MongoDB mongoengine（ODM）

# from mongoengine import *
from mongoengine import connect, Document, EmbeddedDocument, 
    StringField, IntField, FloatField, ListField, EmbeddedDocumentField

connect('students')   # 连接数据库

SEX_CHOISE = (       # 设置性别选项
    ('male', '男'),
    ('female', '女')
)


class Grade(EmbeddedDocument):
    """成绩"""
    name = StringField(required=True)
    score = FloatField(required=True)


class Student(Document):
    name = StringField(max_length=32, requiredd=True)
    age = IntField(required=True)
    sex = StringField(choices=SEX_CHOISE, required=True)
    grade = FloatField()
    address = StringField()
    grades = ListField(EmbeddedDocumentField(Grade))
    # remark = StringField()

    meta = {
        'collection': 'student',    # 设置集合名称
        'ordering': ['-age']        # 集合按年龄倒序
    }


class TestMongoEngine(object):

    def add_one(self):
        """添加一条数据"""
        yuwen = Grade(
            name='语文',
            score=90)
        shuxue = Grade(
            name='数学',
            score=100)
        stu_obj = Student(
            name='张三',
            age=15,
            sex='male',
            grades=[yuwen, shuxue]
        )
        # stu_obj.remark = 'remark'    必须在配置数据库时先定义，后续才可以添加
        stu_obj.save()
        return stu_obj

    def get_one(self):
        """查询一条数据"""
        return Student.objects.first()

    def get_more(self):
        """查询多条诗句"""
        # return Student.objects
        return Student.objects.all()

    def get_one_from_oid(self, oid):
        """查询指定ID的数据"""
        return Student.objects.filter(id=oid).first()    # 注意：根据id查询数据时一定要添加first()，不然报错或查不到数据

    def update(self):
        """修改数据"""
        # 修改一条数据
        # rest = Student.objects.filter(sex='male').update_one(inc__age=1)
        # return rest
        # 修改多条数据
        rest = Student.objects.filter(sex='male').update(inc__age=1)
        # 年龄增加1岁，文档：https://mongoengine-odm.readthedocs.io/guide/querying.html#advanced-queries
        # 查询条件（filter）里面可以增加gt__age=16表示年龄大于16岁，文档：https://mongoengine-odm.readthedocs.io/guide/querying.html#query-operators
        return rest

    def delete(self):
        """删除数据"""
        # 删除一条数据
        return Student.objects.filter(sex='male').first().delete()
        # 删除多条数据
        return Student.objects.filter(sex='male').delete()


def main():
    obj = TestMongoEngine()
    # rest = obj.add_one()
    # print(rest.id)

    # rest = obj.get_one()
    # print(rest.id, rest.name, rest.grades)

    # rest = obj.get_more()
    # for row in rest:
    #     print(row.name)

    rest = obj.get_one_from_oid("5e83f7e16490e7f8a4e4e284")
    if rest:
        print(rest.name)
    else:
        print("查询的数据不存在")

    # rest = obj.update()
    # for row in rest:
    #     print(row.age)

    # rest = obj.delete()
    # print(rest)   # 删除一条时返回None,删除多条是返回删除的数据条数


if __name__ == '__main__':
    main()