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How to remove last element in set in dynamo?

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0

I have created a set using dynamoDB document client . I am able to remove items in this set however when i remove to the last element in the set nothing returns until i make a new post. Then all the other data is displayed.

 const params = 
 TableName: 'beta-user-' + process.env.NODE_ENV,
 Key: 
 username: request.username
 ,
 UpdateExpression: "DELETE #features :feature",
 ExpressionAttributeNames: "#features" : "features" ,
 ExpressionAttributeValues: ":feature": dynamodb.createSet([request.feature]) ,
 ReturnValues: "NONE"
 ;

and im calling it like

const dynamoPromise = dynamodb.update(params).promise();
return await dynamoPromise.then(result => // stuff )

The UpdateExpression i do not think is wrong
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.DELETE

I belive the problem is with ExpressionAttributeValues if i remove
dynamodb.createSet I get many validation errors.

When i make a get request to app i get

 "message": [
 
 "username": "x",
 "feature": [
 "blah",
 "test"
 ]
 ,
 
 "username": "z",
 "feature": [
 "blah"
 ]
 ,

I make a delete request and remove the feature test from username x. This works and returns the same response minus the test feature. I make another delete request to remove blah. Blah is removed however when I make a get request I recieve:

 "message": 

The other data is returned when i make a new post to that specific user.

EDIT:

I think the issue might be due to dynamo not liking an empty set

node.js amazon-dynamodb serverless-framework

share|improve this question

edited Mar 26 at 15:10

jermiah

asked Mar 26 at 2:30

jermiahjermiah

111 bronze badge

add a comment | 

0

I have created a set using dynamoDB document client . I am able to remove items in this set however when i remove to the last element in the set nothing returns until i make a new post. Then all the other data is displayed.

 const params = 
 TableName: 'beta-user-' + process.env.NODE_ENV,
 Key: 
 username: request.username
 ,
 UpdateExpression: "DELETE #features :feature",
 ExpressionAttributeNames: "#features" : "features" ,
 ExpressionAttributeValues: ":feature": dynamodb.createSet([request.feature]) ,
 ReturnValues: "NONE"
 ;

and im calling it like

const dynamoPromise = dynamodb.update(params).promise();
return await dynamoPromise.then(result => // stuff )

The UpdateExpression i do not think is wrong
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.DELETE

I belive the problem is with ExpressionAttributeValues if i remove
dynamodb.createSet I get many validation errors.

When i make a get request to app i get

 "message": [
 
 "username": "x",
 "feature": [
 "blah",
 "test"
 ]
 ,
 
 "username": "z",
 "feature": [
 "blah"
 ]
 ,

I make a delete request and remove the feature test from username x. This works and returns the same response minus the test feature. I make another delete request to remove blah. Blah is removed however when I make a get request I recieve:

 "message": 

The other data is returned when i make a new post to that specific user.

EDIT:

I think the issue might be due to dynamo not liking an empty set

node.js amazon-dynamodb serverless-framework

share|improve this question

edited Mar 26 at 15:10

jermiah

asked Mar 26 at 2:30

jermiahjermiah

111 bronze badge

add a comment | 

I have created a set using dynamoDB document client . I am able to remove items in this set however when i remove to the last element in the set nothing returns until i make a new post. Then all the other data is displayed.

 const params = 
 TableName: 'beta-user-' + process.env.NODE_ENV,
 Key: 
 username: request.username
 ,
 UpdateExpression: "DELETE #features :feature",
 ExpressionAttributeNames: "#features" : "features" ,
 ExpressionAttributeValues: ":feature": dynamodb.createSet([request.feature]) ,
 ReturnValues: "NONE"
 ;

and im calling it like

const dynamoPromise = dynamodb.update(params).promise();
return await dynamoPromise.then(result => // stuff )

The UpdateExpression i do not think is wrong
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.DELETE

I belive the problem is with ExpressionAttributeValues if i remove
dynamodb.createSet I get many validation errors.

When i make a get request to app i get

 "message": [
 
 "username": "x",
 "feature": [
 "blah",
 "test"
 ]
 ,
 
 "username": "z",
 "feature": [
 "blah"
 ]
 ,

I make a delete request and remove the feature test from username x. This works and returns the same response minus the test feature. I make another delete request to remove blah. Blah is removed however when I make a get request I recieve:

 "message": 

The other data is returned when i make a new post to that specific user.

EDIT:

I think the issue might be due to dynamo not liking an empty set

node.js amazon-dynamodb serverless-framework

share|improve this question

edited Mar 26 at 15:10

jermiah

asked Mar 26 at 2:30

jermiahjermiah

111 bronze badge

 const params = 
 TableName: 'beta-user-' + process.env.NODE_ENV,
 Key: 
 username: request.username
 ,
 UpdateExpression: "DELETE #features :feature",
 ExpressionAttributeNames: "#features" : "features" ,
 ExpressionAttributeValues: ":feature": dynamodb.createSet([request.feature]) ,
 ReturnValues: "NONE"
 ;

 "message": [
 
 "username": "x",
 "feature": [
 "blah",
 "test"
 ]
 ,
 
 "username": "z",
 "feature": [
 "blah"
 ]
 ,

 "message": 

share|improve this question

edited Mar 26 at 15:10

jermiah

asked Mar 26 at 2:30

jermiahjermiah

111 bronze badge

share|improve this question

edited Mar 26 at 15:10

jermiah

asked Mar 26 at 2:30

jermiahjermiah

111 bronze badge

asked Mar 26 at 2:30

jermiahjermiah

111 bronze badge

asked Mar 26 at 2:30

jermiahjermiah

111 bronze badge

1 Answer
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The issue was with my return statement in my get request. I assumed that once features were deleted the record would be deleted. I was trying to return features on an object that had no features, therefore, it was erroring out and not returning anything.

share|improve this answer

answered Mar 26 at 15:26

jermiahjermiah

111 bronze badge

add a comment | 

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0

The issue was with my return statement in my get request. I assumed that once features were deleted the record would be deleted. I was trying to return features on an object that had no features, therefore, it was erroring out and not returning anything.

share|improve this answer

answered Mar 26 at 15:26

jermiahjermiah

111 bronze badge

add a comment | 

0

The issue was with my return statement in my get request. I assumed that once features were deleted the record would be deleted. I was trying to return features on an object that had no features, therefore, it was erroring out and not returning anything.

share|improve this answer

answered Mar 26 at 15:26

jermiahjermiah

111 bronze badge

add a comment | 

The issue was with my return statement in my get request. I assumed that once features were deleted the record would be deleted. I was trying to return features on an object that had no features, therefore, it was erroring out and not returning anything.

share|improve this answer

answered Mar 26 at 15:26

jermiahjermiah

111 bronze badge

share|improve this answer

answered Mar 26 at 15:26

jermiahjermiah

111 bronze badge

answered Mar 26 at 15:26

jermiahjermiah

111 bronze badge

answered Mar 26 at 15:26

jermiahjermiah

111 bronze badge