21 DynamoDB Query Code Examples .NET/C# (2023)

DynamoDB is a NoSQL database hosted in the Amazon cloud. It offers reliable performance, a well-managed environment, and easy API access to interact with it.

This article will help you perform various queries against DynamoDB using C#.

If you are looking for a similar guide but for Node.js,you can find it here, forrosa, and toPython/boto3 here.

DynamoDB C# Query Sample List

  • Setting
  • create table
  • Consultation
  • delete table
  • delete element
  • Scan
  • Item Retrieval Using the Query Filter
  • set item
  • get all items
  • Get all articles (with pagination)
  • received a single item
  • update article
  • Retrieve items in batches
  • Get items from multiple tables
  • Batch write items
  • execute transactions
  • Run DynamoDB Local


To set up DynamoDB in the .NET environment, you need the AWSSDK.DynamoDBv2 package. Provides a .NET API that makes it easy to interact with DynamoDB to perform various query operations.

For the examples in this article, I use thelocal stackFrame. And the syntax remains the same for the actual DynamoDB instance by removing the service url parameter.

Let's see how to insert a new record and retrieve it by scanning the table or using a hash key.

Configuring the DynamoDB client

public Class Dynamo Client Configuration { Private read only AmazonDynamoDB client_amazonDynamoDBClient; Private read only DynamoDBContext_Context; public DynamoClient() { //localstack ignores secrets_amazonDynamoDBClient= nuevo AmazonDynamoDB client("Access ID", "awsSecretAccessKey", nuevo AmazonDynamoDBConfig {service url= "http://localhost:4569", //Standard-Localstack-URLUse HTTP= TRUE, });_Context= nuevo DynamoDBContext(_amazonDynamoDBClient, nuevo DynamoDBContextConfig {table name prefix= "proof_" }); }}

You must pass the accessId and accessKey to the AmazonDynamoDBClient constructor.

Create table and model class

To create the table, we are going to create the table creation request. To do this, we must specify all the declared keys of the table. If you have a lot of tables, this might be a bit formal; However, I will show several alternatives to make this process easier and faster in the future.

[DynamoDBTable("Employees")]public Class Look for: IEcuable<Employees> { [DynamoDBHashKey] public And tempId{ receive; Prayer; } public lineFirst name{ receive; Prayer; } public linelast name, last name{ receive; Prayer; } public bool Same(EmployeesOthers) { And (reference match(Null,Others)) go back INCORRECT; And (reference match(He,Others)) go back TRUE; go backID==Others.ID&& line.Same(First name,Others.First name) && line.Same(last name, last name,Others.last name, last name); } public overwrite bool Same(Objectobject) { And (reference match(Null,object)) go back INCORRECT; And (reference match(He,object)) go back TRUE; And (object.getType() != He.getType()) go back INCORRECT; go back Same((Student)object); } public overwrite And t get hash code() { rampant { GuerraHash code=empId;Hash code= (Hash code* 397) ^ (First name!= Null ?First name.get hash code() : 0);Hash code= (Hash code* 397) ^ (last name, last name!= Null ?last name, last name.get hash code() : 0); go backHash code; } }}

There are two unique attributes that we can use.

  • DynamoDBTable--- Allocate the equivalent DynamoDB table.
  • DynamoDBHashKey--- Assign the hash key of the table.
public asynchronous Task<CreateTableResponseCreateTableResponse> ConfigurationAsync() { GuerracreateTableRequest= nuevo CreateTableRequest {table name= "employee_test",attribute definitions= nuevo List<attribute definition> (),key scheme= nuevo List<KeySchemaElement> (),GlobalSecondaryIndexesGlobalSecondaryIndexes= nuevo List<Global Secondary Index> (),local secondary indexes= nuevo List<LocalSecondaryIndex> (),provisioned throughput= nuevo provisioned throughput {read capacity units= 1,Write Capacity Units= 1 } };createTableRequest.key scheme= nuevo [] { nuevo KeySchemaElement {attribute name= "same",key type=key type.HASHISH, }, }.List();createTableRequest.attribute definitions= nuevo [] { nuevo attribute definition {attribute name= "same",attribute type=ScalarAttributeType.norte, } }.List();}
(Video) Getting started with AWS DynamoDB in .NET


DynamoDB allows queries not only against the index of the main table, but also againstLSI (local secondary indexes)YGSI (Global Secondary Indexes).

