一、后端实现

1、web层

定义删除api方法：CourseAdminController.java

@ApiOperation(value = "根据ID删除课程")
@DeleteMapping("{id}")
public R removeById(
    @ApiParam(name = "id", value = "课程ID", required = true)
    @PathVariable String id){

    boolean result = courseService.removeCourseById(id);
    if(result){
        return R.ok();
    }else{
        return R.error().message("删除失败");
    }
}

2、service层

如果用户确定删除，则首先删除video记录，然后删除chapter记录，最后删除Course记录

2.1、在VideoService中定义根据courseId删除video业务方法

接口

boolean removeByCourseId(String courseId);

实现

@Override
public boolean removeByCourseId(String courseId) {
    QueryWrapper<Video> queryWrapper = new QueryWrapper<>();
    queryWrapper.eq("course_id", courseId);
    Integer count = baseMapper.delete(queryWrapper);
    return null != count && count > 0;
}

*2.2、*在ChapterService中定义根据courseId删除chapter业务方法

接口

boolean removeByCourseId(String courseId);

实现

@Override
public boolean removeByCourseId(String courseId) {
    QueryWrapper<Chapter> queryWrapper = new QueryWrapper<>();
    queryWrapper.eq("course_id", courseId);
    Integer count = baseMapper.delete(queryWrapper);
    return null != count && count > 0;
}

*2.3、*删除当前course记录

接口：CourseService.java

boolean removeCourseById(String id);

实现：CourseServiceImpl.java

@Override
public boolean removeCourseById(String id) {

    //根据id删除所有视频
    videoService.removeByCourseId(id);

    //根据id删除所有章节
    chapterService.removeByCourseId(id);

    Integer result = baseMapper.deleteById(id);
    return null != result && result > 0;
}

二、前端实现

1、定义api

course.js中添加删除方法

removeById(id) {
    return request({
        url: `${api_name}/${id}`,
        method: 'delete'
    })
}

2、修改删除按钮

src/api/edu/course.js 删除按钮注册click事件

<el-button type="text" size="mini" icon="el-icon-delete" @click="removeDataById(scope.row.id)">删除</el-button>

3、编写删除方法

removeDataById(id) {
    // debugger
    this.$confirm('此操作将永久删除该课程，以及该课程下的章节和视频，是否继续?', '提示', {
        confirmButtonText: '确定',
        cancelButtonText: '取消',
        type: 'warning'
    }).then(() => {
        return course.removeById(id)
    }).then(() => {
        this.fetchData()
        this.$message({
            type: 'success',
            message: '删除成功!'
        })
    }).catch((response) => { // 失败
        if (response === 'cancel') {
            this.$message({
                type: 'info',
                message: '已取消删除'
            })
        }
    })
}