I am relatively new to mongoDb in python, so kindly help
I have created a collection called waste:
class Waste(Document):
meta = {'collection': 'Waste'}
item_id = IntField(required=True)
date_time_record = DateTimeField(default=datetime.utcnow)
waste_id = IntField(unique=True, required=True)
weight = FloatField(required= True)
I want to do a range query for a given start and end date:
I have tried the following query:
start = datetime(start_year, start_month, start_day)
end = datetime(end_year, end_month, end_day)
kwargs['date_time_record'] = {'$lte': end, '$gte': start}
reports = Waste.objects(**kwargs).get()
But I keep getting the error: DoesNotExist: Waste matching query does not exist.
the date value being sent as:
{
"start_year": 2020,
"start_month" : 5,
"start_day" : 10,
"end_year": 2020,
"end_month" : 5,
"end_day" : 20
}
when I try to get the first object from the collection, the output in json is:
{"_id": {"$oid": "5ebbcf126fdbb9db9f74d24a"}, "item_id": 96387295, "date_time_record": {"$date": 1589366546870}, "waste_id": 24764942, "weight": 32546.0}
a $date is added and I am unable to decipher the numbers in the date field. But when I look at the data using the mongo compass it looks just fine:
There exist a record in the given date range so I am unable to understand where am I going wrong.
I got this working by using Q:
the query I used is
reports = Waste.objects((Q(date_time_record__gte=start) & Q(date_time_record__lte=end)))
The response is:
[{"_id": {"$oid": "5ebbcf126fdbb9db9f74d24a"}, "item_id": 96387295, "date_time_record": {"$date": 1589366546870}, "waste_id": 24764942, "weight": 32546.0}]
I want to update the value of Entry1 using upsert. I have a sensor that returns the value of Entry1. If sensor is blocked, the value is true. If sensor is not blocked then the value is False.
machineOne = None
oneIn = 1
while True:
global machineOneId
global userId
try:
if Entry1.get_value() and oneIn < 2:
machineOne = Entry1.get_value()
print('entered looopp ONeeeE', machineOne)
machine1 = {
'Entry1': Entry1.get_value(),
'Exit1': Exit1.get_value(),
'id': 'test'
}
result = Machine1.insert_one(machine1)
myquery = {"Entry1": 'true'}
newvalues = {"$set": {"id": result.inserted_id}}
#result = Machine1.insert_one(machine1)
Machine1.update_one(myquery, newvalues)
userId = result.inserted_id
oneIn += 1
print('added', result.inserted_id, oneIn)
elif machineOne:
print('entered looopp', userId)
myquery = {"id": userId}
newvalues = {"$set": {"id": Entry1.get_value()}}
upsert = True
#result = Machine1.insert_one(machine1)
Machine1.update_one(myquery, newvalues)
if Exit1.get_value():
print('added',)
finally:
print('nothings happened', machineOne)
what is expected: i should be able to update the Entry1 from true to false in the same log, displayed in robo3t
Good Afternoon #digs10 ,
I read your post and I think the error is how you locate the document that you want to update.
I remember that MongoDB document primary key is "_id" instead of "id". You could take a look here MongoDB Documents
For what I see in the code (I don't know Python but it is readable), you are referring to the document "Entry1" using the field "id" instead of "_id.
Try modifing the line myquery = {"id": userId} for myquery = {"_id": userId}.
I hope this answer can help you.
Best Regards,
JB
P.S: I saw this question in my email and I took a quick read of it, If I misunderstood it, please let me know.
I have following document in MongoDB 3.6
forum_collection = { '_id' : id,
'tags': tags,
'sub_topic_name' : sub_topic_name,
'topic_creator' : creator_name,
'main_forum_name' : forum_name,
'threads' : [ {'thread_id' = uuid4,
'thread_title = title,
'thread_author = author,
'thread_comment_cout = 0,
'thread_body' = content,
'thread_comments' = [ {'thread_comment_id' : uuid4,
'thread_comment_body': content,
'thread_commenter' : author,
'thread_comment_time' : time
},
]
'thread_time' = time,
},
],
SO I want to have forum_collection with multiple sub_topics, each sub_topics have threads and each thread have comments.