public asynchronous Task SaveOderUpdateStudent(EmployeesEmployees) { wait_Context.GuardarAsync(Employees);}public asynchronous Task<Employees> GetEmployeeUsingHashKey(And tID) { go back wait_Context.LoadAsync <Employees> (empId);}public asynchronous Task<Employees> ScanForEmployeeUsingFirstName(lineFirst name) { Guerralook for=_Context.ScanAsync <Employees> ( nuevo [] { nuevo scan condition ( name of(Employees.First name),scan operator.Same,First name) } ); GuerraResult= waitlook for.GetRemainingAsync(); go backResult.ErsteOderStandard();}
  • SaveOrUpdateEmployee – To save a new entity, run SaveAsync. Remember that SaveAsync creates or updates the record; If the form already exists, the execution of the method overwrites the data in the matching record.
  • GetEmployeeUsingHashKey – This method retrieves the records using the hash key.
  • ScanForEmployeeUsingFirstName scans the entire table for the first name.

delete table

[Http Delete]public asynchronous Task extinguish(lineFirst name) { wait_dynamoDbContexto.EliminarAsync <Employees> (empId,First name,last name, last name);}

The DeleteAsync method deletes an element by specifying the partition and range key or by using the element itself.

delete element

low level model

public asynchronous Task delete element(linetable name) { GuerraConsultation= nuevo DeleteItemRequest {table name=table name,Gusto= nuevo dictionary< line,Attribute> { { "same", nuevo Attribute {norte= "999" } } }, }; wait_dynamoDbClient.DeleteItemAsync(Consultation);}

object persistence model

You can map your client-side classes to Amazon DynamoDB tables using the AWS SDK for .Net object persistence mechanism. The element is assigned to each object instance in the corresponding tables. The object persistence model provides the DynamoDBContext class, an entry point to DynamoDB, for storing client-side objects in tables. This class connects to DynamoDB so that it can view tables, perform CRUD actions, and run queries.

public asynchronous Task delete element(Article requestarticle request) { wait_Context.EliminarAsync(article request);}

We can do the above using the same model, including the table name and partition key.

Avoid overwriting existing records

public asynchronous Task SaveOnlyEmployee(EmployeesEmployees) { Guerraidentity event table=Tisch.loadtable(_amazonDynamoDBClient, "employee_test"); GuerraExpression= nuevo Expression {ExpressionAttributeNamesExpressionAttributeNames= nuevo dictionary< line, line > { { "#Gusto", name of(Employees.empId) }, },ExpressionAttributeValuesExpressionAttributeValuesExpressionAttributeValues= { { ":Gusto",Employees.empId}, },Expression Statement= "attribute_doesn't_exist(#key) ODER #key <> :key", }; Guerradocument=_Context.Document(Employees); waitidentity event table.PutItemAsync(document, nuevo PutItemOperationConfig {conditional expression=Expression,return values=return values.none});}
(Video) Using Amazon DynamoDb for ASP.NET Framework Session State

We need to use conditional expressions in DynamoDB to avoid overrides. If we try to insert a record that already has a hash key into the table, aConditionalCheckFailedExceptionit's charged.


You can filter the scan results by specifying scan criteria. Each attribute in the table is used to evaluate the condition. Suppose you have a client-side class called EmployeeCategory that maps to the DynamoDB employee table. The following C# example searches the table and returns only employee IDs greater than 10.

IEnumerable<Employees>elements with wrong ID=context.Scan <Employees> ( nuevo scan condition("same",scan operator.Less than,empId), nuevo scan condition("Employee Category",scan operator.Same, "Internal"));

The Scan method returns an IEnumerable collection that has been "lazy loaded". Initially it just returns a page of results and then makes a service request for the next page if needed. You just need to iterate through the IEnumerable to get all the matching entries.

Get articles with query filter

object persistence model

public asynchronous Task<IEnumerable<Article request>> GetUsersItemsByName(And tempId, lineempname) { GuerraSetting= nuevo DynamoDBOperationConfig {query filter= nuevo List<scan condition> { nuevo scan condition("name of the job",scan operator.Starts with,empname) } }; go back wait_Context.QueryAsync <Article request> (empId,Setting).GetRemainingAsync();}

low level model

public asynchronous Task<consultanswer> Get items by name(And tempId, lineempname) { GuerraConsultation= nuevo consultaSolicitud {table name=table name,key condition expression= "id = :empId and starts_with (name,:empname)",ExpressionAttributeValuesExpressionAttributeValuesExpressionAttributeValues= nuevo dictionary< line,Attribute> { { ":ID", nuevo Attribute {norte=ID.Chain() } }, { ":Name", nuevo Attribute {S=empname} } } }; go back wait_dynamoDbClient.QueryAsync(Consultation);}

set item

Replace an old article with a new article or create a new article. If an item with the same primary key already exists in the mounted database, it will be completely replaced with the new item. You can insert a new element if the supplied primary key does not exist, or return an existing element if it contains specific attribute values.

