dynamodb add item to the array list - amazon-dynamodb

Using serverless-stack.
I have a table company with multiple branches:
new sst.Table(this, 'Company', {
fields: {
userId: sst.TableFieldType.STRING,
companyId: sst.TableFieldType.STRING,
companyName: sst.TableFieldType.STRING,
branches: [
{
branchId: sst.TableFieldType.STRING,
branchName: sst.TableFieldType.STRING
}
]
},
primaryIndex: {partitionKey: "userId", sortKey: "companyId"}
})
I am trying to add branch to the branches:
const branch = {
branchId: uuid.v1(),
branchName: data.branchName
}
const params = {
TableName: process.env.COMPANY_TABLE_NAME,
Key: {userId: "1", companyId: data.companyId},
UpdateExpression: "ADD #branches :branch",
ExpressionAttributeNames: { "#branches" : "branches" },
ExpressionAttributeValues: { ":branch": [branch] }
}
But I get this error:
ERROR ValidationException: Invalid UpdateExpression: Incorrect operand type for operator or function; operator: ADD, operand type: LIST, typeSet: ALLOWED_FOR_ADD_OPERAND
ValidationException: Invalid UpdateExpression: Incorrect operand type for operator or function; operator: ADD, operand type: LIST, typeSet: ALLOWED_FOR_ADD_OPERAND

ADD is only for numbers and sets. Your branches attribute is a list. So you can use SET with list_append.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html#Expressions.UpdateExpressions.SET.UpdatingListElements

SET #branches = list_append(#branches, :branch) is correct. But ExpressionAttributeValues should be ExpressionAttributeValues: { ":branch": {"L":[branch]}}
You can refer to https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/dynamodb.html#DynamoDB.Client.update_item

Related

DynamoDB update map value only if versions match

I have the following schema:
{
balance: {
customData: string,
version: number
}
}
I need to update balance.customData only if version == 2. Once update operation succeeds, I need to increment version by 1.
I tried the following update transaction
Update: {
Key: {
'pk': pk,
'sk': sk
},
TableName: this.config.getTable(),
UpdateExpression: 'SET #balance.#customData = :customData, #balance.#version = #balance.#version + :incr',
ConditionExpression: '#balance.#customData.#version = :version',
ExpressionAttributeNames: {
'#customData': 'customData',
'#balance': 'balance',
'#version': 'version'
},
ExpressionAttributeValues: {
':customData': balance.customData,
':version': balance.version,
':incr': {'N': 1},
}
}
But when I run this, I get ValidationException: Invalid UpdateExpression: Incorrect operand type for operator or function; operator or function: +, operand type: M
I assume I'm not providing correct syntax to increment map value.
Even if I remove increment part
Update: {
Key: {
'pk': pk,
'sk': sk
},
TableName: this.config.getTable(),
UpdateExpression: 'SET #balance.#customData = :customData,
ConditionExpression: '#balance.#customData.#version = :version',
ExpressionAttributeNames: {
'#customData': 'customData',
'#balance': 'balance',
'#version': 'version'
},
ExpressionAttributeValues: {
':customData': balance.customData,
':version': balance.version
}
}
I still get ValidationError with reason Other, which is not very helpful. Can you please help me understand what I'm doing wrong? Thanks

Dynamodb - Condition Expression with ExpressionAttributeNames not working

Am trying to do a conditional update and since the field name is a reserved keyword, am using ExpressionAttributeNames to pass in the column name for the condition. The update part isn't working if i use the ExpressionAttributeNames. Any thoughts?
Update: {
Key: {
"pk": "sb#prd#" + productId,
"sk": productId.toString()
},
TableName: 'test',
ConditionExpression: '#minQty >= :minQty',
UpdateExpression: "set sold_count = :sold_count",
ExpressionAttributeNames: {
"#minQty" : "variant[0].items[0].availableQty"
},
ExpressionAttributeValues: {
":sold_count" : 1,
":minQty" : 1
},
}
The aliases defined in ExpressionAttributeNames can only be a single attribute name - they cannot be full paths like variant[0].items[0].availableQty.
You can do something like:
ConditionExpression: '#v[0].#i[0].#a >= :minQty',
ExpressionAttributeNames: {
"#v" : "variant",
"#i" : "items",
"#a" : "availableQty"
},

