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Flask-SQLAlchemy精确查询&模糊查询---ORM(

Flask-SQLAlchemy精确查询&模糊查询---ORM(

作者: 忘了呼吸的那只猫 | 来源:发表于2019-07-29 15:39 被阅读0次

1.精确查询

  • 单条件–精确查询

from db_modules import Students
from flask_restful import reqparse, Resource


class StudentsAPI(Resource):
    def __init__(self):
        self.parser = reqparse.RequestParser()
        self.parser.add_argument("st_id", type=str)
        self.parser.add_argument("name", type=str)
        self.parser.add_argument("classID", type=str)
        self.parser.add_argument("remark", type=str)

    def get(self):
        args = self.parser.parse_args()

        key_st_id = args.st_id
        key_name = args.name
        key_classID = args.classID
        key_remark = args.remark

        all_results = Students.query.filter_by(classID=key_classID).all()

        data_list = list()
        if all_results:
            for i in all_results:
                dict_one = i.to_dict()
                print(dict_one, "--------")
                data_list.append(dict_one)

            value_msg = "success"
        else:
            value_msg = "couldn't search any infomation"

        result = {

            "status": 200,
            "msg": value_msg,
            "result": data_list

        }
        return result

输入的内容为:http://127.0.0.1:5000/student?classID=21

结果:
{
status: 200,
msg: "success",
result: [
            {
            classID: 21,
            gender: "1",
            st_id: 10001,
            remark: "小明是位可爱的孩子",
            age: 18,
            name: "小明"
            },
            {
            classID: 21,
            gender: "1",
            st_id: 10003,
            remark: "大牛是位勇敢的孩子",
            age: 19,
            name: "大牛"
            },
            {
            classID: 21,
            gender: "1",
            st_id: 10006,
            remark: "黑马王子",
            age: 22,
            name: "古天乐"
            }
        ]
}
  • 多条件–精确查询

# 将单条件中的查询代码改为下面的代码

all_results = Students.query.filter_by(classID=key_classID, name=key_name).all()

2.模糊查询

  • 1.单条件–模糊查询

from db_modules import Students
from flask_restful import reqparse, Resource


class StudentsAPI(Resource):
    def __init__(self):
        self.parser = reqparse.RequestParser()
        self.parser.add_argument("st_id", type=str)
        self.parser.add_argument("name", type=str)
        self.parser.add_argument("classID", type=str)
        self.parser.add_argument("remark", type=str)

    def get(self):
        args = self.parser.parse_args()

        key_st_id = args.st_id
        key_name = args.name
        key_classID = args.classID
        key_remark = args.remark

        all_results = Students.query.filter(
            Students.remark.like("%" + key_remark + "%") if key_remark is not None else ""
        ).all()

        data_list = list()
        if all_results:
            for i in all_results:
                dict_one = i.to_dict()
                print(dict_one, "--------")
                data_list.append(dict_one)

            value_msg = "success"
        else:
            value_msg = "couldn't search any infomation"

        result = {

            "status": 200,
            "msg": value_msg,
            "result": data_list

        }
        return result

浏览器输入:http://127.0.0.1:5000/student?remark=牛奶

结果:
{
    status: 200,
    msg: "success",
    result: [
                {
                classID: 22,
                gender: "1",
                st_id: 10007,
                remark: "不是所有牛奶都叫特仑苏",
                age: 23,
                name: "陈道明"
                }
    ]
}
  • 多条件–模糊查询

 all_results = Students.query.filter(
     Students.st_id.like("%" + key_st_id + "%") if key_st_id is not None else "",
     Students.name.like("%" + key_name + "%") if key_name is not None else "",
     Students.remark.like("%" + key_remark + "%") if key_remark is not None else "",
     Students.classID.like("%" + key_classID + "%") if key_classID is not None else ""
 ).all()

输入地址:http://127.0.0.1:5000/student?name=明

结果:
{
    status: 200,
    msg: "success",
    result: [
            {
                classID: 21,
                gender: "1",
                st_id: 10001,
                remark: "小明是位可爱的孩子",
                age: 18,
                name: "小明"
            },
            {
                classID: 22,
                gender: "1",
                st_id: 10007,
                remark: "不是所有牛奶都叫特仑苏",
                age: 23,
                name: "陈道明"
            }
            ]
}

3.精确 & 模糊混合查询

  • 先精确查询----再模糊查询


 all_results = Students.query.filter_by(classID = key_classID).filter(
     Students.st_id.like("%" + key_st_id + "%") if key_st_id is not None else "",
     Students.name.like("%" + key_name + "%") if key_name is not None else "",
     Students.remark.like("%" + key_remark + "%") if key_remark is not None else ""
 ).all()

输入地址:http://127.0.0.1:5000/student?name=明&classID=24

结果:
{
    status: 200,
    msg: "couldn't search any infomation",
    result: [ ]
}

输入地址:http://127.0.0.1:5000/student?name=明&classID=22

结果:
{
    status: 200,
    msg: "success",
    result: [
                {
                classID: 22,
                gender: "1",
                st_id: 10007,
                remark: "不是所有牛奶都叫特仑苏",
                age: 23,
                name: "陈道明"
                }
    ]
}
  • 多条件或查询(or_)


from sqlalchemy import or_   # 这个是需要额外导入的方法

all_results = Students.query.filter(
            or_(Students.st_id.like("%" + key_st_id + "%") if key_st_id is not None else "",
                Students.name.like("%" + key_name + "%") if key_name is not None else "",
                Students.remark.like("%" + key_remark + "%") if key_remark is not None else "",
                Students.classID.like("%" + key_classID + "%") if key_classID is not None else "")
        ).all()

浏览器输入:http://127.0.0.1:5000/student?name=花&st_id=10005&remark=牛奶
多个条件,每个条件单独满足即可,最终结果为所有集合的汇总

结果:
{
status: 200,
msg: "success",
result: [
            {
                classID: 22,
                gender: "0",
                st_id: 10004,
                remark: "花花是位懂事的孩子",
                age: 17,
                name: "花花"
            },
            {
                classID: 23,
                gender: "1",
                st_id: 10005,
                remark: "tony来自美国",
                age: 20,
                name: "tony"
            },
            {
                classID: 22,
                gender: "1",
                st_id: 10007,
                remark: "不是所有牛奶都叫特仑苏",
                age: 23,
                name: "陈道明"
            }
            ]
}
  • 多条件或查询(and_)


from sqlalchemy import and_   # 这个是需要额外导入的方法

all_results = Students.query.filter(
            and_(Students.st_id.like("%" + key_st_id + "%") if key_st_id is not None else "",
                Students.name.like("%" + key_name + "%") if key_name is not None else "",
                Students.remark.like("%" + key_remark + "%") if key_remark is not None else "",
                Students.classID.like("%" + key_classID + "%") if key_classID is not None else "")
        ).all()

这些基本的方法相互组合就可以满足一般情况,当然还有其他更复杂的功能,请参考文档,这里就不多做介绍。

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