You can use the returnValues ​​option to return the values ​​of the element's attributes in the same action as inserting the element.

Primary key attributes are the only attributes required when adding an item. Null values ​​are not allowed for attribute values. String length and binary properties must be greater than zero. There must be no empty record type attributes. ValidationException is thrown for requests with open values.

PutItem can return a copy of the old item (before the update) or a copy of the new item (after the update).

public virtual Empty CreateAccountItem(AmazonDynamoDB clientddb client, linetable name, AccountAccount) { // Create sales request GuerraputItemRequest= nuevo PutItemRequest {table name=table name,Article= nuevo dictionary< line,Attribute> { { "Company", nuevo Attribute {S=Account.Look for} }, { "Email", nuevo Attribute {S=Account.Email} } } }; // Only add attributes if the corresponding property on the Account object is not empty. And (!line.is null or empty(Account.First)) {putItemRequest.Article.add("First", nuevo Attribute {S=Account.First}); } And (!line.is null or empty(Account.Last)) {putItemRequest.Article.add("Last", nuevo Attribute {S=Account.Last}); } And (!line.is null or empty(Account.To alter)) {putItemRequest.Article.add("To alter", nuevo Attribute {norte=Account.To alter}); } // Send the requestddb client.also put(putItemRequest);}
(Video) AWS DynamoDB PAGINATION | .NET ON AWS | AWS Serverless | Amazon

get all items

Let's find all the items on the table.

GuerraEmployees= wait GetAllEmployees();console.Write line(Employees.paging token);console.Write line(Employees.result type);for each(GuerraempInEmployees.Employees) {console.Write line(ps{emp.Email address}-{emp.empId}-{emp.To alter}-{emp.united the}- ADDRESS:{emp.ADDRESS.Calle},{emp.ADDRESS.Ciudad}");}

Get all articles (with pagination)

The following code shows the functionality of the GetAllEmployees method. First you need to get the model table reference and look for a paging token. You can use paginationToken with the scan option to get the following result set.

public static asynchronous Task<Employee View Model> GetAllEmployees(linepaging token= "") { GuerraTisch=context.GetDestinationTable <Employees> (); //Get PaginationToken to use for scanning GuerrascanOps= nuevo ScanOperationConfig(); And (!line.is null or empty(paging token)) {scanOps.paging token=paging token; } // returns the set of Document objects for the provided ScanOptions GuerraResults=Tisch.Scan(scanOps); List<Document>Data= waitResults.GetNextSetAsync(); IEnumerable<Employees>Employees=context.of documents <Employees> (Data); // Pass the PaginationToken, if available, from the results along with the result set go back nuevo Employee View Model {paging token=Results.paging token,Employees=Employees,result type=result type.List};}

received a single item

console.Write line("unique result");Guerraemployees found= wait Einzel("100e4548-1f68-4288-972d-81133b6dacb1",Convert.HastaFechaHora("2021-01-01T06:43:18.014Z"));And (employees found!= Null) {console.Write line(ps{employees found.Email address}-{employees found.ID}-{employees found.united the}");}public static asynchronous Task<Employees> Einzel(lineemployee ID, appointment timeunited the) { go back waitcontext.LoadAsync <Employees> (employee ID,united the);}

update article

public static asynchronous Task Update(lineemployee ID, EmployeeInputModellegal entity) { GuerraEmployees= wait Einzel(employee ID,legal entity.united the);Employees.Email address=legal entity.Email address;Employees.Username=legal entity.Username;Employees.Name=legal entity.Name; waitcontext.GuardarAsync <Employees> (Employees);}

Get items in batches

The following code retrieves three items from the EmployeeDetails table in C#. The result elements arenot necessarily in the same order as the primary keys you choose.

DynamoDBContextcontext= nuevo DynamoDBContext(Client);Guerraemployee batch=context.CreateBatchGet <details about employees> ();employee batch.add key(001);employee batch.add key(002);employee batch.add key(003);employee batch.Accomplish();// Get the result setconsole.Write line(employee batch.Results.To count);Employeesemp1=employee batch.Results[0];Employeesemp2=employee batch.Results[1];Employeesmp3=employee batch.Results[2];

When trying to retrieve multiple items from a database table with one query, you should consider the following:

  • You must create an instance of the CreateBatchGet class.
  • We need to provide the list of primary keys.
  • When you call the Execute method, the response returns the elements of the Result property.

