There is a collection in my MongoDB that im not able to drop.
The name of the collection ends with a ` (backquote) character and I got error when executing the drop command.
db.MyCollection`.drop()
Error is
2017-12-07T07:42:35.711+0000 SyntaxError: Unexpected token ILLEGAL
Is there any other way of removing or is it here forever?
Just use getCollection function.
Example:
db.getCollection("MyCollection`").drop();
Related
I'm trying to use Query Variables in Grafana, the panel query source is PostgreSQL for QuestDB.
I have added the variable without any issue, but I'm unable to use the variable in Panel query since the variable values contains the spaces (SENSOR01 ON_OFF), also I'm unable to figure-out how to add single quote escape.
Following are the scenarios I tried:
Scenario1: this indicates due to space in the Variable value, on_off considered as separate word
where sensor_name = $sensor
db query error: pq: unexpected token: on_off
.
.
Scenario2: tried to add single quotes explicitly for the variable value, but there is generic error from source DB (QuestDB)
where sensor_name = concat('''', $sensor, '''')
db query error: pq: dangling expression
When tried Scenario2 approach directly in query of Variable, getting the same error
..
Scenario3: Hard-coded the variable value with space and with single quotes, but this giving me error with first part of the variable, looks like the hard-coded single quotes not passed here!
Error (Scenario3):
Is there any way/workaround to tackle this issue?
Could you just add the quotes directly in the query?
where sensor_name = '$sensor'
I have a similar grafana panel querying a questDB database using a variable and it works for me. This is my query:
select device_type, avg(duration_ms) as avg_duration_ms, avg(speed) as avg_speed, avg(measure1) as avg_m1, avg(measure2) as avg_m2 from ilp_test
WHERE
$__timeFilter(timestamp) and device_type = '$deviceType'
A rather hacky workaround would be to do:
where sensor_name = concat(cast(cast('&' as int) + 1 as char), $sensor, cast(cast('&' as int) + 1 as char))
This should work, but I'm pretty sure there is a better solution. Let me find it and get back to you.
Update. We may support Postgres syntax (which is '' escaping for a single quote char) in one of upcoming versions. For now, you'd have to use the above workaround.
I use a function insertOne to insert an object. I have place correct colon and also correct commas then why this error come. Thanks in Advance.
This is my code
db.items.insertOne({Name:"Oppo",Price:"45000",Ritems:"345",Sold:"45","Rating:"3.5",once"twos"})
Error is this
uncaught exception: SyntaxError: missing : after property id :
#(shell):1:78
>
I think that your "" are misplaced. I think this way would be better ??
db.items.insertOne({Name:"Oppo",Price:"45000",Ritems:"345",Sold:"45",Rating:"3.5",once:"twos"})
Also the error message is telling you about the Id column, you should check if you need to set it yourself or if your database has an auto-increment ID.
I created a collection named "stats" but whenever I try to delete it by using db.stats.drop() cmd line. It shows an error.
TypeError: db.stats.drop is not a function
Even tried this.
db["stats"].drop
Any solution?
if the collection exists db.stats.drop() should work (depending on the mongodb version maybe) or else perhaps db.getCollection("stats").drop();
but if all else fails, run: db.runCommand({drop : "stats"}) this should drop it if it exists without any error at least.
Can not delete the collection from the shell,
The thing that the collection is available and my php script is accessing it (selecting|updating)
But when I used:
db._registration.drop()
it gives me an error:
Date, JS Error: TypeErrorL db._registration has no properties (shell): 1
The problem is not with deleting the collection. The problem is with accessing the collection. So you would not be able to update, find or do anything with it from the shell. As it was pointed in mongodb JIRA, this is a bug when a collection has characters like _, - or .
Nevertheless this type of names for collections is acceptable, but it cause a problem in shell.
You can delete it in shell with this command:
db.getCollection("_registration").drop()
or this
db['my-collection'].drop()
but I would rather rename it (of course if it is possible and will not end up with a lot of changing).
You can also use:
db["_registration"].drop()
which syntax works in JS as well.
For some reason the double quotes "_registration" did not workfor me .. but single quote '_registration' worked
I have found a collection in one of our MongoDB databases with the name my.collection.
Is there a way to access this collection from the MongoDB shell, despite it having a point in the name?
> db.my.collection.findOne();
null
I'm pretty sure that that is not correct.
try this instead:
db["my.collection"].findOne();
you run into the same issue with hyphens or any other name that does not match on
[a-zA-Z_$][0-9a-zA-Z_$]
This limitation comes from valid named for javascript object properties.
if collection name is "my.collection"
db.my.collection.findOne(); // OK
null
if collection name is "my.1.collection"
db.my.1.collection.findOne(); // Not OK
SyntaxError: missing ; before statement
Fix:
db["my.1.collection"].findOne(); // Now is OK
null
Another foolproof method is:
db.getCollection("_SCHEMA").find()
While in the case of a underscore in the name, still cause a error with #Laura answer:
> db["_SCHEMA"].find()
2016-07-18T17:44:16.948+0200 E QUERY [thread1] TypeError: db._SCHEMA is undefined :
#(shell):1:1
Your code is correct. If it returns null it means that the collection is empty.