How can I add a new sub comment and update the thread_comment_count to 1 ? My following attempt fails miserably...my function passes three variables, sub_topic (to query the sub_topic_name), thread (to query thread_id) and thread_vals (to append new comment to thread_id)
forum_collection.find_one_and_update({'sub_topic_name': sub_topic, 'threads.thread_id' : thread},
{'$inc': {'threads.'+thread+'.thread_comments_count': 1},
'$addToSet': {thread + '.threads_comment': thread_vals}},
return_document=pymongo.ReturnDocument.AFTER
)
How does it fail?
I don't know if it was a copy/paste error but your "thread_comment_cout is misspelled .
Also the $addToSet should refer to "threads" not "thread"
I needed to add $ at appropriate places....so not 'threads.'+thread+'.thread_comments_count' but 'threads.$.thread_comments_count'...
forum_collection.find_one_and_update({'sub_topic_name': sub_topic, 'threads.thread_id' : thread},
{'$inc': {'threads.$.thread_comments_count': 1},
'$addToSet': {'threads.$.thread_comments': thread_vals}},
return_document=pymongo.ReturnDocument.AFTER
)
Following the documentation, I'm trying to create an update statement that will update or add if not exists only one attribute in a dynamodb table.
I'm trying this
response = table.update_item(
Key={'ReleaseNumber': '1.0.179'},
UpdateExpression='SET',
ConditionExpression='Attr(\'ReleaseNumber\').eq(\'1.0.179\')',
ExpressionAttributeNames={'attr1': 'val1'},
ExpressionAttributeValues={'val1': 'false'}
)
The error I'm getting is:
botocore.exceptions.ClientError: An error occurred (ValidationException) when calling the UpdateItem operation: ExpressionAttributeNames contains invalid key: Syntax error; key: "attr1"
If anyone has done anything similar to what I'm trying to achieve please share example.
Found working example here, very important to list as Keys all the indexes of the table, this will require additional query before update, but it works.
response = table.update_item(
Key={
'ReleaseNumber': releaseNumber,
'Timestamp': result[0]['Timestamp']
},
UpdateExpression="set Sanity = :r",
ExpressionAttributeValues={
':r': 'false',
},
ReturnValues="UPDATED_NEW"
)
Details on dynamodb updates using boto3 seem incredibly sparse online, so I'm hoping these alternative solutions are useful.
get / put
import boto3
table = boto3.resource('dynamodb').Table('my_table')
# get item
response = table.get_item(Key={'pkey': 'asdf12345'})
item = response['Item']
# update
item['status'] = 'complete'
# put (idempotent)
table.put_item(Item=item)
actual update
import boto3
table = boto3.resource('dynamodb').Table('my_table')
table.update_item(
Key={'pkey': 'asdf12345'},
AttributeUpdates={
'status': 'complete',
},
)
If you don't want to check parameter by parameter for the update I wrote a cool function that would return the needed parameters to perform a update_item method using boto3.
def get_update_params(body):
"""Given a dictionary we generate an update expression and a dict of values
to update a dynamodb table.
Params:
body (dict): Parameters to use for formatting.
Returns:
update expression, dict of values.
"""
update_expression = ["set "]
update_values = dict()
for key, val in body.items():
update_expression.append(f" {key} = :{key},")
update_values[f":{key}"] = val
return "".join(update_expression)[:-1], update_values
Here is a quick example:
def update(body):
a, v = get_update_params(body)
response = table.update_item(
Key={'uuid':str(uuid)},
UpdateExpression=a,
ExpressionAttributeValues=dict(v)
)
return response
The original code example:
response = table.update_item(
Key={'ReleaseNumber': '1.0.179'},
UpdateExpression='SET',
ConditionExpression='Attr(\'ReleaseNumber\').eq(\'1.0.179\')',
ExpressionAttributeNames={'attr1': 'val1'},
ExpressionAttributeValues={'val1': 'false'}
)
Fixed:
response = table.update_item(
Key={'ReleaseNumber': '1.0.179'},
UpdateExpression='SET #attr1 = :val1',
ConditionExpression=Attr('ReleaseNumber').eq('1.0.179'),
ExpressionAttributeNames={'#attr1': 'val1'},
ExpressionAttributeValues={':val1': 'false'}
)
In the marked answer it was also revealed that there is a Range Key so that should also be included in the Key. The update_item method must seek to the exact record to be updated, there's no batch updates, and you can't update a range of values filtered to a condition to get to a single record. The ConditionExpression is there to be useful to make updates idempotent; i.e. don't update the value if it is already that value. It's not like a sql where clause.
