spring data jpa指定联合索引

　　如何，现在我的表里使用订单ID和产品ID作为唯一索引，那么需要在定义表实体类时在@Table中指定UniqueConstraint：

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import javax.persistence.*;

/**
 * 产品表
 *
 * @author wulinfeng
 * @since 2019/12/13
 */
@Entity
@Table(name = "t_product", uniqueConstraints = @UniqueConstraint(columnNames = {"orderId", "productId"}))
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class ProductItem {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    // 订单Id
    @Column(nullable = false, length = 32)
    private String orderId;

    // 受理产品编码
    @Column(length = 32)
    private String productId;

    // 产品名称
    @Column(length = 32)
    private String productName;

    // 时间戳
    @Column(length = 13)
    private Long timestamp;
}

　　把原来的t_product表drop掉，重启spring boot，再看该表，自动加上唯一索引了：

mysql> show index from t_product;
+-----------+------------+-----------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table     | Non_unique | Key_name                    | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-----------+------------+-----------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| t_product |          0 | PRIMARY                     |            1 | id          | A         |           2 |     NULL | NULL   |      | BTREE      |         |               |
| t_product |          0 | UK1mvw2lcd07t4cuicl4awfbgkw |            1 | order_id    | A         |           2 |     NULL | NULL   |      | BTREE      |         |               |
| t_product |          0 | UK1mvw2lcd07t4cuicl4awfbgkw |            2 | product_id  | A         |           2 |     NULL | NULL   | YES  | BTREE      |         |               |
+-----------+------------+-----------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
3 rows in set (0.00 sec)