ConditionalExpression DynamoDb Insert

I have the below data schema for my DynamoDb table. I am trying to append list subscribers on the condition if input = name (ex: input = my-topic2). There can be many maps in the “topics” list and I need to search for the map where the name = input and from there add the subscriber to that topic.
{
“server-id”: “123345678”,
“server-name”: “my-server”
“topics”: [
{
“name”: “my-topic”,
“subscribers”: []
},
{
“name”: “my-topic2”,
“subscribers”: [] //This is what I need to append on a condition that the input = “my-topic2”
}
]
}
I have the current following paeans I am using which appends “my-topic” subscribers.
params = {
ExpressionAttributeNames: {
"#T": "topics",
"#S": "subscribers"
},
ExpressionAttributeValues: {
":vals": [
message.author.id
]
},
Key: {
'server-id': serverID
},
ReturnValues: "ALL_NEW",
TableName: tableName,
UpdateExpression: "SET #T[0].#S = list_append(#T[0].#S, :vals)"
};

How to add items to a map in DynamoDB

I'm using the AWS.DynamoDB.DocumentClient with nodejs (lambda functions on AWS)
I've to a db called Translations, primary key Term, sort key Category.
Basically I'm trying to write data in like this:
{
Term: 'hello_there',
Category: 'common_phrases',
Translations: {
en-ca: 'Hello There!'
}
}
and I want to update Translations Map to perhaps add another language, or just modify the en-ca portion of the object.
I've tried the following:
let params = {
TableName: 'Translations',
Key: {
Term: 'hello_there',
Category: 'common_phrases',
},
UpdateExpression:
'SET Translations.#lang = list_append(Translations, :term)',
ExpressionAttributeValues: {
':term': 'french version',
},
ExpressionAttributeNames: {
'#lang': 'fr-ca',
},
}
But I get an error about the wrong operand type.
I've tried:
UpdateExpression:
'SET Translations.#lang = :term',
ExpressionAttributeValues: {
':term': 'french version',
},
ExpressionAttributeNames: {
'#lang': 'fr-ca',
},
But this overwrites the entire contents of the Translations field. Meaning that if I already had en-ca in there, now I would only have fr-ca.
I tried this as well, but also get an operand error:
{
UpdateExpression: 'ADD Translations :term',
ExpressionAttributeValues: {
':term': { 'fr-ff': 'frenchterm' },
},
Any suggestions on how to add/update items to the Translations Map?
Your SET expression was close, try something like this:
UpdateExpression:
'SET #trans.#lang = :term',
ExpressionAttributeValues: {
':term': 'french version',
},
ExpressionAttributeNames: {
'#trans': 'Translations`,
'#lang': 'fr-ca',
},

How to create and populate lists in DynamoDB

I wish to create an Item in DynamoDB that is a list. This is my code:
var list_update_params = {
TableName: "table01",
Key: {
"MachineID": {
"S": MachineID
},
"Hour": {
"S": Hour
}
},
UpdateExpression: "set var01_list = list_append(var01_list, :ot)",
ExpressionAttributeValues: {
":ot": {"L": [{"N": var01}]}
},
ReturnValues: "NONE"
};
dynamodb.updateItem(list_update_params, function(err, data) {
if (err) console.log(err, err.stack);
else console.log("Updated List to DynamoDB");
});
The problem is list_append expects the attribute var01_list to already be present, but I wouldn't know at the first insert. Is there a technique where it'll let me create an insert a List attribute if one doesn't exist and append to it in later calls?
Got the answer from a similar post here.
UpdateExpression: "set var01_list= list_append(if_not_exists(var01_list, :empty_list), :h)",
ExpressionAttributeValues: {
":h": {"L": [{"N":var01}]},
":empty_list": {"L": []}
},
The key was using if_not_exists with list_append. Didn't know that could be done in this matter

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