Regarding the specific error seen.
ExpressionAttributeNames is a list of key placeholders for use in the UpdateExpression, useful if the key is a reserved word.
From the docs, "An expression attribute name must begin with a #, and be followed by one or more alphanumeric characters". The error is because the code hasn't used an ExpressionAttributeName that starts with a # and also not used it in the UpdateExpression.
ExpressionAttributeValues are placeholders for the values you want to update to, and they must start with :
Based on the official example, here's a simple and complete solution which could be used to manually update (not something I would recommend) a table used by a terraform S3 backend.
Let's say this is the table data as shown by the AWS CLI:
$ aws dynamodb scan --table-name terraform_lock --region us-east-1
{
"Items": [
{
"Digest": {
"S": "2f58b12ae16dfb5b037560a217ebd752"
},
"LockID": {
"S": "tf-aws.tfstate-md5"
}
}
],
"Count": 1,
"ScannedCount": 1,
"ConsumedCapacity": null
}
You could update it to a new digest (say you rolled back the state) as follows:
import boto3
dynamodb = boto3.resource('dynamodb', 'us-east-1')
try:
table = dynamodb.Table('terraform_lock')
response = table.update_item(
Key={
"LockID": "tf-aws.tfstate-md5"
},
UpdateExpression="set Digest=:newDigest",
ExpressionAttributeValues={
":newDigest": "50a488ee9bac09a50340c02b33beb24b"
},
ReturnValues="UPDATED_NEW"
)
except Exception as msg:
print(f"Oops, could not update: {msg}")
Note the : at the start of ":newDigest": "50a488ee9bac09a50340c02b33beb24b" they're easy to miss or forget.
Small update of Jam M. Hernandez Quiceno's answer, which includes ExpressionAttributeNames to prevent encoutering errors such as:
"errorMessage": "An error occurred (ValidationException) when calling the UpdateItem operation:
Invalid UpdateExpression: Attribute name is a reserved keyword; reserved keyword: timestamp",
def get_update_params(body):
"""
Given a dictionary of key-value pairs to update an item with in DynamoDB,
generate three objects to be passed to UpdateExpression, ExpressionAttributeValues,
and ExpressionAttributeNames respectively.
"""
update_expression = []
attribute_values = dict()
attribute_names = dict()
for key, val in body.items():
update_expression.append(f" #{key.lower()} = :{key.lower()}")
attribute_values[f":{key.lower()}"] = val
attribute_names[f"#{key.lower()}"] = key
return "set " + ", ".join(update_expression), attribute_values, attribute_names
Example use:
update_expression, attribute_values, attribute_names = get_update_params(
{"Status": "declined", "DeclinedBy": "username"}
)
response = table.update_item(
Key={"uuid": "12345"},
UpdateExpression=update_expression,
ExpressionAttributeValues=attribute_values,
ExpressionAttributeNames=attribute_names,
ReturnValues="UPDATED_NEW"
)
print(response)
An example to update any number of attributes given as a dict, and keep track of the number of updates. Works with reserved words (i.e name).
The following attribute names shouldn't be used as we will overwrite the value: _inc, _start.
from typing import Dict
from boto3 import Session
def getDynamoDBSession(region: str = "eu-west-1"):
"""Connect to DynamoDB resource from boto3."""
return Session().resource("dynamodb", region_name=region)
DYNAMODB = getDynamoDBSession()
def updateItemAndCounter(db_table: str, item_key: Dict, attributes: Dict) -> Dict:
"""
Update item or create new. If the item already exists, return the previous value and
increase the counter: update_counter.
