Package de.aristaflow.adept2.base.dbaccess

Class ParentToChildConnection

java.lang.Object

de.aristaflow.adept2.base.dbaccess.ParentToChildConnection

public class ParentToChildConnection
extends Object

A parent-to-child connection joins the parent attribute of a hierarchical table with a corresponding child attribute via the designated operator. The designated attributes should be valid attributes of the corresponding table.

Author:

Ulrich Kreher

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ParentToChildConnection(String parentAttribute, boolean parentConstant, String operator, String childAttribute, boolean childConstant)	Creates a new parent-to-child-connection to use in a hierarchical query.
	ParentToChildConnection(String parentAttribute, String operator, String childAttribute)	Creates a new parent-to-child-connection to use in a hierarchical query.
	ParentToChildConnection(String attribute, String operator, String value, boolean childAttribute)	Creates a new condition to compare a parent or child attribute with a constant.

Method Summary

Modifier and Type	Method	Description
String	getChildAttribute()	Gets the attribute of the child-tuples to use to join parent-tuples with.
String	getOperator()	Gets the operator used to join parent- and child-tuples.
String	getParentAttribute()	Gets the attribute of the parent-tuples to use to join child-tuples with.
boolean	isChildAttributeConstant()	Gets whether the attribute for the child tuples is a constant and should therefore not be prefixed.
boolean	isParentAttributeConstant()	Gets whether the attribute for the parent tuples is a constant and should therefore not be prefixed.

Methods inherited from class java.lang.Object

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

Constructor Detail

ParentToChildConnection

public ParentToChildConnection(String parentAttribute,
                               String operator,
                               String childAttribute)

Creates a new parent-to-child-connection to use in a hierarchical query. It has to be ensured, that the designated attributes are legal. Take care if the column of both attributes can be NULL! In this case the join may fail since NULL = NULL is false so the corresponding tuple will not be in the join and therefore in the recursion step. In this case you will need to add two additional parent child connections using <parentAttribute>, "IS", "NULL", false and <childAttribute>, "IS", NULL, true

Parameters:

parentAttribute - The attribute of the parent-tuples to use in the join. If the columns of this attribute and the child attribute are nullable, you will need to add two additional parent to child connections for comparing each attribute with the constant NULL.

operator - The operator used to join parent- and child-tuples.

childAttribute - The attribute of the parent-tuples to use in the join. If the columns of this attribute and the child attribute are nullable, you will need to add two additional parent to child connections for comparing each attribute with the constant NULL.

ParentToChildConnection

public ParentToChildConnection(String attribute,
                               String operator,
                               String value,
                               boolean childAttribute)

Creates a new condition to compare a parent or child attribute with a constant.

Parameters:

attribute - The attribute of either the parent or the child tuples to compare with a constant.

operator - The operator used to compare the attribute with a constant value.

value - The (constant) value with which to compare the attribute.

childAttribute - Whether the attribute is a child attribute (or a parent attribute). This is used to prefix the attribute appropriately so that it refers to the right table.

ParentToChildConnection

protected ParentToChildConnection(String parentAttribute,
                                  boolean parentConstant,
                                  String operator,
                                  String childAttribute,
                                  boolean childConstant)

Creates a new parent-to-child-connection to use in a hierarchical query. Attributes may be constants which means, they select from the parent- or child-tuples. It has to be ensured, that the designated attributes are legal.

Parameters:

parentAttribute - The attribute of the parent-tuples to use in the join.

parentConstant - Whether the attribute for the parent tuples is a constant and should therefore not be prefixed. In this case it selects from the child tuples.

operator - The operator used to join parent- and child-tuples.

childAttribute - The attribute of the parent-tuples to use in the join.

childConstant - Whether the attribute for the child tuples is a constant and should therefore not be prefixed. In this case it selects from the parent tuples.

Method Detail

getParentAttribute

public String getParentAttribute()

Gets the attribute of the parent-tuples to use to join child-tuples with.

Returns:

The attribute of the parent-tuples to use to join child-tuples with.

isParentAttributeConstant

public boolean isParentAttributeConstant()

Gets whether the attribute for the parent tuples is a constant and should therefore not be prefixed. In this case it selects from the child tuples. A constant attribute is used on the right side of the operator.

Returns:

Whether the attribute for the parent tuples is a constant and should therefore not be prefixed. In this case it selects from the child tuples.

getOperator

public String getOperator()

Gets the operator used to join parent- and child-tuples.

Returns:

The operator used to join parent- and child-tuples.

getChildAttribute

public String getChildAttribute()

Gets the attribute of the child-tuples to use to join parent-tuples with.

Returns:

The attribute of the child-tuples to use to join parent-tuples with.

isChildAttributeConstant

public boolean isChildAttributeConstant()

Gets whether the attribute for the child tuples is a constant and should therefore not be prefixed. In this case it selects from the parent tuples. A constant attribute is used on the right side of the operator.

Returns:

Whether the attribute for the child tuples is a constant and should therefore not be prefixed. In this case it selects from the parent tuples.