使用UUID作为数据库主键，Java类型是一个字节[] [英] Using a UUID as a Database Primary Key, Java type is a byte[]

问题描述

在JPA实体中使用byte []作为主键是否存在任何问题?

Are there any issues with using a byte[] as a primary key in a JPA Entity?

我想使用UUID作为主键，但是存储为字符串，我觉得它太大了.

I want to use a UUID as my primary key, but stored as a string I feel it will be too large.

我当时正在考虑做这样的事情来将ID存储为字节[]并将其设置为我实体的ID:

I was thinking of doing something like this to store the ID as a byte[] and set it as my Entity's ID:

    public static byte[] byteArray(UUID uuid) {
        long lsb = uuid.getLeastSignificantBits();
        long msb = uuid.getMostSignificantBits();

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(bos);
        try {
            dos.writeLong(lsb);
            dos.writeLong(msb);
            dos.flush();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        byte[] data = bos.toByteArray();
//      System.out.println("Byte Array Length "+data.length);
        return data;

    }

在数据库中为此设置索引会遇到麻烦吗?我同时使用Postgres和HSQL.我正在使用Hibernate作为我的JPA提供程序.

Will I have any trouble putting indexes on this in the DB? I am using both Postgres and HSQL. I am using Hibernate as my JPA provider.

推荐答案

请记住，使用SQL客户端的用户在查询byte [] id时会遇到麻烦.这就是为什么数据库ID通常是数字的原因.手写查询要容易得多.

Bear in mind that users using an SQL client will have trouble querying for byte[] ids. That's why db ids are typically numbers; it's much easier to hand-write queries.

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