PrimaryKey

java.lang.Object
- org.datanucleus.store.rdbms.key.Key
- - org.datanucleus.store.rdbms.key.PrimaryKey

```
public class PrimaryKey
extends Key
```
Representation of the primary key of a table. TODO MariaDB apparently allows "ALTER TABLE ADD CONSTRAINT PRIMARY KEY (col1 ASC, col2 DESC)" not that many others do but we don't allow that here, would need to extend ColumnOrderedKey for that, plus update to MySQL Adapter

Field Summary
- Fields inherited from class org.datanucleus.store.rdbms.key.Key
  columns, name, table

Constructor Summary

Constructors
Constructor Description

PrimaryKey(Table table)
Creates a primary key.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`equals(java.lang.Object obj)`	Equality operator.
`int`	`hashCode()`	Hashcode operator.
`java.lang.String`	`toString()`	Stringifier method.

Methods inherited from class org.datanucleus.store.rdbms.key.Key
addColumn, assertSameDatastoreObject, getColumnList, getColumnList, getColumns, getName, getNumberOfColumns, getTable, setColumn, setListMinimumSize, setName

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - PrimaryKey
```
public PrimaryKey(Table table)
```
    Creates a primary key. A default name of the primary key is created by the constructor. This name can be overwritten.
    
    Parameters:
    
    table - Table that this is the PK for
- Method Detail
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Description copied from class: Key
    
    Equality operator.
    
    Overrides:
    
    equals in class Key
    
    Parameters:
    
    obj - Object to compare against
    
    Returns:
    
    Whether they are equal.
  - hashCode
```
public int hashCode()
```
    Description copied from class: Key
    
    Hashcode operator.
    
    Overrides:
    
    hashCode in class Key
    
    Returns:
    
    The hashcode
  - toString
```
public java.lang.String toString()
```
    Stringifier method. Generates a form of the PK ready to be used in a DDL statement. e.g
    PRIMARY KEY (col1,col2)
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    The string form of this object. Ready to be used in a DDL statement.