在MongoDB中插入或更新之前如何验证文档？
要验证文档，请使用验证概念。以下是查询-
> db.createCollection("demo356", {validator: {
... $and: [ {"FirstName": {$type: "string", $exists: true}} ]
... }})
{ "ok" : 1 }让我们创建一个包含文档的集合-
> db.demo356.insertOne({"FirstName":"Chris"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e568d49f8647eb59e5620c7")
}
> db.demo356.insertOne({"FirstName":909});
2020-02-26T20:52:58.497+0530 E QUERY [js] WriteError: Document failed validation :
WriteError({
"index" : 0,
"code" : 121,
"errmsg" : "Document failed validation",
"op" : {
"_id" : ObjectId("5e568d52f8647eb59e5620c8"),
"FirstName" : 909
}
})
WriteError@src/mongo/shell/bulk_api.js:461:48
Bulk/mergeBatchResults@src/mongo/shell/bulk_api.js:841:49
Bulk/executeBatch@src/mongo/shell/bulk_api.js:906:13
Bulk/this.execute@src/mongo/shell/bulk_api.js:1150:21
DBCollection.prototype.insertOne@src/mongo/shell/crud_api.js:252:9
@(shell):1:1在find()方法的帮助下显示集合中的所有文档-
> db.demo356.find();
这将产生以下输出-
{ "_id" : ObjectId("5e568d49f8647eb59e5620c7"), "FirstName" : "Chris" }