如何使用递归解决血缘关系判断？

我最近在做一个养猪场项目，有一个需求是当公猪与母猪配种时，要查询两头猪在四代以内是否有血缘关系，如果有则提示。我现在可以通过猪的特定标识在数据库表中找到它的父母，后面应该要如何去实现这个四代比对过程呢？这个需求我大概思路是用递归来做，请教高人们这个需要怎么做？递归是在sql里做判断还是在java代码端做判断？具体怎么做？最好有个代码示例

如果不考虑兄弟姐妹的话如下：
找到A的父母2人，祖父母4人(父母的父母)，曾祖父母8人(父母的父母的父母)
同理找到B的父母、祖父母、曾祖父母

判断他们每一代是否有重复即可，流程上能够从父母辈开始判断有重复即结束，是否向上继续追溯祖父母，同理无重复再追溯曾祖父母

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class Test {

    public static void main(String[] args) {
        Pig p15 = new Pig(15,null,null);
        Pig p14 = new Pig(14,null,null);
        Pig p13 = new Pig(13,null,null);
        Pig p12 = new Pig(12,null,null);
        Pig p11 = new Pig(11,null,null);
        Pig p10 = new Pig(10,null,null);
        Pig p9 = new Pig(9,null,null);
        Pig p8 = new Pig(8,null,null);
        Pig p7 = new Pig(7,p14,p15);
        Pig p6 = new Pig(6,p12,p13);
        Pig p5 = new Pig(5,p10,p11);
        Pig p4 = new Pig(4,p8,p9);
        Pig p3 = new Pig(3,p6,p7);
        Pig p2 = new Pig(2,p4,p5);
        Pig p1 = new Pig(1,p2,p3);
        Pig p16 = new Pig(1,p4,p5);

        System.out.println(find(p1,p16,4));
    }

    //  俺是pigA，她是pigB，俺俩配种
    public static boolean find(Pig pigA,Pig pigB,int generation){
        //  俺的4代祖宗
        List<Pig> aAncestry = new ArrayList<Pig>();
        //  她的4代祖宗
        List<Pig> bAncestry = new ArrayList<Pig>();

        //  添加俺爸和俺爸的祖宗
        if(pigA.father != null)
            addAncerstry(aAncestry,pigA.father,generation);
        //  添加俺妈和俺妈的祖宗
        if(pigA.mother != null)
            addAncerstry(aAncestry,pigA.mother,generation);

        //  添加她爸和她爸的祖宗
        if(pigB.father != null)
            addAncerstry(bAncestry,pigB.father,generation);
        //  添加她妈和她妈的祖宗
        if(pigB.mother != null)
            addAncerstry(bAncestry,pigB.mother,generation);

        //  祖宗对比
        for(Pig pigAancestry: aAncestry){
            for(Pig pigBancestry: bAncestry){
                //  同一个祖宗
                if(pigAancestry.getSelfId() == pigBancestry.getSelfId()){
                    System.out.println("俺祖宗："+pigAancestry.toString());
                    System.out.println("她祖宗："+pigBancestry.toString());
                    return true;
                }
            }
        }

        return false;
    }

    public static void addAncerstry(List<Pig> ancestry,Pig pig,int generation){
        if(generation == 1)
            return;
        ancestry.add(pig);
        if(pig.father != null)
            addAncerstry(ancestry,pig.father,generation-1);
        if(pig.mother != null)
            addAncerstry(ancestry,pig.mother,generation-1);
    }

    static class Pig{
        //  猪的标识
        private int selfId;
        //  猪它爸
        private Pig father;
        //  猪它妈
        private Pig mother;

        public Pig(int selfId, Pig father, Pig mother) {
            this.selfId = selfId;
            this.father = father;
            this.mother = mother;
        }

        @Override
        public String toString() {
            return "Pig{" +
                    "selfId=" + selfId +
                    ", father=" + father +
                    ", mother=" + mother +
                    '}';
        }

        public int getSelfId() {
            return selfId;
        }

        public void setSelfId(int selfId) {
            this.selfId = selfId;
        }

        public Pig getFather() {
            return father;
        }

        public void setFather(Pig father) {
            this.father = father;
        }

        public Pig getMother() {
            return mother;
        }

        public void setMother(Pig mother) {
            this.mother = mother;
        }
    }
}

从下往上，看，1的爸妈是2和3，2的爸妈是4和5

我现在可以通过猪的特定标识在数据库表中找到它的父母，后面应该要如何去实现这个四代比对过程呢？