.
AbstractColumn	getColumn() Returns the AbstractColumn from this ColumnProvider.
Set<DBRow>	getTablesInvolved() Returns a Set of the DBRow instances involved in this expression.
BooleanExpression	is(DBBooleanArray boolArrayColumn) Creates an expression that will compare this column to the other column.
boolean	isAggregator() Returns TRUE if this expression is an Aggregator like SUM() or LEAST().
boolean	isPurelyFunctional() Indicates whether or not the expression includes table columns.
void	setUseTableAlias(boolean useTableAlias) Indicates whether the ColumnProvider should use the table alias during query creation.
String	toSQLString(DBDefinition db) Produces the snippet provided by this class.

Methods inherited from class nz.co.gregs.dbvolution.expressions.BooleanArrayExpression

asExpressionColumn, getIncludesNull, getInnerBooleanArrayResult, getQueryableDatatypeForExpressionValue, is, is, isNot, isNot, value

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BooleanArrayColumn

public BooleanArrayColumn(RowDefinition row,
                  boolean[] field)

Create a BooleanColumn for the supplied field of the supplied row

Parameters:

row - the row containing the field

field - the field representing the column

BooleanArrayColumn

public BooleanArrayColumn(RowDefinition row,
                  DBBooleanArray field)

Create a BooleanColumn for the supplied field of the supplied row

Parameters:

row - the row containing the field

field - the field representing the column

Method Detail

toSQLString

public String toSQLString(DBDefinition db)

Description copied from interface: DBExpression

Produces the snippet provided by this class.

This is only used internally.

If you are extending DBvolution and adding a new function this is the place to format the information for use in SQL. A DBDefinition instance is provided to supply context and so your SQL can used on multiple database engines.

Specified by:

toSQLString in interface DBExpression

Overrides:

toSQLString in class BooleanArrayExpression

Parameters:

db - the target database

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Returns:

the DBValue formatted as a SQL snippet

copy

public BooleanArrayColumn copy()

Description copied from interface: DBExpression

A Complete Copy Of This DBValue.

Immutability in DBvolution is maintain by internally copying objects.

This method enables immutability by performing a deep copy of the object.

Singletons may return themselves but all other objects must return a new instance with copies of all mutable fields.

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Specified by:

copy in interface DBExpression

Specified by:

copy in interface BooleanArrayResult

Overrides:

copy in class BooleanArrayExpression

Returns:

a copy of this DBValue

getColumn

public AbstractColumn getColumn()

Description copied from interface: ColumnProvider

Returns the AbstractColumn from this ColumnProvider.

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Specified by:

getColumn in interface ColumnProvider

Returns:

the column that this provider supplies.

getTablesInvolved

public Set<DBRow> getTablesInvolved()

Description copied from interface: DBExpression

Returns a Set of the DBRow instances involved in this expression.

Used by QueryGraph to plot the connections between tables and avoid cartesian joins.

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Specified by:

getTablesInvolved in interface DBExpression

Overrides:

getTablesInvolved in class BooleanArrayExpression

Returns:

a set of DBRow instances involved in this DBExpression.

setUseTableAlias

public void setUseTableAlias(boolean useTableAlias)

Description copied from interface: ColumnProvider

Indicates whether the ColumnProvider should use the table alias during query creation.

the standard implementation is this.column.setUseTableAlias(useTableAlias); and passes the boolean along to the underlying AbstractColumn

Specified by:

setUseTableAlias in interface ColumnProvider

Parameters:

useTableAlias - true or false

isPurelyFunctional

public boolean isPurelyFunctional()

Description copied from interface: DBExpression

Indicates whether or not the expression includes table columns.

Purely functional expressions use only in-built functions or literal values to produce results and do not require data from tables.

Some databases, notably MS SQLServer, can not group purely functional expressions.

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Specified by:

isPurelyFunctional in interface DBExpression

Overrides:

isPurelyFunctional in class BooleanArrayExpression

Returns:

TRUE if the expression does not access table data, otherwise FALSE.

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 BooleanArrayExpression

Returns:

TRUE if this DBExpression represents an aggregating functions

is

public BooleanExpression is(DBBooleanArray boolArrayColumn)

Creates an expression that will compare this column to the other column.

Parameters:

boolArrayColumn - the column to compare to

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Returns:

a BooleanExpression