Get items from multiple tables

Follow these steps to retrieve items from multiple tables:

(Video) An Introduction to AWS DynamoDB (Accessing DynamoDB data from .NET Core AWS Lambda Function)

  • First, create an instance of CreateBatchGet type for each type and pass in the primary key values ​​you want to retrieve from each table.
  • Create an instance of in one of the following waysMultiTableBatchGetclass: - Call the Combine function using one of the BatchGet objects you created in the previous step. - A list of BatchGet objects is used to create an instance of the MultiBatchGet type. - Pass your list of BatchGet objects to DynamoDBContext's CreateMultiTableBatchGet function.
  • Call the Execute function of MultiTableBatchGet, which provides results written to individual BatchGet objects.

HeCreateBatchGetThe function is used in the following C# code to retrieve various items from the Employee and EmployeeWorkDetails databases.

Guerraemployee batch=context.CreateBatchGet <Employees> ();employee batch.add key(101);employee batch.add key(102);GuerraEmployeeJobDetailsLot=context.CreateBatchGet <Employee Job Details> ();EmployeeJobDetailsLot.add key(101, "P1");EmployeeJobDetailsLot.add key(101, "P2");EmployeeJobDetailsLot.add key(102, "P3");EmployeeJobDetailsLot.add key(102, "P1");GuerraEmployeesAndDetailSuperBatch=Employee Job Details.To combine(Employee Job Details);EmployeesAndDetailSuperBatch.Accomplish();console.Write line(employee batch.Results.To count);console.Write line(EmployeeJobDetailsLot.Results.To count);Employeesemp1=employee batch.Results[0];Employeesemp2=EmployeeJobDetailsLot.Results[1];EmployeeWorkDetailEmployeeWorkDetail=EmployeeJobDetailsLot.Results[0];

Batch write items

This section covers inserting and removing multiple items in a batch write operation. To insert or delete batch write, you need to pay attention to the following.

  • First, call the CreateBatchWrite method on DynamoDB and create the BatchWrite class.
  • Mention the items you need to add or remove. For this:
    • When inserting items, use the AddPutItem method or the AddPutItems method.
    • When you delete an item, you must specify the item's primary key or the client-side object associated with the item you want to delete. Use the AddDeleteItem, AddDeleteItems, and AddDeleteKey methods to specify the list of items to delete.
    • You can call BatchWrite.Execute, a method to insert or delete specific items in the table.
DynamoDBContextcontext= nuevo DynamoDBContext(Client);Guerralot of books=context.CreateBatchWrite <Employees> ();// Specify the employee to addEmployeesemp1= nuevo Employees {EmpId= 101,employee category= "Internal",Description= "Inside Employee 1"};Employeesemp2= nuevo Employees {EmpId= 102,employee category= "Internal",Description= "Inside Employee 2"};lot of books.Add sale items(nuevo List<Employees> {emp1,emp2});// Specify the employee to deleteemployee batch.AddDeleteKey(111);employee batch.Accomplish();

execute transactions

The following code snippet illustrates how transactions are performed in DynamoDB.

collection<TransactWriteItem>Behavior=arrangements.like a list( nuevo TransactWriteItem().mitConditionCheck(checkMitarbeiterValid), nuevo TransactWriteItem().mitUpdate(markItemSale), nuevo TransactWriteItem().mitPut(create order));TransactWriteItemsRequestplaceOrderTransaction= nuevo TransactWriteItemsRequest() .mitTransactItems(Behavior) .mitReturnConsumedCapacity(Return used capacity.TOTAL);// Execute the transaction and process the result.attempt {Client.transactWriteItems(placeOrderTransaction);System.outside.print("Succesful transaction");} catch (ResourceNotFoundExceptionrnf) {System.err.print("Could not find one of the tables involved in the transaction" +rnf.get message());} catch (InternalServerErrorExceptionwhile) {System.err.print("Internal Server Error" +while.get message());} catch (TransactionCanceledExceptiontce) {System.outside.print("Transaction canceled" +tce.get message());}

Run DynamoDB Local

By default, .NET Core loads app settings from a specific stream of sources. In our situation, when the program starts in the development environment (which is the default when debugging Visual Studio), the settings in this additional JSON file override the previous settings. For example, LocalMode was set to true and the service URL for the local DynamoDB instance was added.

We chose the value http://localhost:8000, but you can change this if you want to run the container on a different host port.

