DynamoDB, Updating Multiple Nested Map Attribute - amazon-dynamodb

I have a top level attribute and I want to simultaneously update multiple nested attributes. The params I am passing in are:
{
"TableName":"LOCAL-Table",
"Key":{
"id":"1"
},
"UpdateExpression":"SET #param.#eb321fb16aab1745c55a8659be811f2d = :valeb321fb16aab1745c55a8659be811f2d , #param.#6e3c283fb60480af627ede2758e8e983 = :val6e3c283fb60480af627ede2758e8e983",
"ExpressionAttributeValues":{
":valeb321fb16aab1745c55a8659be811f2d":{
...
},
":val6e3c283fb60480af627ede2758e8e983":{
...
}
},
"ExpressionAttributeNames":{
"#eb321fb16aab1745c55a8659be811f2d":"eb321fb16aab1745c55a8659be811f2d",
"#6e3c283fb60480af627ede2758e8e983":"6e3c283fb60480af627ede2758e8e983",
"#param":"param"
},
"ReturnValues":"UPDATED_NEW"
}
It works when updating a single attribute, but when I put 2 in I get an error stating:
The document path provided in the update expression is invalid for update
Any help greatly appreciated.
Thanks

Actually, this does work, the problem was related to poorly sequenced promises resulting in a race condition.

Related

How to query documents where contains an array and the value of the array is ["val1", "val2"] Firestore

How can I get a collection where the query should be applicable to an array inside the document.
Document example: I would like to know how to query the document where the brands are fiat and seat
{
"name":"test 1",
"brands":[
{
"brand":{
"id":1,
"name":"Fiat",
"slug":"fiat",
"image":null,
"year_end":null,
"year_start":null
},
"released_at":"2018-10-26"
},
{
"brand":{
"id":2,
"name":"Seat",
"slug":"seat",
"image":null,
"year_end":null,
"year_start":null
},
"released_at":"2018-10-26"
},
{
"brand":{
"id":3,
"name":"Mercedes",
"slug":"mercedes",
"image":null,
"year_end":null,
"year_start":null
},
"released_at":"2018-10-26"
},
{
"brand":{
"id":4,
"name":"Yamaha",
"slug":"yamaha",
"image":null,
"year_end":null,
"year_start":null
},
"released_at":"2018-10-26"
}
]
}
I have tried something like:
.collection("motors")
.where("brands.slug", "array-contains-any", ["fiat", "seat"])
but this is not working I cannot figure out by the documentation how to get this.
When using the array-contains-any operator, you can check the values of your array against the value of a property of type String and not an array. There is currently no way you can use array-contains-any operator on an array. There are two options, one would be to create two separate fields and create two separate queries or, been only a document, you can get the entire document and filter the data on the client.
Edit:
What #FrankvanPuffelen has commented is correct, I made some research and I found that we can check against any type and even complex types, not just against strings, as mentioned before. The key to solving this issue is to match the entire object, meaning all properties of that object and not just a partial match, for example, one of three properties.
What you are trying to achieve is not working with your current database structure because your slug property exists in an object that is nested within the actual object that exists in your array. A possible solution might also be to duplicate some data and add only the desired values into an array and use the array-contains-any operator on this new creatded array.

Association cause foreing key mismatch error

I am currently experimenting on sequelize.js and more specifically in associations. What i am trying to achieve is the following. I have to models:
user
position
My logic is the following:
A user can or cannot have a position assigned to it
If a user has a position, the id of the position is stored in field "assignedPositionId" of users table.
If a user does not have a position, then "assignedPositionId" value is set to null.
A position can be assigned to more than one users
The issue i am facing is, that i can successfully create a user, but i am unable to create a position! I always keep getting the error message:
SQLITE_ERROR: foreign key mismatch - "positions" referencing "users"
User.hasOne(Position, {
sourceKey: "assignedPositionId",
foreignKey: "id",
as: "position"
});
Position.hasMany(User, {
sourceKey: "id",
foreignKey: "assignedPositionId",
as: "users",
});
I know it's something more than easy - maybe it's late but i really can't figure out what goes wrong! Your help is highly appreciated!
I've had problems using hasOne in these cases, tend to use belongsTo instead, e.g.
User.belongsTo(Position, {
foreignKey: "assignedPositionId",
as: "position"
});
That said, what does the SQL generated look like when you create a Position? Can you execute this directly in the Sqlite shell? That type of error message sometimes suggests a problem with your table PKs.
#KenOn10, thank you for your providing a suggestion. After carefully reading documentation and performing several tests, i ended up with the following approach, which works perfectly:
User.hasMany(Position, {
as: "position",
sourceKey: "assignedPositionId",
foreignKey: "id",
constraints: false
});
Position.belongsTo(User, {
as: "users",
foreignKey: "assignedPositionId",
constraints: false
});
Thank you again for your time.

How can I update deeply nested object inside array?

