i have a few fields in my collection at the mongoDB.
i have tried exported out everything.
which looking like this
{"_id":{"$oid":"5a5ef05dbe83813f55141a51"},"comments_data":{"id":"211","comments":{"paging":{"cursors":{"after":"WzZANVFV4TlRVME5qUXpPUT09","before":"WTI5dEF4TlRVNE1USTVNemczTXpZAMk56YzZANVFV4TlRBMU9ERTFNQT09"}},"data":[{"created_time":"2018-01-04T09:29:09+0000","message":"Super","from":{"name":"M Mun","id":"1112"},"id":"1111"},{"created_time":"2018-01-07T22:25:08+0000","message":"Happy bday..Godbless you...","from":{"name":"L1","id":"111"},"id":"1111"},{"created_time":"2018-01-10T00:22:00+0000","message":"Nelson ","from":{"name":"Boon C","id":"1111"},"id":"10111"},{"created_time":"2018-01-10T01:07:19+0000","message":"Thank to SingTel I like to","from":{"name":"Sarkar WI","id":"411653482605703"},"id":"10155812413346677_10155825869201677"}]}},"post_id":"28011986676_10155812413346677","post_message":"\"Usher in the New Year with deals and rewards that will surely perk you up, exclusively for Singtel customers. Find out more at singtel.com/rewards\"",
but now i want to export just a single field which is the 'message' from the 'comments_data' from the collection.
i tried using this mongoexport --db sDB --collection sTest --fields data.comments_data --out test88.json
but when i check my exported file, it just contains something like this
{"_id":{"$oid":"5a5ef05dbe83813f55141a51"}}
which is something not i have expected.
i just want something like "message":"Happy bday..Godbless you..."
but when i query out at the mongoshell with db.sTest.find({}, {comments_data:1, _id:0})i can roughly get what i want.
If this ...
db.sTest.find({}, {'comments_data.message':1, _id:0})
... selects the data you are interested in then the equivalent mongoexport command is:
mongoexport --db sDB --collection sTest --fields 'comments_data.message' --type csv --out test88.csv
Note: this uses --type csv because, according to the docs, use of the JSON output format causes MongoDB to export all fields in the selected sub document ...
For csv output formats, mongoexport includes only the specified field(s), and the specified field(s) can be a field within a sub-document.
For JSON output formats, mongoexport includes only the specified field(s) and the _id field, and if the specified field(s) is a field within a sub-document, the mongoexport includes the sub-document with all its fields, not just the specified field within the document.
If you must have JSON format and limit your output to a single field then I think you'll need to write the reduced documents to a separate collection and export that collection, as per this answer.
Related
Let's say I want to insert an object that contains date objects using mongoimport from the commandline.
echo "{\"int_key\": 1, \"date_key\": new Date(\"2022-12-27\")}" | mongoimport --host "192.168.60.10" --db example_db --collection example_collection
will not work because the object I am trying to insert is not in the form of a valid JSON. The reason I want to use mongoimport is because there is an array of a large number of objects that I want to persist at one go. If I try to use the mongo command the argument length for --eval is too long. For example,
mongo --host "192.168.60.10" --eval "db=db.getSiblingDB(\"example_db\");db.getCollection(\"example_collection\").insert([{\"int_key\": 1, \"date_key\": new Date(\"2022-12-27\")}])"
but the array inside insert() has a very large number of objects. Can you suggest any workaround to this? I was thinking I could use mongoimport to read all the objects put into an array through stdin or a file. The options for using a json array would not allow the kind of array of objects I insert using the insert() in mongo --eval.
You have to use this
echo "{\"int_key\": 1, \"date_key\": {\"$date\": \"2022-12-27\"}}"
It may require:
echo "{\"int_key\": 1, \"date_key\": {\"\$date\": \"2022-12-27T00:00:00Z\"}}"
For other data types see MongoDB Extended JSON (v2)
I use mongoimport in the same way to insert around 6 billion documents per day, it is very fast and reliable.
Depending on how you use it, mongoimport does not import small amount of documents could be relevant for you.
I would like to import data to a MongoDb document from a .tsv file using the record _id as defined in my file.
How would I go about using the _id as specified in my .tsv, specifying the MongoDb should use the provided _id rather than generating its own?
