I am little confused about retrieving data from dynamodb ... connecting is not an issue cause I am getting The provided key element does not match the schema
:the example provided from AWS
var table = new AWS.DynamoDB({params: {TableName: 'MY_TABLE'}});
var key = 'UNIQUE_KEY_ID';
var itemParams = {Item: {id: {S: key}, data: {S: 'data'}}};
table.getItem({Key: {id: {S: key}}}, function(err, data) {
console.log(data.Item); // print the item data
});
in my case the unique key is "time" and what I want to do is retrieve by key (not unique)
getItem only works on the primary key. From the docs: The GetItem operation returns a set of attributes for the item with the given primary key. See docs.
To solve this, create a Global Secondary Index that has "key" as HASH and "time" as RANGE. Then do a query operation using that index as IndexName:
var params = {
IndexName: 'your-new-GSI-index',
KeyConditionExpression: '#key = :key',
ExpressionAttributeNames: { '#key': 'key },
ExpressionAttributeValues: { ':key': { S: yourKeyVar } }
}
table.query(params, callback);
(did not test this code, but should work)
Related
I am using JS SDK with DynamoDB to fetch data.
I am able to fetch data from my table using simple query with partition key and sort key.
My sort key sk has records -
Year#Batch#Rate
If I pass var sk = "2006#CSE#90"; it returns all of records matching this,
Requirement - How can I get all products with year 2006 , Batch CSE AND Rate =>90
readItem_pbro(){
console.log("inside pbro");
var table2 = "pbro";
var pk = "1";
var sk = "2006#CSE#90";
var params2 = {
TableName: table2,
Key:{
"pk": pk,
"sk": sk
}
};
Edit 1 :: Created a different column for score/rate as score. It is numeric.
Now my query in JS is -
but I am getting error - ValidationException: The provided key element does not match the schema
readItem_score_filter(){
console.log("inside pbro");
var table2 = "pbro";
var pk = "1"; // string
var sk = "2006#CSE"; // string
var score = 90; //number
var params2 = {
TableName: table2,
Key:{
"pk": pk,
"sk": sk,
FilterExpression:'score >=:score',
}
};
what is wrong in my FilterExpression.
Edit 2 :: Added Key condition Expression but issue still remains the same
Error: ValidationException: The provided key element does not match the schema
Here is my complete function now:
readItem_score_filter(){
console.log("inside pbro");
var table2 = "pbro";
var pk = "1"; //string
var sk = "2006#CSE"; // string
var score = 90; //number
var params2 = {
TableName: table2,
Key:{
"pk": pk,
"sk": sk,
"score": score,
KeyConditionExpression: 'pk = :pk AND sk=:sk',
FilterExpression: "score >=:score",
}
};
this.user.docClient.get(params2, function(err, data) {
if (err) {
console.log(err);
} else {
console.log(data);
}
});
}
Screenshot of table attached incase you need to see::
If "2006#CSE#90" this is the value of sort key column then you cant do anything at Dynamodb level..
comparings like this can be done through regular expressions but DynamoDB doesn't support Regular Expressions.
you simply need to get results and then seperate these values and compare ..
Updated :- use different column for score.
And use Filter Expression to get records having rate more than 90.
I dont know python , but still am trying here
var params2 = {
TableName: "pbro",
KeyConditionExpression: "pk = :pk AND sk =:sk",
FilterExpression: "score >= :score"
};
I'm trying to get a specific item from a table.
My DynamoDB table name is table and I have:
Name PK | Number<br/>
S: Juan | S: #####
When I try to run in Lambda I don't get any Item when it really exist one with that name... any idea why it's like that?
AWS = require("aws-sdk"),
DDB = new AWS.DynamoDB({
region: "REGION",
}),
lookup_name_str = name //From Intent variable,
params = {
TableName: "table",
KeyConditionExpression: "name = :v1",
ExpressionAttributeValues: {
":v1":{
"S": lookup_name_str
}
},
FilterExpression: 'contains(nomColaborador,:v1)',
ProjectionExpression: "Number"
};
console.log(params);
var docClient = new AWS.DynamoDB.DocumentClient();
docClient.scan(params, function(err, data){
if(err){
throw err;
}
if(data.Items && data.Items[0] && data.Items[0].Number){
console.log("There is a Name with that number");
console.log(data.Items[0]);
my_response.statusCode = 200;
my_response.body = {
"sessionAttributes": {
"extension_str": data.Items[0].Number.S,
"nomColaborador": event.currentIntent.slots.Name
},
"dialogAction":{
"type": "Close",
"fulfillmentState": "Fulfilled",
"message": {
"contentType": "PlainText",
"content": data.Items[0].Number.S
}
}
};
The main problem here is that you are doing a scan. KeyConditionExpression isn't a parameter of a scan request. If you are requesting a single item by key you want to use getItem. If you need to query data by partition key and an optional sort key you should use query.
