这里记录一个查询需求:数据库中字段的值(数组类型)都在指定的数组中。举例说一下实际场景,数据库中一个字段存储用户“可以使用的编程语言”,一般都会是多个,所以该字段是数组格式。现在要查询的是:会c#、javascript或者只会c#或者只会javascript的用户,翻译一下就是数据库中字段的值是子集而给定的数组是全集。这种查询需要在mongodb没有找到特定的查询操作符,这篇笔记主要解决这个问题,顺便介绍一下"$all"运算符。"$all"查询的是数据库字段的值包含所有指定元素的数组,也就是数据库中字段的值是全集而给定的数组是子集,和前面提到的需求相反。
为了演示上述的两种查询需求,先造一些测试数据,下面是表结构:
编程语言调查表(FormId: 507048044944694000, FormVersion: 507048044944694001) |
||||
唯一标识 |
中文描述 |
控件类型 |
是否必填 |
表单项的其他配置(在表单设计时配置,文本框长度、时间格式等) |
1572493554001 |
用户 |
选择人员控件 |
是 |
|
1572493554002 |
可以使用的编程语言 |
复选框 |
否 |
|
1572493554003 |
最喜欢的编程语言 |
文本框 |
否 |
|
1572493554004 |
工作地点 |
文本框 |
否 |
|
1572493554005 |
工作年限 |
数值输入框 |
否 |
|
1572493554006 |
备注 |
多行文本框 |
否 |
下面是造数据的语句
var GV_TableName = "FormInstace",
GV_FormId = "507048044944694000",
GV_FormVersion = "507048044944694001",
GV_CreateUserIds = ["user10000", "user10001", "user10002", "user10003", "user10004", "user10005", "user10006", "user10007", "user10008", "user10009"];
var GV_LangObj = {
1: {
id: "1",
text: "C#"
},
2: {
id: "2",
text: "JavaScript"
},
3: {
id: "3",
text: "HTML"
},
4: {
id: "4",
text: "CSS"
},
5: {
id: "5",
text: "Go"
},
6: {
id: "6",
text: "Rust"
}
};
var GV_Name2Id = {
"userName": "1572493554001",
"lang": "1572493554002",
"favLang": "1572493554003",
"workPlace": "1572493554004",
"workYears": "1572493554005",
"remarks": "1572493554006",
};
var getGUID = function () {
return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function (c) {
var r = Math.random() * 16 | 0,
v = c == "x" ? r : (r & 0x3 | 0x8);
return v.toString(16).toUpperCase();
});
}
var getFormInstanceOtherAttrs = function (formId, formVersion) {
var tempCreateUserIdIndex = Math.floor(Math.random() * GV_CreateUserIds.length),
tempCreateDate = ISODate();
return {
_id: getGUID(),
ExtendData: {},
CreateUserId: GV_CreateUserIds[tempCreateUserIdIndex],
CreateUserName: GV_CreateUserIds[tempCreateUserIdIndex],
CreateDate: tempCreateDate,
LastModifyDate: tempCreateDate,
FormId: GV_FormId,
FormVersion: GV_FormVersion
};
};
var assembleFormInstance = function (formItemsAttr) {
return Object.assign(formItemsAttr, getFormInstanceOtherAttrs());
}
//************************************************************************************************************************************************
// 批量插入数据
db[GV_TableName].insertMany([
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u1"
}, {
key: GV_Name2Id.lang,
value: [GV_LangObj["1"], GV_LangObj["2"], GV_LangObj["3"], GV_LangObj["4"]]
}, {
key: GV_Name2Id.favLang,
value: [GV_LangObj["1"]]
}, {
key: GV_Name2Id.workPlace,
value: "北京"
}, {
key: GV_Name2Id.workYears,
value: 1
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u2"
}, {
key: GV_Name2Id.lang,
value: [GV_LangObj["1"], GV_LangObj["2"], GV_LangObj["6"]]
}, {
key: GV_Name2Id.favLang,
value: [GV_LangObj["6"]]
}, {
key: GV_Name2Id.workPlace,
value: "天津"
}, {
key: GV_Name2Id.workYears,
value: 2
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u3"
}, {
key: GV_Name2Id.lang,
value: [GV_LangObj["1"], GV_LangObj["2"]]
}, {
key: GV_Name2Id.favLang,
value: [GV_LangObj["1"]]
}, {
key: GV_Name2Id.workPlace,
value: "石家庄"
}, {
key: GV_Name2Id.workYears,
value: 3
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u4"
}, {
key: GV_Name2Id.lang,
value: [GV_LangObj["1"], GV_LangObj["5"]]
}, {
key: GV_Name2Id.favLang,
value: [GV_LangObj["5"]]
}, {
key: GV_Name2Id.workPlace,
value: "上海"
}, {
key: GV_Name2Id.workYears,
value: 4
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u5"
}, {
key: GV_Name2Id.lang,
value: [GV_LangObj["1"]]
}, {
key: GV_Name2Id.favLang,
value: [GV_LangObj["1"]]
}, {
key: GV_Name2Id.workPlace,
