I have a dynamodb table with a partition key for client_id and no sort key. The json stored in the table just contains the client_id and compliance_level (which is a string title). I need to query the table for a list of client_id's because there is an application that displays client information in a tabular display. I am trying to use ExpressionFilter but get an "Error ValidationException: Either the KeyConditions or KeyConditionExpression parameter must be specified in the request." exception. I don't however have a keycondition to query on. Any assistance would be appreciated. I can't use batchgetitem as there will be more than 100 items to get the status for.
var AWS = require('aws-sdk');
AWS.config.update({region: 'ap-southeast-2'});
var ddb = new AWS.DynamoDB({apiVersion: '2012-08-10'});
var params = {
TableName : "Client-Compliance",
ProjectionExpression: "username, version",
FilterExpression : "client_id IN (:client1, :client2)",
ExpressionAttributeValues : {
":client1" : { "S": "c1234567" },
":client2" : { "S": "c88888888" }
}
};
ddb.query(params, function(err, data) {
if (err) {
console.log("Error", err);
} else {
console.log(data);
}
});
Many thanks
Related
I'm adding a sort field to one of my AppSync tables using GraphQL. The new schema looks like:
type MyTable
#model
#auth(rules: [{allow: owner}])
#key(name: "BySortOrder", fields: ["sortOrder"], queryField: "tableBySortOrder")
{
id: ID!
name: String!
sortOrder: Int
}
However, when retrieving a list using tableBySortOrder I get an empty list because the new field sortOrder is null.
My question is, how do I backfill this data in the DynamoDB table so that my existing users will not be disrupted by this new change? With a traditional database, I would run a SQL update: UPDATE MyTable SET sortOrder = #.
However, I'm new to NoSQL/AWS and couldn't find a way to do this except build a backfill script whenever a user logs into my app. That feels very hacky. What is the best practice for handling this type of scenario?
Have you already created the new field in DDB?
If yes, I think you should backfill it before making the client side change.
Write a script to iterate through and update the table. Options for this:
Java - Call updateItem to update the table if you have any integ tests running.
Bash - Use AWS CLI: aws dynamodb scan --table-name item_attributes --projection-expression "whatever" > /tmp/item_attributes_table.txt and then aws dynamodb update-item --table-name item_attributes --key. This is a dirty way.
Python - Same logic as above.
Ended up using something similar to what Sunny suggested with a nodejs script:
const AWS = require('aws-sdk')
AWS.config.update({
region: 'us-east-1'
})
// To confirm credentials are set
AWS.config.getCredentials(function (err) {
if (err) console.log(err.stack)
// credentials not loaded
else {
console.log('Access key:', AWS.config.credentials.accessKeyId)
console.log('Secret access key:', AWS.config.credentials.secretAccessKey)
}
})
const docClient = new AWS.DynamoDB.DocumentClient()
const table = 'your-table-dev'
const params = {
TableName: table
}
const itemMap = new Map()
// Using scan to retrieve all rows
docClient.scan(params, function (err, data) {
if (err) {
console.error('Unable to query. Error:', JSON.stringify(err, null, 2))
} else {
console.log('Query succeeded.')
data.Items.forEach(item => {
if (itemMap.has(item.owner)) {
itemMap.set(item.owner, [...itemMap.get(item.owner), item])
} else {
itemMap.set(item.owner, [item])
}
})
itemMap.forEach(ownerConnections => {
ownerConnections.forEach((connection, index) => {
connection.sortOrder = index
update(connection)
})
})
}
})
function update(connection) {
const params = {
TableName: table,
Key: {
'id': connection.id
},
UpdateExpression: 'set sortOrder = :s',
ExpressionAttributeValues: {
':s': connection.sortOrder,
},
ReturnValues: 'UPDATED_NEW'
};
console.log('Updating the item...');
docClient.update(params, function (err, data) {
if (err) {
console.error('Unable to update item. Error JSON:', JSON.stringify(err, null, 2));
} else {
console.log('UpdateItem succeeded:', JSON.stringify(data, null, 2));
}
});
}
My DynamoDB table alexas has this item with key "abc" as seen in the DynamoDB console below:
However, the following query returns no result:
const params = { TableName: "alexas",
KeyConditionExpression: "deviceId = :deviceId",
ExpressionAttributeValues: { ":deviceId": "abc"}
}
const docClient = new AWS.DynamoDB.DocumentClient();
docClient.query(params, (err, data) => {
if (err) {
console.error(err);
} else {
console.log(data);
}
});
The above code returns null for err and in data:
{ Items: [], Count: 0, ScannedCount: 0 }
I am new to the DynamoDB style of expressions. Is there anything wrong with my code which I took from here.
If instead of query, I used the scan method and just have TableName in params, I get the items in my table. This confirms that I am performing the operations on the correct table that has data.
The query returned no data because the key value does not match.
The item's deviceId is the string "abc" and not abc. Note the extra quotation marks.
The item was inserted using the DynamoDB console's Create editor and there is no need to include "" if the value is already expected to be of type string.
DynamoDB's Scan operation doesn't take a KeyConditionExpression - only the Query operation takes this parameter. Scan always scans the entire table, and has a FilterExpression to post-filter these results (however please note that you still pay for scanning the entire table).
For example, here is the official documentation of Scan: https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Scan.html
Check QueryAPI
const params = { TableName: "alexas",
KeyConditionExpression: "deviceId = :deviceId",
ExpressionAttributeValues: {
":devideId":{
S: "abc", // here
}
}
}
const docClient = new AWS.DynamoDB.DocumentClient();
docClient.query(params, (err, data) => {
if (err) {
console.error(err);
} else {
console.log(data);
}
});
ExpressionAttributeValues needs to be passed in a different manner.