The following code shows how to register the DynamoDB service.

public Empty configure services(IServiceCollectionIServiceCollectionServices) { GuerradinamoDbConfig=Construction.GetSection("DinamoDb"); GuerrarunLocalDynamoDb=dinamoDbConfig.receive value < bool > ("local operation"); And (runLocalDynamoDb) {Services.add singleton <AmazonDynamoDB> (sp=> { GuerraclientConfig= nuevo AmazonDynamoDBConfig {service url=dinamoDbConfig.receive value < line > ("local service url") }; go back nuevo AmazonDynamoDB client(clientConfig); }); } Anders {Services.Add AWS service <AmazonDynamoDB> (); }Services.add mvc().Set Compatibility Version(compatibility version.Version_2_1);}

We can manually register a service for theAmazonDynamoDBinterface if thelocal operationIt's true. We use the overload to provide an implementation factory, which in this case returns the actual implementation. we use thatlocal service urlfrom configuration to creating an AmazonDynamoDBConfig instance in our scenario. We then use this configuration to create and return the AmazonDynamoDBClient. We've set this up as a singleton, which means this code will only be executed once when the service is in use.

(Video) 8. AWS DynamoDB: Backups, Reserved Capacity and Preferences

If LocalMode is false, we need to use the AWS SDK helper methodAdd AWS serviceto add the service because we added thoseAWSSDK.Extensions.NETCore.ConfigurationPackage.

If you want to see your tables and local data in them, you can useDynobase to query and change items in spreadsheets offline.

learn more aboutRun DynamoDB locally.


How do I write a Query in DynamoDB? ›

You can use Query with any table or secondary index. You must specify an equality condition for the partition key's value, and you can optionally provide another condition for the sort key attribute if it is defined. The KeyConditionExpression parameter specifies the key values that you want to query.

How to connect to DynamoDB in C#? ›

Tutorial: DynamoDB with C# in . NET Core
  1. Nuget Packages. AWSSDK Amazon DynamoDB (“Install-Package AWSSDK.DynamoDBv2”) ...
  2. Set Your AWS Credentials. ...
  3. Verify Your Table. ...
  4. Create a New Table. ...
  5. Wait for Table to Create / Become Active. ...
  6. Set your DynamoDBContext. ...
  7. Save Something. ...
  8. Get Something.
Mar 21, 2017

What is the maximum size of DynamoDB Query? ›

The maximum item size in DynamoDB is 400 KB, which includes both attribute name binary length (UTF-8 length) and attribute value lengths (again binary length). The attribute name counts towards the size limit.

Is DynamoDB good for Query? ›

Since DynamoDB is a NoSQL data model, it handles less structured data more efficiently than a relational data model, which is why it's easier to address query volumes and offers high performance queries for item storage in inconsistent schemas.

Can you Query DynamoDB without primary key? ›

Hash key in DynamoDB

The primary reason for that complexity is that you cannot query DynamoDB without the hash key. So, it's not allowed to query the entire database. That means you cannot do what you would call a full table scan in other databases.

How to query multiple values in DynamoDB? ›

To query an item on multiple attributes without filter expressions, you must create a new global secondary index (GSI) with a new attribute as the partition key that contains the concatenation of the attributes for your query.

How do you write a database query? ›

How to Create a SQL Statement
  1. Start your query with the select statement. select [all | distinct] ...
  2. Add field names you want to display. field1 [,field2, 3, 4, etc.] ...
  3. Add your statement clause(s) or selection criteria. Required: ...
  4. Review your select statement. Here's a sample statement:
Oct 13, 2022

How to use DynamoDB in .NET core? ›

  1. Step 1: Create a DynamoDB table in the AWS account. ...
  2. Step 2: Create an ASP.NET Core project. ...
  3. Step 3: Install NuGet packages for DynamoDB. ...
  4. Step 4: Load AWS credentials in SDK. ...
  5. Step 5: Configure Dependency Injection in Program. ...
  6. Step 6: Create a domain class that maps to the DynamoDB table.
Feb 27, 2022

How do I query local DynamoDB? ›

To access DynamoDB running locally, use the --endpoint-url parameter. The following is an example of using the AWS CLI to list the tables in DynamoDB on your computer. The AWS CLI can't use the downloadable version of DynamoDB as a default endpoint. Therefore, you must specify --endpoint-url with each AWS CLI command.

How do I access DynamoDB programmatically? ›

Get the AWS access Key (used to access DynamoDB programmatically).
Creating AWS account:
  1. Click on the “Get Started with Amazon DynamoDB” button, or the “Create an AWS Account” button.
  2. Fill in the required information for account creation.
  3. Choose the plan that best suits you and you are good to go.
Aug 19, 2021

How can I make DynamoDB query faster? ›

You can increase your DynamoDB throughput by several times, by parallelizing reads/writes over multiple partitions. Use DynamoDB as an attribute store rather than as a document store. This will not only reduce the read/write costs but also improve the performance of your operations considerably.

