public ForeignKey(string psTableA, string psColumnA, string psTableB, string psColumnB)
 {
     TableA = new ForeignKeyField(psTableA, psColumnA);
     TableB = new ForeignKeyField(psTableB, psColumnB);
 }
 public ForeignKey(ForeignKeyField poTableA, ForeignKeyField poTableB)
 {
     TableA = new ForeignKeyField(poTableA.Table, poTableA.Column);
     TableB = new ForeignKeyField(poTableB.Table, poTableB.Column);
 }
 public ForeignKey()
 {
     TableA = new ForeignKeyField();
     TableB = new ForeignKeyField();
 }