2.17.2: 2011-06-17

net.sf.basedb.core
Class RealJoin

java.lang.Object
  extended by net.sf.basedb.core.RealJoin
All Implemented Interfaces:
Join, QueryElement

 class RealJoin
extends Object
implements Join

Represents a join from one virtual table in the dynamic database to a table in the regular database. virtualTable vt JOIN regularTable rt ON rt.id = vt.leftColumn.

Note that the join is always done to the id of the items in the regular table.

Version:
2.0
Author:
Nicklas
See Also:
RealTable
Last modified
$Date: 2010-04-21 11:48:29 +0200 (Wed, 21 Apr 2010) $

Field Summary
private  JoinType joinType
           
private  VirtualTable left
           
private  VirtualColumn leftColumn
           
private  RealTable right
           
 
Constructor Summary
RealJoin(JoinType joinType, VirtualTable left, RealTable right, VirtualColumn leftColumn)
          Create a new join to a regular table.
 
Method Summary
 boolean equals(Object other)
          This join is equal to another RealJoin if they join between the same tables using the same columns and join types.
 Collection<? extends QueryElement> getChildren()
          Get the children of this query element or null if it has no children.
 String getThetaJoin(Query query, DbControl dc)
           
 String getThetaJoinCondition(Query query, DbControl dc)
           
 int hashCode()
           
 String toQl(Query query, DbControl dc)
          Create a query language string of the query element.
 String toString()
           
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

joinType

private final JoinType joinType

left

private final VirtualTable left

right

private final RealTable right

leftColumn

private final VirtualColumn leftColumn
Constructor Detail

RealJoin

RealJoin(JoinType joinType,
         VirtualTable left,
         RealTable right,
         VirtualColumn leftColumn)
Create a new join to a regular table. SELECT ... FROM left JOIN right ON right.id = left.column.

Parameters:
joinType - The type of join
left - The left table to join from, if not specified we join from the root table
right - The table to join to
leftColumn - The column in the left table to join from, we always join to the id of the real table
Method Detail

toQl

public String toQl(Query query,
                   DbControl dc)
            throws BaseException
Description copied from interface: QueryElement
Create a query language string of the query element. Use the Query.getQueryType() method to find out which query language is wanted in case the element requires different syntax for different languages.

Specified by:
toQl in interface QueryElement
Parameters:
query - The query that is about to be executed
dc - The DbControl object used to execute the query
Throws:
BaseException - If there is any other error

getChildren

public Collection<? extends QueryElement> getChildren()
Description copied from interface: QueryElement
Get the children of this query element or null if it has no children. For example the AddExpression has two children, the expression beeing added.

Specified by:
getChildren in interface QueryElement
Returns:
Always null

getThetaJoin

public String getThetaJoin(Query query,
                           DbControl dc)
                    throws BaseException
Specified by:
getThetaJoin in interface Join
Throws:
BaseException

getThetaJoinCondition

public String getThetaJoinCondition(Query query,
                                    DbControl dc)
                             throws BaseException
Specified by:
getThetaJoinCondition in interface Join
Throws:
BaseException

toString

public String toString()
Overrides:
toString in class Object

equals

public boolean equals(Object other)
This join is equal to another RealJoin if they join between the same tables using the same columns and join types.

Overrides:
equals in class Object

hashCode

public int hashCode()
Overrides:
hashCode in class Object

2.17.2: 2011-06-17