How fast is DynamoDB query? ›

DynamoDB offers 40,000 WCUs per second (depending on the region), indicating that the table can handle 40,000 writes per second for items of 1KB in size. DynamoDB will throttle the requests when the write throughput exceeds and cause latency. You can increase that if needed.

How many writes can DynamoDB handle? ›

Each partition on a DynamoDB table is subject to a hard limit of 1,000 write capacity units and 3,000 read capacity units. If the workload is unevenly distributed across partitions, or if the workload relies on short periods of time with high usage (a burst of read or write activity), the table might be throttled.

How to Query large data from DynamoDB? ›

During our engagements with customers, we often need to retrieve a large number of records from DynamoDB databases.
Run the subqueries in parallel to build the data stream.
  1. Call the sub-query for each query parameter.
  2. Flatten the subquery results into a single stream of all orders.
  3. Collect the results.
Apr 4, 2022

Is DynamoDB SQL or NoSQL? ›

DynamoDB is a proprietary NoSQL database by Amazon that supports key-value and document data offered via the Amazon Web Services. This AWS cloud-only offering provides a scalable, highly available, and secure managed database platform for any application.

What query language does DynamoDB use? ›

Amazon DynamoDB supports PartiQL , a SQL-compatible query language, to select, insert, update, and delete data in Amazon DynamoDB.

Can we have 2 partition keys in DynamoDB? ›

Can a DynamoDB table have multiple partition keys? While you can only have a single partition key per DynamoDB table, you can create global indexes that have a different partition key than the table itself. This is useful if you want to query your data in a different way than the primary table.

Does DynamoDB Query return all items? ›

A Scan operation in Amazon DynamoDB reads every item in a table or a secondary index. By default, a Scan operation returns all of the data attributes for every item in the table or index. You can use the ProjectionExpression parameter so that Scan only returns some of the attributes, rather than all of them.

Can you Query multiple keys in DynamoDB? ›

Querying is a very powerful operation in DynamoDB. It allows you to select multiple Items that have the same partition ("HASH") key but different sort ("RANGE") keys.

How do you write a query formula? ›

The format of a formula that uses the QUERY function is =QUERY(data, query, headers) . You replace “data” with your cell range (for example, “A2:D12” or “A:D”), and “query” with your search query. The optional “headers” argument sets the number of header rows to include at the top of your data range.

How do you write a query function? ›

QUERY function
  1. data - The range of cells to perform the query on. Each column of data can only hold boolean, numeric (including date/time types) or string values. ...
  2. headers - [ OPTIONAL ] - The number of header rows at the top of data . If omitted or set to -1 , the value is guessed based on the content of data .

How do I query data from two tables? ›

To do so, we need to use join query to get data from multiple tables.
Example syntax to select from multiple tables:
  1. SELECT p. p_id, p.cus_id, p.p_name, c1.name1, c2.name2.
  2. FROM product AS p.
  3. LEFT JOIN customer1 AS c1.
  4. ON p.cus_id=c1.cus_id.
  5. LEFT JOIN customer2 AS c2.
  6. ON p.cus_id = c2.cus_id.

Which SQL command would you use to find multiple values in a query? ›

The IN operator allows you to specify multiple values in a WHERE clause. The IN operator is a shorthand for multiple OR conditions.

How many reads per second DynamoDB? ›

Transactional read requests require two read capacity units to perform one read per second for items up to 4 KB. If you need to read an item that is larger than 4 KB, DynamoDB must consume additional read capacity units.

How many requests per second can DynamoDB handle? ›

DynamoDB can handle more than 10 trillion requests per day and can support peaks of more than 20 million requests per second.

What is query give an example? ›

Query is another word for question. In fact, outside of computing terminology, the words "query" and "question" can be used interchangeably. For example, if you need additional information from someone, you might say, "I have a query for you." In computing, queries are also used to retrieve information.

What is query in database with example? ›

A query can either be a request for data results from your database or for action on the data, or for both. A query can give you an answer to a simple question, perform calculations, combine data from different tables, add, change, or delete data from a database.

