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  • 记一次MyBatisPlus问题(如果表名是数据库关键字怎么办)

    问题信息:
    如果表名是数据库关键字怎么办?

    正常来说,如果是我们自己写sql的话,给表名加反引号即可解决问题。

    但是由于我们使用MyBatisPlus,相关的sql基本上都是封装并自动生成的。如果是这种场景,我们就需要修改对应的实体,举例说明,如下代码:

    import com.baomidou.mybatisplus.enums.IdType;
    import com.baomidou.mybatisplus.annotations.TableId;
    import com.baomidou.mybatisplus.activerecord.Model;
    import java.io.Serializable;
    
    public class Group extends Model<Group> {
    
        private static final long serialVersionUID = 1L;
    
        /**
         * 组ID
         */
        @TableId(value = "id", type = IdType.AUTO)
        private Integer id;
        /**
         * 组名
         */
        private String name;
    
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        @Override
        protected Serializable pkVal() {
            return this.id;
        }
    
        @Override
        public String toString() {
            return "Group{" +
            "id=" + id +
            ", name=" + name +
            "}";
        }
    }

    用上述代码的自动生成肯定会有问题,以单条数据查询为例,默认是 select id,name from group where id = 1,又因为group属于关键字,接下来会出现如下错误信息:

    ### Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'group WHERE id=1' at line 1
    ; bad SQL grammar []; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'group WHERE id=1' at line 1] with root cause
    
    com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'group WHERE id=1' at line 1

    这种错误信息,很容易识别,一看就是sql写的有问题。但实际上sql并没有问题,只不过是因为关键字冲突导致sql错误。

    那么如何解决这个问题呢?
    答案是只需加一个@TableName注解即可解决该问题。修改后的实体代码如下:

    import com.baomidou.mybatisplus.enums.IdType;
    import com.baomidou.mybatisplus.annotations.TableId;
    import com.baomidou.mybatisplus.annotations.TableName;
    import com.baomidou.mybatisplus.activerecord.Model;
    import java.io.Serializable;
    
    
    @TableName("`group`")
    public class Group extends Model<Group> {
    
        private static final long serialVersionUID = 1L;
    
        /**
         * 组ID
         */
        @TableId(value = "id", type = IdType.AUTO)
        private Integer id;
        /**
         * 组名
         */
        private String name;
    
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        @Override
        protected Serializable pkVal() {
            return this.id;
        }
    
        @Override
        public String toString() {
            return "Group{" +
            "id=" + id +
            ", name=" + name +
            "}";
        }
    }
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  • 原文地址:https://www.cnblogs.com/youcong/p/11440653.html
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