Update:
Try using Exp attribute names, (I'm not sure if this will make a difference)
var params = {
TableName: "alexas",
KeyConditionExpression: "#d = :dId",
ExpressionAttributeNames:{
"#d": "email"
},
ExpressionAttributeValues: {
":dId": "abc"
}
};
I'm trying to execute the below SP
function createMyDocument() {
var collection = getContext().getCollection();
var doc = {
"someId": "123134444",
};
var options = {};
options['PartitionKey'] = ["someId"];
var isAccepted = collection.upsertDocument(collection.getSelfLink(), doc, options, function (error, resources, options) {
});
}
and cosmos keeps on complaining that there's something wrong with the partition key
{ code: 400,
body: '{"code":"BadRequest","message":"Message: {\\"Errors\\":
[\\"PartitionKey extracted from document doesn\'t match the one specified in the header\\"]}
}
Does anyone have any idea how to pass in the partion key in options so it gets pass this validation ?
Figured it out. The error was with how we call the stored proc.
How we were doing it
client.executeStoredProcedure('dbs/db1/colls/coll-1/sprocs/createMyDocument',
{},
{} //Here you have to pass in the partition key
);
How it has to be
client.executeStoredProcedure('dbs/db1/colls/coll-1/sprocs/createMyDocument',
{},
{"partitionKey": "43321"}
);
I think you misunderstand the meaning of partitionkey property in the options[].
For example , my container is created like this:
The partition key is "name" for my collection here. You could check your collection's partition key.
And my documents as below :
{
"id": "1",
"name": "jay"
}
{
"id": "2",
"name": "jay2"
}
My partitionkey is 'name', so here I have two paritions : 'jay' and 'jay1'.
So, here you should set the partitionkey property to '123134444' in your question, not 'someId'.
More details about cosmos db partition key.
Hope it helps you.
I've written a API gateway to scan a dynamodb table and get values based on the condition and my code is as below.
var params = {
TableName: 'CarsData',
FilterExpression: '#market_category = :market_category and #vehicle_size = :vehicle_size and #transmission_type = :transmission_type and #price_range = :price_range and #doors = :doors',
ExpressionAttributeNames: {
"#market_category": "market_category",
"#vehicle_size": "vehicle_size",
"#transmission_type": "transmission_type",
"#price_range": "price_range",
"#doors": "doors"
},
ExpressionAttributeValues: {
":market_category": body.market_category,
":vehicle_size": body.vehicle_size,
":transmission_type": body.transmission_type,
":price_range": body.price_range,
":doors": body.doors
}
}
dynamodb.scan(params).promise().then(function (data) {
var uw = data.Items;
console.log(data + "\n" + JSON.stringify(data) + "\n" + JSON.stringify(data.Items));
var res = {
"statusCode": 200,
"headers": {},
"body": JSON.stringify(uw)
};
ctx.succeed(res);
}).catch(function (err) {
console.log(err);
var res = {
"statusCode": 404,
"headers": {},
"body": JSON.stringify({ "status": "error" })
};
ctx.succeed(res);
});
when I run this code, I get the result as expected. But when I was going through some online forums, I came to know that scanning is expensive compared to querying. But I'm unable to know on how can I change my query from scan to query. Here my primary key is ID. please let me know on how can I do this.
Thanks
Scan operation is more expensive comparing to query operation, in terms of performance as well as costing. Dynamodb calculates cost based on the number of read capacity units consumed for processing not on number of records returned.
Query operation finds value based on primary key (Hash) or composite primary key (Hash key and Sort Key).
Your schema should be redesigned with composite primary key(Hash key and Sort Key).
Its not neccessary to have column Id as primary Key like old school RDBMS. If you are not using Id effectively remove that column from your schema and redefine it with some other attributes. For an example am using Market Category (market_category ) as Hash Key & Price Range (price_range) as Range Key.
var params = {
"TableName": 'CarsData',
"ConsistentRead": true,
//Composite Primary Key in Key Condition Expression
"KeyConditionExpression": "#market_category = :market_category AND #price_range = :price_range",
//Remaining column in filter expression
"FilterExpression": '#vehicle_size = :vehicle_size and #transmission_type = :transmission_type and #doors = :doors',
"ExpressionAttributeNames": {
"#market_category": "market_category",
"#vehicle_size": "vehicle_size",
"#transmission_type": "transmission_type",
"#price_range": "price_range",
"#doors": "doors"
},
"ExpressionAttributeValues": {
":market_category": body.market_category,
":vehicle_size": body.vehicle_size,
":transmission_type": body.transmission_type,
":price_range": body.price_range,
":doors": body.doors
}
}
dynamodb.query(params).promise()
.then(function (data) {
console.log(data);
}).catch(function (err) {
console.log(err);
});
Hope this example will give you insights about using composite primary key,
Based on your usage choose the widely used columns for Hash & Range key.
I have a table with 4 fields
id -> hash
uniid -> global secondary index
email
status -> global secondary index
Is it possible to get all emails where uniid is foo using LastEvaluatedKey for pagination.
I am trying something like
var params = {
TableName : 'users',
IndexName : 'gsiuniid',
KeyConditionExpression : '#uniid = :uniid',
ExpressionAttributeNames : {
'#uniid': 'uniid'
},
ExpressionAttributeValues : {
':uniid': 'valid-uniid'
},
ExclusiveStartKey: {
'id' : 'id-from-last-query'
}
};
dynamodb.query(params, function (err, data) {
console.log(data);
});
And i get the error, The provided starting key is invalid.
I checked the db, the starting key, which is the id of the above table, exists.
Any ideas on what i am doing wrong?
can you change ExclusiveStartKey key?
ExclusiveStartKey: {
'#uniid' : 'id-from-last-query'
}