Example data set:
student firstName lastName
ab867499 example student
I want MongoDb to use the student column as _id rather than generate its own object_id as the key.
Here is what you can do:
mongoimport --db <your_db_name> --collection <your_collection_name> --type tsv --file <path_to_file> --fields _id,firstName,lastName
In this case you will want to make sure that the first line of your file does not contain the header row or simply drop the imported document for the header row after the import.
Also, make sure you have a line break at the end of your last line of data in your file since mongoimport will skip this last record otherwise.
I am trying to export data to a CSV file but for some reason I am not getting any data in the CSV file.
I have a DB called "test", and a collection called "people". The contents of the people collection is (json export works!):
{"_id":{"$oid":"55937ce0c64ddad5023a9570"},"name":"Joe Bloggs","position":"CE"}
{"_id":{"$oid":"55937d57c64ddad5023a9571"},"name":"Jane Bloggs","position":"CE"}
{"_id":{"$oid":"55937d62c64ddad5023a9572"},"name":"Peter Smith","position":"CE"}
{"_id":{"$oid":"55937d78c64ddad5023a9573"},"name":"Sarah Smith","position":"STL"}
I am trying to export this data into a CSV file with the following command:
mongoexport --type=csv -d test -c people --fieldFile c:\dev\peopleFields.txt --out c:\dev\people.csv
When I run this command, the response is:
2015-07-01T14:56:36.787+0800 connected to: localhost
2015-07-01T14:56:36.787+0800 exported 4 records
The contents of peopleFields.txt is:
ID
Name
Position
And the resulting output to the people.csv file is:
ID,Name,Position
"","",""
"","",""
"","",""
"","",""
Could someone please explain to me what I am doing wrong?
What you are missing here is that the --fieldFile option is not a "mapping" but just a "list" of all the fields you want to export from the collection.
So to actually "match" fields present in your collection the content should be:
_id
name
position
Since the names you have do not match any fields, you get four lines ( one per document ) of blank field output, for the number of fields you specify.
The mongoexport utility itself will not "map" to alternate names. If you want different names to how they are stored in your collection then you will have to alter the output yourself.
The same goes for the output as any ObjectId value will be output as that literal string.
You can use following command to export data in csv file:
mongoexport --db dbName --collection collectionName --type=csv --fields name,position --out fileName.csv
As per documentation,
1) The fieldFile allows you to specify fields to include in the export.
2) The file must have only one field per line, and the line(s) must end with the LF character (0x0A).
You are using different name (ID, Name, Position) in text file as that of in collection (_id, name, position)so you are getting empty fields exported.
My MongoExport will pull three fields
--fields firstname,lastname,email,city
output:
firstname,lastname,email,city
"Fn1","Ln1","abc#abc.com","chicago"
"Fn2","Ln2","xyz#xyz.com","atlanta"
I want emails to be hidden so I need a hardcoded value 'EMAIL' instead of the actual email.
"Fn1","Ln1","EMAIL","chicago"
"Fn2","Ln2","EMAIL","atlanta"
Can this be done in mongo export?
I have over 100 fields and I am looking for a way so that I can just export the entire collection as CSV format
The command-line is asking to provide all fields via
-f [ --fields ] arg comma seperated list of field names e.g. -f
name,age
is there a way to get the entire collection like using dump but not in bson format?
I need CSV data
Thank you
In bash you can create this "export-all-collections-to-csv.sh" and pass the database name as the only argument (feel free to reduce this to a single collection):
OIFS=$IFS;
IFS=",";
dbname=$1 #put "database name" here if you don't want to pass it as an argument
collections=`mongo $dbname --eval "rs.slaveOk();db.getCollectionNames();" --quiet`;
collectionArray=($collections);
for ((i=0; i<${#collectionArray[#]}; ++i));
do
keys=`mongo $dbname --eval "rs.slaveOk();var keys = []; for(var key in db.${collectionArray[$i]}.findOne()) { keys.push(key); }; keys;" --quiet`;
mongoexport --db $dbname --collection ${collectionArray[$i]} --fields "$keys" --csv --out $dbname.${collectionArray[$i]}.csv;
done
IFS=$OIFS;
You could create a file with the field names (may be easier for you):
--fieldFile arg file with fields names - 1 per line
In your case they might all be the same but the reason you have to specify the field names is because they could be different for every document however the field names in the csv must be fixed.