"""
table = DYNAMODB.Table(db_table)
# Init update-expression
update_expression = "SET"
# Build expression-attribute-names, expression-attribute-values, and the update-expression
expression_attribute_names = {}
expression_attribute_values = {}
for key, value in attributes.items():
update_expression += f' #{key} = :{key},' # Notice the "#" to solve issue with reserved keywords
expression_attribute_names[f'#{key}'] = key
expression_attribute_values[f':{key}'] = value
# Add counter start and increment attributes
expression_attribute_values[':_start'] = 0
expression_attribute_values[':_inc'] = 1
# Finish update-expression with our counter
update_expression += " update_counter = if_not_exists(update_counter, :_start) + :_inc"
return table.update_item(
Key=item_key,
UpdateExpression=update_expression,
ExpressionAttributeNames=expression_attribute_names,
ExpressionAttributeValues=expression_attribute_values,
ReturnValues="ALL_OLD"
)
Hope it might be useful to someone!
In a simple way you can use below code to update item value with new one:
response = table.update_item(
Key={"my_id_name": "my_id_value"}, # to get record
UpdateExpression="set item_key_name=:item_key_value", # Operation action (set)
ExpressionAttributeValues={":value": "new_value"}, # item that you need to update
ReturnValues="UPDATED_NEW" # optional for declarative message
)
Simple example with multiple fields:
import boto3
dynamodb_client = boto3.client('dynamodb')
dynamodb_client.update_item(
TableName=table_name,
Key={
'PK1': {'S': 'PRIMARY_KEY_VALUE'},
'SK1': {'S': 'SECONDARY_KEY_VALUE'}
}
UpdateExpression='SET #field1 = :field1, #field2 = :field2',
ExpressionAttributeNames={
'#field1': 'FIELD_1_NAME',
'#field2': 'FIELD_2_NAME',
},
ExpressionAttributeValues={
':field1': {'S': 'FIELD_1_VALUE'},
':field2': {'S': 'FIELD_2_VALUE'},
}
)
using previous answer from eltbus , it worked for me , except for minor bug,
You have to delete the extra comma using update_expression[:-1]
I am trying to run the following query:
data = {
'user_id':1,
'text':'Lorem ipsum',
'$inc':{'count':1},
'$set':{'updated':datetime.now()},
}
self.db.collection('collection').update({'user_id':1}, data, upsert=True)
but the two '$' queries cause it to fail. Is it possible to do this within one statement?
First of all, when you ask a question like this it's very helpful to add information on why it's failing (e.g. copy the error).
Your query fails because you're mixing $ operators with document overrides. You should use the $set operator for the user_id and text fields as well (although the user_id part in your update is irrelevant at this example).
So convert this to pymongo query:
db.test.update({user_id:1},
{$set:{text:"Lorem ipsum", updated:new Date()}, $inc:{count:1}},
true,
false)
I've removed the user_id in the update because that isn't necessary. If the document exists this value will already be 1. If it doesn't exist the upsert will copy the query part of your update into the new document.
If you're trying to do the following:
If the doc doesn't exist, insert a new doc.
If it exists, then only increment one field.
Then you can use a combo of $setOnInsert and $inc. If the song exists then $setOnInsert won't do anything and $inc will increase the value of "listened". If the song doesn't exist, then it will create a new doc with the fields "songId" and "songName". Then $inc will create the field and set the value to be 1.
let songsSchema = new mongoose.Schema({
songId: String,
songName: String,
listened: Number
})
let Song = mongoose.model('Song', songsSchema);
let saveSong = (song) => {
return Song.updateOne(
{songId: song.songId},
{
$inc: {listened: 1},
$setOnInsert: {
songId: song.songId,
songName: song.songName,
}
},
{upsert: true}
)
.then((savedSong) => {
return savedSong;
})
.catch((err) => {
console.log('ERROR SAVING SONG IN DB', err);
})