org.apache.empire.db.expr.join

Class DBCrossJoinExpr

java.lang.Object

org.apache.empire.db.DBObject

org.apache.empire.db.DBExpr

org.apache.empire.db.expr.join.DBJoinExpr

org.apache.empire.db.expr.join.DBCrossJoinExpr

All Implemented Interfaces:

DBPreparable

public class DBCrossJoinExpr
extends DBJoinExpr

This class is used for building a join expression of an SQL statement. There is no need to explicitly create instances of this class.

Field Summary

Fields

Modifier and Type	Field and Description
protected DBRowSet	left
protected DBRowSet	right

Fields inherited from class org.apache.empire.db.expr.join.DBJoinExpr

type

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 and Description
DBCrossJoinExpr(DBRowSet left, DBRowSet right) Constructs a new DBJoinExpr object initialize this object with the left and right column and the data type of the join expression.

Method Summary

Modifier and Type	Method and Description
void	addReferencedColumns(Set<DBColumn> list) Internal function to obtain all DBColumnExpr-objects used by this expression.
void	addSQL(DBSQLBuilder sql, long context) Not allowed, this operation have to be done in the DBCommand object.
DBJoinExpr	copy(DBCommand newCmd) Copy Command
boolean	equals(Object obj) Compares two DBJoinExpr objects.
DBDatabase	getDatabase() Returns the current DBDatabase object.
DBRowSet	getLeftTable() returns the RowSet on the left of the join
DBRowSet	getOuterTable() Returns the left table name if the data type= JOIN_LEFT and returns the right table if the data type= JOIN_RIGHT.
DBRowSet	getRightTable() returns the RowSet on the right of the join
boolean	isJoinOn(DBColumn column) returns true if this join is using the given column or false otherwise
boolean	isJoinOn(DBRowSet rowset) returns true if this join is using the given table or view or false otherwise
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	reverse() This function swaps the left and the right statements of the join expression.
void	setType(DBJoinType type) alters the join type for this join

Methods inherited from class org.apache.empire.db.expr.join.DBJoinExpr

getType

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

checkParamNull

Methods inherited from class java.lang.Object

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

Field Detail

left

protected DBRowSet left

right

protected DBRowSet right

Constructor Detail

DBCrossJoinExpr

public DBCrossJoinExpr(DBRowSet left,
                       DBRowSet right)

Constructs a new DBJoinExpr object initialize this object with the left and right column and the data type of the join expression.

Parameters:

left - left value

right - right value

Method Detail

getDatabase

public final DBDatabase getDatabase()

Returns the current DBDatabase object.

Specified by:

getDatabase in class DBObject

Returns:

the current DBDatabase object

getLeftTable

public DBRowSet getLeftTable()

returns the RowSet on the left of the join

Specified by:

getLeftTable in class DBJoinExpr

Returns:

the rowset on the left

getRightTable

public DBRowSet getRightTable()

returns the RowSet on the right of the join

Specified by:

getRightTable in class DBJoinExpr

Returns:

the rowset on the right

isJoinOn

public boolean isJoinOn(DBRowSet rowset)

returns true if this join is using the given table or view or false otherwise

Specified by:

isJoinOn in class DBJoinExpr

Parameters:

rowset - the rowset to check

Returns:

true if the join is on the given rowset

isJoinOn

public boolean isJoinOn(DBColumn column)

returns true if this join is using the given column or false otherwise

Specified by:

isJoinOn in class DBJoinExpr

Parameters:

column - the column to check

Returns:

true if the join is on the given column

getOuterTable

public DBRowSet getOuterTable()

Returns the left table name if the data type= JOIN_LEFT and returns the right table if the data type= JOIN_RIGHT. If the data type = JOIN_INNER the return value is null.

Specified by:

getOuterTable in class DBJoinExpr

Returns:

the current DBDatabase object

setType

public void setType(DBJoinType type)

alters the join type for this join

Overrides:

setType in class DBJoinExpr

Parameters:

type - the join type

reverse

public void reverse()

This function swaps the left and the right statements of the join expression.

Specified by:

reverse in class DBJoinExpr

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!

Parameters:

cmd - the command to which to add the parameters

parent - the parent expression holding the value

copy

public DBJoinExpr copy(DBCommand newCmd)

Copy Command

Specified by:

copy in class DBJoinExpr

Parameters:

newCmd - the new command object

Returns:

the join expression

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)

Not allowed, this operation have to be done in the DBCommand object.

Specified by:

addSQL in class DBExpr

Parameters:

sql - the string buffer used to build the sql command

context - context flag for this SQL-Command (see CTX_??? constants).

equals

public boolean equals(Object obj)

Compares two DBJoinExpr objects.

Overrides:

equals in class Object

Parameters:

obj - other DBJoinExpr object

Returns:

true if the other DBJoinExpr object is equal to this object