With that all said, when you do a scan, or put a filter on a query, you really need to be sure to page through the data. You will often find that you'll get a response with no data, but a paging key to make another call.
Say I want to add a record like below:
{
id:876876,
username:example,
email:xxxxxx#xxx.com,
phone:xxxxxxx,
created_at:current_date,
updated_at:current_date
}
What I want is to check with the id if record exist created_date should not be modified only updated_date should have current_date.
Can we do this with put method without having to be making a get item call?
To create a new item or update an existing item with conditional expression. Prefer to use updateItem rather than putItem.
If the Hash key (Primary key) doesn't exist both putItem and updateItem create a new record. If the record already exist, putItem will completely override the existing row but updateItem only updates the attributes passed in UpdateExpression not a whole record.
In your case, use if_not_exists() function to check whether the created_at field already exists or not. If exists created_at will not be overridden.
Update expression: "SET #email = :email, #created_at = if_not_exists(#created_at, :created_at), #updated_at = :updated_at"
Sample snippet
var params = {
ExpressionAttributeNames: {
"#email": "email",
"#created_at": "created_at",
"#updated_at": "updated_at"
},
ExpressionAttributeValues: {
":email": {
S: "test2#grr.la"
},
":created_at": {
S: date.toISOString()
},
":updated_at": {
S: date.toISOString()
}
},
Key: {
"id": {
S: "T1"
}
},
ReturnValues: "ALL_NEW",
TableName: "stack",
UpdateExpression: "SET #email = :email, #created_at = if_not_exists(#created_at, :created_at), #updated_at = :updated_at"
};
ddb.updateItem(params, function(err, data) {
if (err) console.log(err, err.stack); // an error occurred
else console.log(data);
})
I need another set of eyes on this. For the life of me I see no issues with this parameter set, used for Dynamo DocumentClient, update method - (here: https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#update-property ).
{
TableName: "mygame-dev",
Key: { pk: "09d017aa-cbf7-42ce-be6a-a94ecb58f9a7", sk: "GAME" },
ExpressionAttributeNames: { "#GAMELASTUPDATED": "gameLastUpdated", "#GAMETITLE": "gameTitle" },
ExpressionAttributeValues: { ":gamelastupdated": 1556376010704, ":gametitle": "test title 1" },
UpdateExpression: "SET #GAMELASTUPDATED = :gamelastupdated, #GAMETITLE = :gametitle",
ReturnValues: "ALL_NEW"
};
Error:
ValidationException: ExpressionAttributeNames can only be specified
when using expressions
Any thoughts?
Disregard, this was a copy and paste issue... I was using "query" not "update"
Was:
const updateGameResult = await ddbCall("query", params);
Should have been:
const updateGameResult = await ddbCall("update", params);
I have a scenario where I want to create an item if it doesn't exist, or update an item - incrementing a total, if it already exists.
I was running into problems splitting the two operations, so I am now trying to do both using UpdateItem in a single command.
I've tried 3 different approaches none work, and they have different errors listed below, the problem it seems is creating the map and trying to update it in a single command - what should my update params look like?
Attempt one:
{
TableName: TableName,
Key: {
'key': key
},
UpdateExpression: `
ADD #total :change
, mapname.#type.#total :one
`,
ExpressionAttributeValues: {
':change': change,
':one': 1
},
ExpressionAttributeNames: {
'#type': 'dynamicstring',
'#total': 'total'
}
};
With an error of: ValidationException: The document path provided in the update expression is invalid for update
Attempt two:
{
TableName: TableName,
Key: {
"key": key
},
UpdateExpression: `
SET custommap = if_not_exists(custommap, :emptyMap)
SET #total = #total + :change,
custommap.#type.#total = custommap.#type.#total + :one
`,
ExpressionAttributeValues: {
':change': change,
':one': 1,
':emptyMap': {
'M': {
'dynamicstring': {
'M': {
'total': {
'N': 0
}
}
}
}
}
},
ExpressionAttributeNames: {
'#type': 'dynamicstring',
'#total': 'total'
}
}
With an error of: ValidationException: Invalid UpdateExpression: The "SET" section can only be used once in an update expression;
So when I use UpdateItem to create or update (increment) a map within an Item, what syntax is correct?
Thanks
SET will only stop you overwriting an attribute, not an item.
They way to achieve this is:
Use GetItem with your key to see if the item already exists
If the item exists, then do an UpdateItem and increment the counter
If the item does not exist, then use PutItem