public void addForeignKeyConstraint(String name,String sourceField,String targetField,String targetTable){
  ForeignKeyConstraint foreignKey=new ForeignKeyConstraint(name,sourceField,targetField,targetTable);
  addForeignKeyConstraint(foreignKey);
}

public void addForeignKeyConstraint ( String name , String sourceField , String targetField , String targetTable ) { ForeignKeyConstraint foreignKey = new ForeignKeyConstraint ( name , sourceField , targetField , targetTable ) ; addForeignKeyConstraint ( foreignKey ) ; }
public : add a foreign key constraint to the table . if there is a same name foreign key constraint already , nothing will happen .
