dk.eobjects.metamodel.query
Class FromItem

java.lang.Object
  dk.eobjects.metamodel.query.FromItem

All Implemented Interfaces:

IQueryItem, java.io.Serializable, java.lang.Cloneable

public class FromItem
extends java.lang.Object
implements IQueryItem, java.lang.Cloneable

Represents a FROM item. FROM items can take different forms:

• table FROMs (eg. "FROM products p")
• join FROMs with an ON clause (eg. "FROM products p INNER JOIN orders o ON p.id = o.product_id")
• subquery FROMs (eg. "FROM (SELECT * FROM products) p")

See Also:

FromClause, Serialized Form

Constructor Summary

FromItem(JoinType join, FromItem leftSide, FromItem rightSide, SelectItem[] leftOn, SelectItem[] rightOn)
Constructor for advanced join types with custom relationships

FromItem(JoinType join, Relationship relationship)
Constructor for join FROM clauses that join two tables using their relationship.

FromItem(Query subQuery)
Constructor for sub-query FROM clauses

FromItem(java.lang.String expression)
Creates a single unvalidated from item based on a expression.

FromItem(Table table)
Constructor for table FROM clauses

Method Summary

protected FromItem	clone()
boolean	equals(java.lang.Object obj)
java.lang.String	getAlias()
java.lang.String	getAlias(Table table) Gets the alias of a table, if it is registered (and visible, ie.
java.lang.String	getExpression()
JoinType	getJoin()
SelectItem[]	getLeftOn()
FromItem	getLeftSide()
Query	getQuery()
SelectItem[]	getRightOn()
FromItem	getRightSide()
java.lang.String	getSameQueryAlias()
Query	getSubQuery()
Table	getTable()
FromItem	setAlias(java.lang.String alias)
IQueryItem	setQuery(Query query)
java.lang.String	toString()
java.lang.String	toStringNoAlias()

Methods inherited from class java.lang.Object

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

Constructor Detail

FromItem

public FromItem(Table table)

Constructor for table FROM clauses

FromItem

public FromItem(Query subQuery)

Constructor for sub-query FROM clauses

Parameters:

subQuery - the subquery to use

FromItem

public FromItem(JoinType join,
                Relationship relationship)

Constructor for join FROM clauses that join two tables using their relationship. The primary table of the relationship will be the left side of the join and the foreign table of the relationship will be the right side of the join.

Parameters:

join - the join type to use

relationship - the relationship to use for joining the tables

FromItem

public FromItem(JoinType join,
                FromItem leftSide,
                FromItem rightSide,
                SelectItem[] leftOn,
                SelectItem[] rightOn)

Constructor for advanced join types with custom relationships

Parameters:

join - the join type to use

leftSide - the left side of the join

rightSide - the right side of the join

leftOn - what left-side select items to use for the ON clause

rightOn - what right-side select items to use for the ON clause

FromItem

public FromItem(java.lang.String expression)

Creates a single unvalidated from item based on a expression. Expression based from items are typically NOT datastore-neutral but are available for special "hacking" needs. Expression based from items can only be used for JDBC based datastores since they are translated directly into SQL.

Parameters:

expression - An expression to use for the from item, for example "MYTABLE".

Method Detail

getAlias

public java.lang.String getAlias()

getSameQueryAlias

public java.lang.String getSameQueryAlias()

setAlias

public FromItem setAlias(java.lang.String alias)

getTable

public Table getTable()

getSubQuery

public Query getSubQuery()

getJoin

public JoinType getJoin()

getLeftSide

public FromItem getLeftSide()

getRightSide

public FromItem getRightSide()

getLeftOn

public SelectItem[] getLeftOn()

getRightOn

public SelectItem[] getRightOn()

getExpression

public java.lang.String getExpression()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toStringNoAlias

public java.lang.String toStringNoAlias()

getAlias

public java.lang.String getAlias(Table table)

Gets the alias of a table, if it is registered (and visible, ie. not part of a sub-query) in the FromItem

Parameters:

table - the table to get the alias for

Returns:

the alias or null if none is found

getQuery

public Query getQuery()

Specified by:

getQuery in interface IQueryItem

setQuery

public IQueryItem setQuery(Query query)

Specified by:

setQuery in interface IQueryItem

clone

protected FromItem clone()

Overrides:

clone in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object