Hello good people of the stack!
I am working on a react-redux application and I am trying to update a property on a deeply nested structure in my reducer. The data structure is as follows and I want to update the text property:
state = {
assessment: {
requirements: [
questions: [
{
text
}
]
]
}
}
so I have tried the following:
// reducer code...
return {
...state,
[assessmentId]: {
...state[assessmentId],
requirements: [
...state[assessmentId].requirements,
[requirementId]: [
...state[assessmentId].requirements[requirementsId],
questions: [
...state[assessmentId].requirements[requirementsId].questions,
[questionId]: {
text: action.payload.response.text
},
],
] ,
],
},
};
This is more pseudo code than actual code to remove complexity.
I do not see any change in redux dev tools so I am wondering if I have made a mistake the way I get the nested objects and array elements.
I was also curious about using combine reducers here. I asked a colleague and they suggested to use that but I am unsure how you would take that approach here. As always, any help is appreciated.
I recommend immer for deep state changes in your reducers.
It adds a little weight to your bundle, and you'll get better performance from using the spread operator, but if you can live with that it'll make your code easier to read and write.
import produce from "immer";
// reducer code...
return produce(state, draft => {
draft[assessmentId].requirements[requirementsId].questions[questionsIndex].text = action.payload.response.text;
});
I'd say your issue stems from questions being an array which will take a little more work to keep straight than object based state.
As it is you appear to be trying to set the question value as if questions was an object. Maybe you just need to drop the [questionId] syntax, eg
questions: [
...state[assessmentId].requirements[requirementsId].questions,
{ text: action.payload.response.text },
],
This will set the text object as a new item on the end of the array though.
Depending on what you need to do (ie what already exists in the array and whether you are trying to add or update) you'll want to have a read of:
https://redux.js.org/recipes/structuring-reducers/immutable-update-patterns#inserting-and-removing-items-in-arrays
https://redux.js.org/recipes/structuring-reducers/immutable-update-patterns#updating-an-item-in-an-array

inserting a nested attributes array element in dynamodb table without retrieving the entire item

looking for an answer to this question if possible, not looking for a refactoring advice or redesign, i just need to understand what else I am missing here :
I have an existing item in dynamodb:
{
"CartId": 321,
"UserId": usr555,
"CartItems": [
{
"ProductId":59999,
"Quantity": 1
},
{
"ProductId": 58888,
"Quantity": 2
}
]
}
in my code I want to insert another nested attribute into the array CartItems in the item above. i can't find a way of doing this without retrieving the entire item and then inserting, which could amount to KBs in size.
all I want to do is insert a single array element in an existing nested attribute without having to retrieve the item.
the language I am using is nodejs and the function is DynamoDB.put.
UpdateExpression attribute supports SET action and SET action supports list_append function. Since list_append function operands must be list, enclose the new value within a list as below.
response = dynamodb_client.update_item(TableName='your_table',
Key={'CartId':'321'},
UpdateExpression='SET CartItems = list_append(CartItems, :val1)',
ExpressionAttributeValues = {':val1':[{'ProductId':12345, 'Quantity': 100}]})
Hope this helps

Firebase .indexOn with complex DB structure

The current query you see below is not efficient because I have not setup the proper indexing. I get the suggestion Consider adding ".indexOn": "users/kxSWLGDxpYgNQNFd3Q5WdoC9XFk2" at /conversations in the console in Xcode. I have tried it an it works.
However, I need the user id after users/ to be dynamic. I've added a link to another post below that has tried a similar thing, but I just can't seem to get it. All help would be much appreciated!
Note: The console output user id above does not match the screenshot below, but does not matter to solve the problem I believe. Correct me if I'm wrong. Thanks!
Here is the structure of my DB in Firebase:
{
"conversationsMessagesID" : "-KS3Y9dMLXfs3FE4nlm7",
"date" : "2016-10-19 15:45:32 PDT",
"dateAsDouble" : 4.6601793282986E8,
"displayNames" : [ “Tester 1”, “Tester 2” ],
"hideForUsers" : [ "SjZLsTGckoc7ZsyGV3mmwc022J93" ],
"readByUsers" : [ "mcOK5wVZoZYlFZZICXWYr3H81az2", "SjZLsTGckoc7ZsyGV3mmwc022J93" ],
"users" : {
"SjZLsTGckoc7ZsyGV3mmwc022J93" : true,
"mcOK5wVZoZYlFZZICXWYr3H81az2" : true
}
}
and the Swift query:
FIRDatabase.database().reference().child("conversations")
.queryOrderedByChild("users/\(AppState.sharedInstance.uid!)").queryEqualToValue(true)
Links to other post:
How to write .indexOn for dynamic keys in firebase?
It seems fairly simple to add the requested index:
{
"rules": {
"users": {
".indexOn": ["kxSWLGDxpYgNQNFd3Q5WdoC9XFk2", "SjZLsTGckoc7ZsyGV3mmwc022J93", "mcOK5wVZoZYlFZZICXWYr3H81az2"]
}
}
}
More likely your concern is that it's not feasible to add these indexes manually, since you're generating the user IDs in your code.
Unfortunately there is no API to generate indexes.
Instead you'll need to model your data differently to allow the query that you want to do. In this case, you want to retrieve the conversations for a specific user. So you'll need to store the conversations for each specific user:
conversationsByUser {
"SjZLsTGckoc7ZsyGV3mmwc022J93": {
"-KS3Y9dMLXfs3FE4nlm7": true
},
"mcOK5wVZoZYlFZZICXWYr3H81az2": {
"-KS3Y9dMLXfs3FE4nlm7": true
}
}
It may at first seem inefficient to store this data multiple times, but it is very common when using NoSQL databases. And is really no different than if the database would auto-generate the indexes for you, except that you have to write the code to update the indexes yourself.

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