====== Relation ======

**''public class Relation''**, \\
**''implements Serializable''**

Relation describes an SQL relation, that is determined with name and the arity, and in addition it can contain primary key definition.

===== Class Attributes =====
<code java>
private long id;
private java.lang.String name;
private int arity;
private int primaryKey; 
private java.lang.String description;
private java.util.ArrayList<java.lang.String> attributeNames;
</code>

===== Class Constructors =====
==== Relation ==== 
<code java>
public Relation (java.lang.String name, 
                 int arity, 
                 int primaryKey, 
                 java.lang.String description)
</code>
Constructor for relation with well known arity. Attributes are load inside the function by calling ''[[#readattributesnamesindescription|readAttributesNamesInDescritpion]]''\\

//Called by://
  * it.unibz.inf.magik.additional.InvolvedVariablesDetector
  * it.unibz.inf.magik.db.DatabaseConnector
  * it.unibz.inf.magik.test.CycleDetectionTest
  * it.unibz.inf.magik.test.TestFK
  * it.unibz.inf.magik.test.TestFK2
  * it.unibz.inf.magik.test.TestHardCaseFDCandFK
  * it.unibz.inf.magik.test.TestTCQCReasonerBlackWhiteExample
  * it.unibz.inf.magik.test.TestTCQCReasonerPlainCompanyEx
  * it.unibz.inf.magik.test.TestValQueryProblem
  * it.unibz.inf.magik.test.TestTCQCReasonerUnderFDC
  * it.unibz.inf.magik.test.TestQueryClass
  * it.unibz.inf.magik.test.TestQueryGeneralization
  * it.unibz.inf.magik.test.TestQueryToSQL
  * it.unibz.inf.magik.test.TestTCQCReasonerFKandFD
  * it.unibz.inf.magik.test.TestTCQCReasonerPlainSchoolEx
  * it.unibz.inf.magik.test.TestTCQCReasonerTCSuggestions
  * it.unibz.inf.magik.test.TestPrimaryVioation
**Parameters:**
  * name - name of the relation
  * arity - arity of the relation
  * primaryKey - determined with first place in the relation
  * description - string of the attributes of the relation, separated by comma


----
==== Relation ==== 
<code java>
public Relation (java.lang.String name, 
                 int primaryKey, 
                 java.lang.String description)
</code>
Constructor for relation without knowning arity. Attributes are load inside the function by calling ''[[#readattributesnamesindescription|readAttributesNamesInDescritpion]]''\\

//Called by://
  * it.unibz.inf.magik.web.SessionControl
  * it.unibz.inf.magik.test.TestSimpleComparison
**Parameters:**
  * name - name of the relation
  * primaryKey - determined with first place in the relation
  * description - string of the attributes of the relation, separated by comma
===== Class Methods =====

==== readAttributesNamesInDescription ====
<code java>
public static java.util.ArrayList<java.lang.String> readAttributesNamesInDescription(java.lang.String description)
</code>
Parse the attribute name of a relation from the description field

**Parameters:**
  * description - string with attributes separated by comma
**Returns:**
  * list of the attribute parsed


----

==== getAttributePosition ====
<code java>
public int getAttributePosition (java.lang.String attributeName)
</code>
Get attribute position in the relation

**Parameters:**
  * attributeName - attribute to search
**Returns:**
  * position in the relation, //-1// if not in the relation


----

==== getters and setters methods ====

<code java>
public java.util.ArrayList<java.lang.String> getAttributeNames()
public void setAttributeNames(java.util.ArrayList<java.lang.String> attributeNames) 

public java.lang.String getName() 
public void setName(java.lang.String name) 

public int getArity() 
public void setArity(int arity) 

public int getPrimaryKey()
public void setPrimaryKey(int primaryKey) 

public long getId()
public void setId(long id)

</code>

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