在MongoDB中按特定字段搜索
首先让我们创建一个包含文档的集合-
> db.demo371.insertOne({"Name":"David","CountryName":"US"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e57f6982ae06a1609a00af2")
}
> db.demo371.insertOne({"Name":"John","CountryName":"UK"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e57f69e2ae06a1609a00af3")
}
> db.demo371.insertOne({"Name":"Bob","CountryName":"AUS"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e57f6a42ae06a1609a00af4")
}
> db.demo371.insertOne({"Name":"Mike","CountryName":"US"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e57f6ba2ae06a1609a00af5")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo371.find();
这将产生以下输出-
{ "_id" : ObjectId("5e57f6982ae06a1609a00af2"), "Name" : "David", "CountryName" : "US" }
{ "_id" : ObjectId("5e57f69e2ae06a1609a00af3"), "Name" : "John", "CountryName" : "UK" }
{ "_id" : ObjectId("5e57f6a42ae06a1609a00af4"), "Name" : "Bob", "CountryName" : "AUS" }
{ "_id" : ObjectId("5e57f6ba2ae06a1609a00af5"), "Name" : "Mike", "CountryName" : "US" }以下是按特定字段搜索的查询-
> db.demo371.find({ $or: [ { Name: "David" }, { CountryName: "UK"} ] } )这将产生以下输出-
{ "_id" : ObjectId("5e57f6982ae06a1609a00af2"), "Name" : "David", "CountryName" : "US" }
{ "_id" : ObjectId("5e57f69e2ae06a1609a00af3"), "Name" : "John", "CountryName" : "UK" }