Missing before statement MongoDB

In this MongoDB tutorial, I will explain how I managed to resolve the error “Missing before statement MongoDB”. We will also cover multiple examples to understand the reason behind getting errors and resolve the error.

Don’t worry if you don’t know how to resolve these issues. In the below steps, we will discuss the reason for getting the error and also resolve the error.

The error could look like this;

• Missing before statement MongoDB
• SyntaxError missing before statement @(shell) mongodb
• SyntaxError: missing ) after argument list

These are the following topics that we cover in this article:

• Reason: Missing before statement MongoDB
• Solution: Missing before statement MongoDB with Examples
• Conclusion

Reason: Missing before statement MongoDB

We use the MongoDB shell for the execution of the MongoDB query. We can also use the GUI tool of MongoDB that is the MongoDB Compass for the execution.

The reason behind getting errors is when we are executing any query or command of MongoDB, we forget the following things and that is why an error comes.

Any of these could be the reason for the error

• The collection names should begin with an underscore or a letter corrector.
• Check you closed the bracket if you have used any in the syntax
• Check you closed the quotes or not if any used
• Execute MongoDB command on the correct place

Solution: Missing before statement MongoDB with Examples

We will troubleshoot this error “Missing before statement MongoDB” with the help of the following examples.

In the examples, you will see how the error occurred and what will be the solution to the error.

Examples:

Error 1: An error occurs due to bracket

In this example, we insert some documents into the data collection.

db.data.insertMany([
{ "_id" : 1, "House" : "102 1st street", "City" : "LA" },
{ "_id" : 2, "House" : "272 Quark street", "City" : "Canada" },
{ "_id" : 3, "House" : "206 2nd street", "City" : "LA" },
{ "_id" : 4, "House" : "500 5th street", "City" : "LA" }
])

Now, we insert a new document into the data collection.

> db.data.insert( _id: 5, House: "Quark street", City: "Canada" )

After executing this code, we got the error and the reason behind getting the error is we didn’t provide curly bracket “{ }“. See the executing of the code below.

Right the code to insert documents into collections is given below.

db.data.insert({ _id: 5, House: "Quark street", City: "Canada" })

The reason for using “{ }” is storing the data in JSON format like an array of one or more documents to insert into the named collection.

After inserting the document into the data collection:

> db.data.find().pretty()
{ "_id" : 1, "House" : "102 1st street", "City" : "LA" }
{ "_id" : 2, "House" : "272 Quark street", "City" : "Canada" }
{ "_id" : 3, "House" : "206 2nd street", "City" : "LA" }
{ "_id" : 4, "House" : "500 5th street", "City" : "LA" }
{ "_id" : 5, "House" : "Quark street", "City" : "Canada" }

Here, find() is used to select documents in a collection and return a cursor to the selected documents.

Error 2: The error occurs due to bracket

In this example, The following documents were inserted into the movies collection

db.movies.insertMany([
{"_id": 1, "name": "HarryPotter", "type": "fiction", "rating": "A"},
{"_id": 2, "name": "LOTR", "rating": "C", "type" : "fiction"},
{"_id": 3, "name": "Witchcraft", "type": "horror", "rating": "A"},
{"_id": 4, "name": "panda", "type": "romance", "rating": "A"},
{"_id": 5, "name": "What is new", "type": "comedy", "rating": "A"},
{"_id": 6, "name": "Date", "type": "romance", "rating": "D" }
])

Now when we were retrieving the documents of the movies collection with the help of the find() method got the below error.

Here, this error occurred because we didn’t specify the round bracket “( )” in the find() method. So that is the only reason you are getting errors.

Now, use the below code to access the documents of the collection;

db.movies.find().pretty()

Note that, when you execute any command of MongoDB cross-check that code or command so that this kind of basic error does not occur.

Error 3: Collection name can not be number

In this example, we are inserting a document into the 786 collections.

 db.786.insert({ Name: "Bob", Age: 21, Gender: "Male" })

Here, the error occurred because we use the collection name as a number. Always remember that the collection names should begin with an underscore or a letter corrector. Consider the below example:

> db.A786.insert({ Name: "Bob", Age: 21, Gender: "Male" })
WriteResult({ "nInserted" : 1 })

Here, we took the collection name as A786 and successfully inserted the document without any error fall.

Error 4: Error during the execution of mongoexport command

The mongoexport is used to export MongoDB collection data to a CSV or JSON file.  The mongoexport commands connect to the mongod instance running on the localhost port number 27017.

In this example, we got the error while executing the below command in the MongoDB shell.

mongoexport --db test --collection movies --out E:/Practice/movies.json

Here, we are exporting the movies collection into the movies.json file.

The mongoexport must be run from the OS command shell, not in the mongo shell. See the execution of code in the OS command shell

After executing the command in the OS command shell, the error will be resolved and we successfully exported the documents into a JSON file.

Conclusion

The error “Missing before statement MongoDB” indicates that there is a problem with the syntax. This is generally caused when we didn’t write the correct query so always check the query before the execution.

Thus, you might have learned the cause and the solution of the error “Missing before statement MongoDB ”.

• Reason: Missing before statement MongoDB
• Solution: Missing before statement MongoDB with Example
• Conclusion

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