How do I practice DynamoDB? ›

Getting started with DynamoDB
  1. Basic concepts in DynamoDB.
  2. Prerequisites - getting started tutorial.
  3. Step 1: Create a table.
  4. Step 2: Write data to a table using the console or AWS CLI.
  5. Step 3: Read data from a table.
  6. Step 4: Update data in a table.
  7. Step 5: Query data in a table.
  8. Step 6: Create a global secondary index.

How to retrieve data from DynamoDB? ›

Open the DynamoDB console at https://console.aws.amazon.com/dynamodb/ .
  1. In the navigation pane on the left side of the console, choose Tables.
  2. Choose the Music table from the table list.
  3. Select the View items.
  4. On the Items tab, view the list of items stored in the table, sorted by Artist and SongTitle .

Is DynamoDB easy? ›

DynamoDB is really easy to set up. We will utilize the settings and features available in the AWS Free Tier here, so you are able to recreate a comparable version if you're just getting started. To make a NoSQL table, follow these steps. Select Create Table from the DynamoDB console.

How to view data in DynamoDB? ›

Open the DynamoDB console at https://console.aws.amazon.com/dynamodb/ . In the navigation pane, choose Tables. In the list of tables, choose Reply. Choose the Explore items tab to view the data that you loaded into the table.

What is the difference between Query and get in DynamoDB? ›

getItem retrieve via hash and range key is a 1:1 fit, the time it takes (hence performance) to retrieve it is limited by the hash and sharding internally. Query results in a search on "all" range keys. It adds computational work, thus considered slower.

What is difference between scan and Query in DynamoDB? ›

DynamoDB offers two ways to access information stored: Query and Scan. A Query will rely on the primary-key to find information. Query can point directly to a particular item (or set ot items) and retrieve them in a fast and efficient way. Scan, as the name suggests, will browse table items from start to finish.

How to get data from DynamoDB using REST API? ›

  1. Step 1: Create a DynamoDB table. You use a DynamoDB table to store data for your API. ...
  2. Step 2: Create a Lambda function. You create a Lambda function for the backend of your API. ...
  3. Step 3: Create an HTTP API. ...
  4. Step 4: Create routes. ...
  5. Step 5: Create an integration. ...
  6. Step 6: Attach your integration to routes. ...
  7. Step 7: Test your API.

How to connect to DynamoDB database? ›

Create a DynamoDB connection
  1. From the Analytics main menu, select Import > Database and application.
  2. From the New Connections tab, in the ACL Connectors section, select DynamoDB. Tip. ...
  3. In the Data Connection Settings panel, enter the connection settings and at the bottom of the panel, click Save and Connect.

How do I connect to DynamoDB from a container? ›

If your local network on Docker is up and running we can go ahead and connect Workbench to our network.
  1. From the Operations Builder menu, select Add connection.
  2. Select DynamoDB local in the popup screen.
  3. Name your connection (anything you want)
  4. Select the port (default 8000)
  5. Hit Connect.
Jan 31, 2022

Is S3 faster than DynamoDB? ›

2) Amazon S3 vs DynamoDB: Purpose

For relatively small items, especially those with a size of less than 4 KB, DynamoDB runs individual operations faster than Amazon S3. DynamoDB can scale on-demand, but S3 offers better scalability.

Which is faster scan or query in DynamoDB? ›

For faster response times, design your tables and indexes so that your applications can use Query instead of Scan . (For tables, you can also consider using the GetItem and BatchGetItem APIs.)

How can I improve my query response time? ›

Here are some preferred practices that many data server technology vendors suggest to improve run-time performance.
  1. Avoid complex join and filter expressions. ...
  2. Reduce explicit or implicit data type conversions. ...
  3. Avoid using SQL expressions to transpose values. ...
  4. Avoid unnecessary outer joins.

How much does it cost for a Query in DynamoDB? ›

DynamoDB Streams are charged at $0.02 per 100,000 read operations. Data requested by requesters outside the AWS region where the DynamoDB table is deployed is charged at $0.09 per GB.

Is DynamoDB hard? ›

Designing a DynamoDB-backed Architecture is Not Easy

DynamoDB may be simple to interact with, but a DynamoDB-backed architecture is absolutely not simple to design. DynamoDB is a key-value store. It works really well if you are retrieving individual records based on key lookups.

How long does it take to learn DynamoDB? ›

Start with an interactive knowledge check, and after you've completed the courses, take the post-assessment to see what you've learned. Duration: 16 hours, optional self-paced labs: 9 hours. There are optional (paid) labs associated with each course.

What is the limit of DynamoDB query? ›

A single Query operation can retrieve a maximum of 1 MB of data. This limit applies before any FilterExpression or ProjectionExpression is applied to the results. If LastEvaluatedKey is present in the response and is non-null, you must paginate the result set (see Paginating table query results).

