Package org.apache.empire.db.expr.column

Class DBScalarExpr

java.lang.Object

org.apache.empire.db.DBObject

org.apache.empire.db.DBExpr

org.apache.empire.db.DBColumnExpr

org.apache.empire.db.expr.column.DBScalarExpr

All Implemented Interfaces:

ColumnExpr, DBPreparable

public class DBScalarExpr
extends DBColumnExpr
implements DBPreparable

This class is used for declaring scalar functions in SQL (like e.g. random).

Field Summary

Fields

Modifier and Type	Field	Description
final DataType	dataType
final DBDatabase	db
protected static final org.slf4j.Logger	log
protected Object[]	params
final String	template

Fields inherited from class org.apache.empire.db.DBColumnExpr

attributes, beanPropertyName, options

Fields inherited from class org.apache.empire.db.DBExpr

CTX_ALIAS, CTX_ALL, CTX_DEFAULT, CTX_FULLNAME, CTX_NAME, CTX_NOPARENTHESIS, CTX_VALUE

Constructor Summary

Constructors

Constructor	Description
DBScalarExpr(DBDatabase db, String template, Object[] params, DataType dataType)	Constructs a new DBValueExpr object.
DBScalarExpr(DBDatabase db, String template, Object param, DataType dataType)	Constructs a new DBValueExpr object.

Method Summary

Modifier and Type	Method	Description
void	addReferencedColumns(Set<DBColumn> list)	Internal function to obtain all DBColumnExpr-objects used by this expression.
void	addSQL(DBSQLBuilder sql, long context)	Creates the SQL-Command.
Element	addXml(Element parent, long flags)	this helper function calls the DBColumnExpr.addXML(Element, long) method
boolean	equals(Object other)	Returns true if other is equal to this expression
final DBDatabase	getDatabase()	Returns the current DBDatabase object.
DataType	getDataType()	Returns the data type of the DBColumnExpr object.
Class<Enum<?>>	getEnumType()	Returns null
String	getName()	Returns the column name.
Object[]	getParams()	return the value associated with this value expression
DBRowSet	getRowSet()	Returns null.
DBColumn	getUpdateColumn()	Returns null.
boolean	isAggregate()	Always returns false since value expressions cannot be an aggregate.
void	prepareParams(DBCommand cmd, DBExpr parent)	Prepares an expression for a query This function is called by DBCommand in order to add values as query parameters instead of being literally included in the sql statement Please Note: This function is internally called.
void	setParams(Object[] params)	set the value associated with this value expression

Methods inherited from class org.apache.empire.db.DBColumnExpr

abs, aggregate, append, as, as, asc, avg, ceiling, cmp, coalesce, concat, concat, contains, convertTo, convertTo, count, countDistinct, day, decode, decode, decode, decode, decode, decode, decodeEnum, decodeSort, desc, divideBy, floor, format, function, getAttribute, getAttribute, getBeanPropertyName, getControlType, getDefaultSortOrder, getExprFromPhrase, getExprFromPhrase, getIgnoreCaseExpr, getJavaType, getNumberType, getOptions, getSourceColumn, getTitle, in, in, in, indexOf, indexOf, indexOf, is, isBetween, isCaseSensitive, isGreaterThan, isLessOrEqual, isLiteralValue, isMoreOrEqual, isNot, isNotBetween, isSmallerThan, length, like, like, likeLower, likeUpper, lower, max, min, minus, minus, modulo, month, multiplyWith, notContains, notIn, notIn, notIn, notLike, nvl, on, parenthesis, plus, plus, prepend, qualified, replace, reverse, round, setAttribute, setBeanPropertyName, setControlType, setDefaultSortOrder, setOptions, setTitle, stringAgg, stringAgg, substring, substring, substring, substring, substring, substring, sum, toChar, toChar, toString, trim, trimLeft, trimRight, trunc, upper, when, year

Methods inherited from class org.apache.empire.db.DBObject

checkParamNull

Methods inherited from class java.lang.Object

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

Field Details

log

protected static final org.slf4j.Logger log

db

public final DBDatabase db

dataType

public final DataType dataType

template

public final String template

params

protected Object[] params

Constructor Details

DBScalarExpr

public DBScalarExpr(DBDatabase db,
 String template,
 Object[] params,
 DataType dataType)

Constructs a new DBValueExpr object.

Parameters:

db - the database

template - the format template

params - the format params

dataType - the data type for this constant

DBScalarExpr

public DBScalarExpr(DBDatabase db,
 String template,
 Object param,
 DataType dataType)

Constructs a new DBValueExpr object.

Parameters:

db - the database

template - the format template

param - a format param

dataType - the data type for this constant

Method Details

getParams

public Object[] getParams()

return the value associated with this value expression

Returns:

the current value

setParams

public void setParams(Object[] params)

set the value associated with this value expression

Parameters:

params - the params array

getDatabase

public final DBDatabase getDatabase()

Returns the current DBDatabase object.

Specified by:

getDatabase in class DBObject

Returns:

the current DBDatabase object

getDataType

public DataType getDataType()

Returns the data type of the DBColumnExpr object.

Specified by:

getDataType in interface ColumnExpr

Specified by:

getDataType in class DBColumnExpr

Returns:

the data type

See Also:

• DataType

getEnumType

public Class<Enum<?>> getEnumType()

Returns null

Specified by:

getEnumType in interface ColumnExpr

Returns:

the enum type

getName

public String getName()

Returns the column name.

Specified by:

getName in interface ColumnExpr

Specified by:

getName in class DBColumnExpr

Returns:

the column name

getRowSet

public DBRowSet getRowSet()

Returns null.

Specified by:

getRowSet in class DBColumnExpr

Returns:

null

getUpdateColumn

public DBColumn getUpdateColumn()

Returns null.

Specified by:

getUpdateColumn in interface ColumnExpr

Specified by:

getUpdateColumn in class DBColumnExpr

Returns:

null

isAggregate

public boolean isAggregate()

Always returns false since value expressions cannot be an aggregate.

Specified by:

isAggregate in class DBColumnExpr

Returns:

false

equals

public boolean equals(Object other)

Returns true if other is equal to this expression

Overrides:

equals in class Object

prepareParams

public void prepareParams(DBCommand cmd,
 DBExpr parent)

Description copied from interface: DBPreparable

Prepares an expression for a query This function is called by DBCommand in order to add values as query parameters instead of being literally included in the sql statement Please Note: This function is internally called. Do not call yourself!

Specified by:

prepareParams in interface DBPreparable

Parameters:

cmd - the command to which to add the parameters

parent - the parent expression holding the value

addReferencedColumns

public void addReferencedColumns(Set<DBColumn> list)

Description copied from class: DBExpr

Internal function to obtain all DBColumnExpr-objects used by this expression.

Specified by:

addReferencedColumns in class DBExpr

Parameters:

list - list to which all used column expressions must be added

See Also:

• DBExpr.addReferencedColumns(Set)

addSQL

public void addSQL(DBSQLBuilder sql,
 long context)

Creates the SQL-Command.

Specified by:

addSQL in class DBExpr

Parameters:

sql - the SQL-Command

context - the current SQL-Command context

addXml

public Element addXml(Element parent,
 long flags)

this helper function calls the DBColumnExpr.addXML(Element, long) method

Specified by:

addXml in class DBColumnExpr

Parameters:

parent - the parent element to which to append the column description

flags - currently not used

Returns:

the newly created child element