MongoDB `$nor` 运算符 (`$nor`)

MongoDB 提供了各种逻辑查询运算符。$nor 运算符是其中之一。$nor 运算符用于在一个或多个表达式的数组上执行逻辑的 “NOR 操作”。换句话说，$nor 是一个逻辑查询运算符，它允许用户在一个或多个查询表达式的数组上执行逻辑的 NOR 操作。此运算符还用于选择或检索与数组中的所有给定表达式不匹配的文档。用户可以根据自己的需求在find()、update()等方法中使用此运算符。

语法

{ $nor: [ { Expression1 }, { Expression2 }, ... { ExpressionN } ] }

示例

在以下示例中，我们正在使用：

Database: JavaTpoint
Collection: student
Document: Five documents that contain the details of the students

>db.student.find()
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d65f"),
           "name" : "Mick",
           "Course" : "btech",
           "batch_year" : 2018,
           "language" : ["c++", "java", "python"],
           "personal_details" : 
                     {
                      "Father_name" : "Jonny",
                      "phone_no" : 8895321456,
                      "age" : 23,
                      "gender" : "Male",
                      "City" : "NewYork",
                     }            
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d691"),
           "name" : "Zoya",
           "Course" : "BCA",
           "batch_year" : 2020,
           "language" : ["C#", "JavaScript"],
           "personal_details" : 
                     {
                      "Father_name" : "Henry",
                      "phone_no" : 9874563698,
                      "age" : 20,
                      "gender" : "Female",
                      "City" : "London",
                     }
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d655"),
           "name" : "Jonny",
           "Course" : "MCA",
           "batch_year" : 2019,
           "language" : ["C#", "java", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "Thomas",
                      "phone_no" : 7845123698,
                      "age" : 24,
                      "gender" : "Male",
                      "City" : "London",
                     }          
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d678"),
           "name" : "Oliver",
           "Course" : "BA",
           "batch_year" : 2017,
           "language" : ["c", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "William",
                      "phone_no" : 9997845123,
                      "age" : 25,
                      "gender" : "Male",
                      "City" : "Liverpool",
                     }           
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d665"),
           "name" : "Mia",
           "Course" : "btech",
           "batch_year" : 2020,
           "language" : ["HTML", "CSS", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "Leo",
                      "phone_no" : 6312547896,
                      "age" : 22,
                      "gender" : "Female",
                      "City" : "Manchester",
                     }           
}

示例1：使用`$nor`运算符匹配值

在这个示例中，我们只检索那些课程不是btech的学生的数据。

>db.student.find({$nor: [{Course: "btech"}]}).pretty()

输出：

>db.student.find({$nor: [{Course: "btech"}]}).pretty()
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d691"),
           "name" : "Zoya",
           "Course" : "BCA",
           "batch_year" : 2020,
           "language" : ["C#", "JavaScript"],
           "personal_details" : 
                     {
                      "Father_name" : "Henry",
                      "phone_no" : 9874563698,
                      "age" : 20,
                      "gender" : "Female",
                      "City" : "London",
                     }
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d655"),
           "name" : "Jonny",
           "Course" : "MCA",
           "batch_year" : 2019,
           "language" : ["C#", "java", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "Thomas",
                      "phone_no" : 7845123698,
                      "age" : 24,
                      "gender" : "Male",
                      "City" : "London",
                     }          
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d678"),
           "name" : "Oliver",
           "Course" : "BA",
           "batch_year" : 2017,
           "language" : ["c", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "William",
                      "phone_no" : 9997845123,
                      "age" : 25,
                      "gender" : "Male",
                      "City" : "Liverpool",
                     }           
}

MongoDB <code>$nor</code> 运算符 (<code>$nor</code>)” title=”MongoDB <code>$nor</code> 运算符 (<code>$nor</code>)” /></p>
<h3>示例2：使用$nor运算符匹配两个值</h3>
<p>在这个示例中，我们只检索那些课程不是btech且批次年份不是2017年的学生的数据。</p>
<pre><code class= >db.student.find({$nor: [{Course: "btech"}, {batch_year: "2017"}]}).pretty()

输出：

>db.student.find({$nor: [{Course: "btech"}, {batch_year: "2017"}]}).pretty()
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d691"),
           "name" : "Zoya",
           "Course" : "BCA",
           "batch_year" : 2020,
           "language" : ["C#", "JavaScript"],
           "personal_details" : 
                     {
                      "Father_name" : "Henry",
                      "phone_no" : 9874563698,
                      "age" : 20,
                      "gender" : "Female",
                      "City" : "London",
                     }
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d655"),
           "name" : "Jonny",
           "Course" : "MCA",
           "batch_year" : 2019,
           "language" : ["C#", "java", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "Thomas",
                      "phone_no" : 7845123698,
                      "age" : 24,
                      "gender" : "Male",
                      "City" : "London",
                     }          
}

示例3：使用$nor运算符匹配数组中的值

在这个示例中，我们只检索不匹配给定数组的学生数据。

> db.student.find({ $nor: [{language: {$ in: ["Java", "C#"]}}]}).pretty()

输出：

> db.student.find({ $nor: [{language: {$ in: ["Java", "C#"]}}]}).pretty()
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d678"),
           "name" : "Oliver",
           "Course" : "BA",
           "batch_year" : 2017,
           "language" : ["c", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "William",
                      "phone_no" : 9997845123,
                      "age" : 25,
                      "gender" : "Male",
                      "City" : "Liverpool",
                     }           
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d665"),
           "name" : "Mia",
           "Course" : "btech",
           "batch_year" : 2020,
           "language" : ["HTML", "CSS", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "Leo",
                      "phone_no" : 6312547896,
                      "age" : 22,
                      "gender" : "Female",
                      "City" : "Manchester",
                     }           
}

示例4：MongoDB逻辑$nor运算符（检索嵌入文档中的数据）

在这个示例中，我们只获取城市不是“伦敦”并且年龄不是22岁的学生的数据。

>db.student.find({$nor: [{"personal.age": 22}, {"personal.city": "London"}]}).pretty()

输出：

>db.student.find({$nor: [{"personal.age": 22}, {"personal.city": "London"}]}).pretty()
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d65f"),
           "name" : "Mick",
           "Course" : "btech",
           "batch_year" : 2018,
           "language" : ["c++", "java", "python"],
           "personal_details" : 
                     {
                      "Father_name" : "Jonny",
                      "phone_no" : 8895321456,
                      "age" : 23,
                      "gender" : "Male",
                      "City" : "NewYork",
                     }            
}
{
           "_id" : ObjectId("56254d4fdf2222265r4g12ds3d678"),
           "name" : "Oliver",
           "Course" : "BA",
           "batch_year" : 2017,
           "language" : ["c", "PHP"],
           "personal_details" : 
                     {
                      "Father_name" : "William",
                      "phone_no" : 9997845123,
                      "age" : 25,
                      "gender" : "Male",
                      "City" : "Liverpool",
                     }           
}