What is the limit size of DynamoDB query? ›

For more information on expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide. Value Length Constraints: Maximum length of 65535.

What is the max DynamoDB table size? ›

For a table with one or more LSIs, no item collection (including all base table items and all projected LSI views which have the same value of the partition key attribute) can exceed 10GB in size. This is because 10GB is the maximum size of a partition.

How do I get items from DynamoDB table? ›

Retrieving an item in DynamoDB requires using GetItem, and specifying the table name and item primary key. Be sure to include a complete primary key rather than omitting a portion. For example, omitting the sort key of a composite key. It executes as an eventually consistent read.

How do I get data from AWS DynamoDB? ›

Open the DynamoDB console at https://console.aws.amazon.com/dynamodb/ .
In the Scan or query items pane, do the following:
  1. Select the Query operation.
  2. In the id (Partition key) box, enter the value Amazon DynamoDB#DynamoDB Thread 1 .
  3. Choose Run. Only the items that match your query criteria are returned.

How do I Query local DynamoDB? ›

To access DynamoDB running locally, use the --endpoint-url parameter. The following is an example of using the AWS CLI to list the tables in DynamoDB on your computer. The AWS CLI can't use the downloadable version of DynamoDB as a default endpoint. Therefore, you must specify --endpoint-url with each AWS CLI command.

How do I connect to DynamoDB table? ›

Create a DynamoDB connection
  1. From the Analytics main menu, select Import > Database and application.
  2. From the New Connections tab, in the ACL Connectors section, select DynamoDB. Tip. ...
  3. In the Data Connection Settings panel, enter the connection settings and at the bottom of the panel, click Save and Connect.

Which is the fastest way to retrieve data from DynamoDB? ›

GetItem – Retrieves a single item from a table. This is the most efficient way to read a single item because it provides direct access to the physical location of the item. (DynamoDB also provides the BatchGetItem operation, allowing you to perform up to 100 GetItem calls in a single operation.)

Does DynamoDB query return all items? ›

A Scan operation in Amazon DynamoDB reads every item in a table or a secondary index. By default, a Scan operation returns all of the data attributes for every item in the table or index. You can use the ProjectionExpression parameter so that Scan only returns some of the attributes, rather than all of them.

How do I scan an entire table in DynamoDB? ›

In SQL, you can scan a table and retrieve all of its data by using a SELECT statement without specifying a WHERE clause. You can request one or more columns in the result. Or you can request all of them if you use the wildcard character (*). The following are examples of using a SELECT statement.

Does DynamoDB store data in JSON? ›

You can store a JSON document as an attribute in a DynamoDB table. To do this, use the withJSON method of Item . This method parses the JSON document and maps each element to a native DynamoDB data type.

What is the best way to search DynamoDB? ›

The easiest way to configure a search domain to search DynamoDB data is to use the Amazon CloudSearch console. The console's configuration wizard analyzes your table data and suggests indexing options based on the attributes in the table.

How fast is Query in DynamoDB? ›

DynamoDB offers 40,000 WCUs per second (depending on the region), indicating that the table can handle 40,000 writes per second for items of 1KB in size. DynamoDB will throttle the requests when the write throughput exceeds and cause latency. You can increase that if needed.

How is data stored in a DynamoDB table? ›

Amazon DynamoDB stores data in partitions. A partition is an allocation of storage for a table, backed by solid state drives (SSDs) and automatically replicated across multiple Availability Zones within an AWS Region.

Can you join two tables in DynamoDB? ›

Since DynamoDB is a NoSQL database, it does not allow you to perform "join" queries on multiple tables. A join requires the DMBS to scan several tables and perform complex processing to aggregate the data to return a result set. DynamoDB was built to provide quick, single-digit responses no matter how big the dataset.

Can I use SQL in DynamoDB? ›

DynamoDB can manage structured or semistructured data, including JSON documents. SQL is the standard for storing and retrieving data. Relational databases offer a rich set of tools for simplifying the development of database-driven applications, but all of these tools use SQL.


1. 21 Demo AWS NoSQL DynamoDB
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2. Serverless .NET Patterns: DynamoDB for Fun and Glory!
3. How to Query your DynamoDB tables with Serverless
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4. AWS DynamoDB Tutorial For Beginners
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5. AWS DynamoDB | Simple Operations| Create, Insert, Query and Delete the DynamoDB Table | Qwiklabs
6. Working with DynamoDB using Python (Hash Key, Range Key and Indexes Explained)
(Indian Pythonista)
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