value: "广州"
}, {
key: GV_Name2Id.workYears,
value: 5
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u6"
}, {
key: GV_Name2Id.lang,
value: [GV_LangObj["2"]]
}, {
key: GV_Name2Id.favLang,
value: [GV_LangObj["2"]]
}, {
key: GV_Name2Id.workPlace,
value: "深圳"
}, {
key: GV_Name2Id.workYears,
value: 6
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u7"
}, {
key: GV_Name2Id.lang,
value: []
}, {
key: GV_Name2Id.favLang,
value: []
}, {
key: GV_Name2Id.workPlace,
value: "成都"
}, {
key: GV_Name2Id.workYears,
value: 7
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
assembleFormInstance({
FormItems: [{
key: GV_Name2Id.userName,
value: "u8"
}, {
key: GV_Name2Id.lang,
value: [GV_LangObj["5"], GV_LangObj["6"]]
}, {
key: GV_Name2Id.favLang,
value: [GV_LangObj["5"]]
}, {
key: GV_Name2Id.workPlace,
value: "重庆"
}, {
key: GV_Name2Id.workYears,
value: 8
}, {
key: GV_Name2Id.remarks,
value: "随便写点什么"
}
]
}),
]);
View Code
看一下插入的数据:
这里数据结构和之前表单生成器(Form Builder)之表单数据存储结构mongodb篇文章中介绍的一样。为了方便查看,将“可以使用的编程语言”字段从“FormItems”数组中拿出来并放在最外层,下面是语句
// 通用聚合管道(将“编程语言”表单项从"FormItems"中拷贝一份放到最外层,方便查看)
var showLangItemPrePipeline = [{
$addFields: {
FormItemObj: {
$arrayToObject: {
$map: {
input: "$FormItems",
as: "field",
in: [
"$$field.key",
"$$field.value"
]
}
}
}
}
}, {
$addFields: {
"LangFormItem": "$FormItemObj.1572493554002",
}
}, {
$addFields: {
"1572493554002": {
$reduce: {
input: "$LangFormItem",
initialValue: "",
in: {
$concat: ["$$value", "$$this.text", ","]
}
}
},
}
}, {
$project: {
"FormItemObj": 0,
"LangFormItem": 0
}
}
];
// 1、查询:展示一下插入的示例数据
db.getCollection("FormInstace").aggregate(showLangItemPrePipeline);
下面看一下查询效果:
说明:从制造假数据的语句中你可以看到“1572493554002”字段是数组类型并且每一项都是一个对象,上图中将数组拼接成了字符串,方便查看。
先来看一下数据库中字段的值都在指定元素的数组中的查询语句:
// 通用聚合管道(将“编程语言”表单项从"FormItems"中拷贝一份放到最外层,方便查看)
var showLangItemPrePipeline = [{
$addFields: {
FormItemObj: {
$arrayToObject: {
$map: {
input: "$FormItems",
as: "field",
in: [
"$$field.key",
"$$field.value"
]
}
}
}
}
}, {
$addFields: {
"LangFormItem": "$FormItemObj.1572493554002",
}
}, {
$addFields: {
"1572493554002": {
$reduce: {
input: "$LangFormItem",
initialValue: "",
in: {
$concat: ["$$value", "$$this.text", ","]
}
}
},
}
}, {
$project: {
"FormItemObj": 0,
"LangFormItem": 0
}
}
];
db.getCollection("FormInstace").aggregate(showLangItemPrePipeline.concat([{
"$match": {
"FormId": "507048044944694000",
"FormItems": {
"$elemMatch": {
"key": "1572493554002",
"value.0": {
"$exists": true
},
"value": {
"$not": {
"$elemMatch": {
"text": {
"$nin": ["C#", "JavaScript"]
}
}
}
}
}
}
}
}
]))
来一张截图,看一下查询结果:
注意:这里语句中还用到了“$exists”运算符,如果不添加这个会将数组长度为0的查出来。参考链接。
在看一下“$all”查询,数据库字段的值包含所有指定元素的数组:
// 通用聚合管道(将“编程语言”表单项从"FormItems"中拷贝一份放到最外层,方便查看)
var showLangItemPrePipeline = [{
$addFields: {
FormItemObj: {
$arrayToObject: {
$map: {
input: "$FormItems",
as: "field",
in: [
"$$field.key",
"$$field.value"
]
}
}
}
}
}, {
$addFields: {
"LangFormItem": "$FormItemObj.1572493554002",
}
}, {
$addFields: {
"1572493554002": {
$reduce: {
input: "$LangFormItem",
initialValue: "",
in: {
$concat: ["$$value", "$$this.text", ","]
}
}
},
}
}, {
$project: {
"FormItemObj": 0,
"LangFormItem": 0
}
}
];
db.getCollection("FormInstace").aggregate(showLangItemPrePipeline.concat([{
"$match": {
"FormId": "507048044944694000",
"FormItems": {
"$elemMatch": {
"key": "1572493554002",
"value.text": {
"$all": ["C#", "JavaScript"]
}
}
}
}
}
]))
来一张截图,看一下查询结果:
这里在顺便记录一下在mongodb中数值转字符串,高版本有“$toString”操作符(版本4.0)、“$convert”操作符(版本4.0)……但是低版本的该如何处理,参考链接。这个例子比较简单,就不写制造数据的语句了,直接来查询语句:
db.getCollection("test001").aggregate([
{
$addFields: {
"ageStr": { $substr: [ "$num", 0, -1 ] }
}
}
])
来一张截图,看一下查询结果: