Amazon DynamoDB

Last modified: April 18, 2024

1 Introduction

The Amazon DynamoDB connector provides a way for you to increase the security, scalability, and performance of your Mendix app by implementing Amazon DynamoDB.

1.1 Typical Use Cases

Amazon DynamoDB helps improve your app by giving you the tools to build scalable, performant applications on a flexible, serverless database. You can use it to develop high-traffic online platforms and applications for a variety of modern industries, such as content streaming, electronic commerce, or gaming.

1.2 Prerequisites

The Amazon DynamoDB connector requires Mendix Studio Pro 9.18.0 or above.

To use the Amazon DynamoDB connector, you must also install and configure the following modules:

AWS Authentication connector version 2.0 or higher - This connector is required to authenticate with Amazon Web Services (AWS). It is crucial for the Amazon DynamoDB connector to function correctly. If you are using the Amazon DynamoDB connector version 2.0 or higher, it requires the AWS Authentication connector version 3.0 or higher. It is crucial for the Amazon S3 connector to function correctly. For more information about installing and configuring the AWS Authentication connector, see AWS Authentication.
Community Commons module - This module is required to parse the creationDateTime attribute as returned by the DescribeTable activity.

1.3 Licensing and Cost

This connector is available as a free download from the Mendix Marketplace, but the AWS service to which is connects may incur a usage cost. For more information, refer to AWS documentation.

Most AWS services provide a free tier that allows easy access to most services. To find out if this service is included in the free tier, see AWS Free Tier. To calculate the potential cost of using an AWS service outside of the free tier, use the AWS Cost calculator.

Depending on your use case, your deployment environment, and the type of app that you want to build, you may also need a license for your Mendix app. For more information, refer to Licensing Apps.

2 Installation

Follow the instructions in Using Marketplace Content to import the Amazon DynamoDB connector into your app.

3 Configuration

After you install the connector, you can find it in the App Explorer, in the AmazonDynamoDBConnector section. The connector provides a domain model and several activities that you can use to connect your app to Amazon DynamoDB. Each activity can be implemented by using it in a microflow. To ensure that your app can connect to the AWS service, you must also configure AWS authentication for the connector.

3.1 Configuring AWS Authentication

In order to use the Amazon DynamoDB service, you must authenticate with AWS. To do so, you must set up a configuration profile in your Mendix app. After you set up the configuration profile, the connector module handles the authentication internally.

As of version 3.0.0 of the AWS Authentication Connector, all the resources and logic required to set up authentication are centralized inside the AWS Authentication Connector module.

The AWS Authentication Connector supports both static credentials and temporary credentials. For more information and detailed instructions please refer to the AWS Authentication Connector documentation page.

3.2 Configuring a Microflow for an AWS Service

After you configure the authentication profile for Amazon DynamoDB, you can implement the functions of the connector by using the provided activities in microflows. For example, to list all Amazon DynamoDB tables for a specific region, implement the ListTables activity by doing the following steps:

In the App Explorer, find and open the domain model for your app.
Right-click on the working area of the domain model, and then click Add entity.
Open the new entity by double-clicking on it.
Enter a name for the entity, for example, DBTable.
In the Attributes section, click New, and then configure the attribute in the following way:
- Name - A unique name for the attribute, for example, TableName
- Type - String
The parameters that you need to configure depend on the contents of the response that an activity expects. The ListTables activity used in this example only expects the database table name as a response. Other activities require different parameters. For more information, see Activities.
In the App Explorer, right-click on the name of your module, and then click Add microflow.
Enter a name for your microflow, for example, DS_ListTables, and then click OK.
In the App Explorer, in the AmazonDynamoDBConnector > Operations section, find the ListTables activity.
Drag the ListTables activity onto the work area of your microflow.
In the Properties pane for the microflow, in the Security section, select a user role that should be allowed to run the microflow.
Double-click the ListTables activity to configure the required parameters.

For the ListTables activity, you must specify the region for which you want to retrieve the tables from, a Credentials object and a ListTablesRequest object. Other activities may have different required parameters.
Click Edit parameter value, edit the ENUM_Region parameter, and change Type to Expression.
In the expression builder, type ENUM_Region, and then press Ctrl+Space.
In the autocomplete dialog, select AWSAuthentication.ENUM_Region, then type . and select your AWS region from the list.
Click OK, and then click OK again.
In the App Explorer, in the AWSAuthentication > ConnectionDetails section, find the GetStaticCredentials and GetTemporaryCredentials actions.
Drag the one you would like to use onto the microflow you are working on, and position it between the microflow start event and the ListTables activity.
Double-click the microflow action and then configure the required ENUM_Region parameter in the same way as described in step 5.
Double-click the ListTables activity and configure the Credentials parameter by doing the following steps:
- Click Edit parameter value.
- Edit the Credentials parameter and let it auto-fill.
In the Toolbox pane, search for the Create Object activity, drag it onto the microflow area, and position it between the GetStaticCredentials or GetTemporaryCredentials and the ListTables activity.
Double-click the Create Object activity, and then select AmazonDynamoDBConnector.ListTablesRequest as the entity.
Double-click the CreateBucket activity and configure the CreateBucketRequest parameter by doing the following steps:
- Click Edit parameter value.
- Edit the CreateBucketRequest parameter and let it auto-fill.
In the Toolbox pane, search for the Retrieve activity and drag it onto the microflow area.
Position the Retrieve activity between the ListTables activity and the microflow end event.
Double-click the Retrieve activity.
In the Association section, click Select.
In the Select Association dialog box, expand the Variable item, and then select ListTablesResponse as the association.
Click OK.
In the Toolbox pane, search for the Create list activity and drag it onto the microflow area.
Position the Create list activity between the microflow start event and the ListTables activity.
Double-click the Create list activity.
In the Entity section, click Select.
In the Select Entity dialog box, select the entity that you previously added to your domain model, for example, DBTable.
In the Toolbox pane, search for the Loop activity and drag it onto the microflow area.
Position the Loop activity before the microflow end event.
Double-click the Loop activity.
In the Iterate over list, select ListTableList.
In the Toolbox pane, search for the Create object activity and drag it inside the loop area.
Double-click the Create object activity.
In the Entity section, click Select.
In the Select Entity dialog box, select the entity that you previously added to your domain model, for example, DBTable, and then click Select.
In the Create Object dialog box, click New.
In the Edit Change Item dialog box, in the Member drop-down, select the attribute that you previously created, for example, TableName.
In the expression editor, type $IteratorListTable/TableName, and then click OK.
In the Toolbox pane, search for the Change List activity and drag it inside the loop area, to the right of the Create Object activity.
Double-click the Change List activity, and then set the following values:
- Type - Add
- Value - The created object, for example, $NewDBTable
Double-click the end event of your microflow, and then set the following values:
- Type - List
- Entity - The entity that you previously added to your domain model, for example, DBTable
Right-click the Create List activity, and then click Set {TableName} as return value.
In the App Explorer, right-click on the name of your module, and then click Add page.
In the Lists category, select the List template for the page.
Enter a name for your page, for example, Table_Overview, and then click OK.
On the page, double-click the List view widget.
In the Select Data Source dialog, set the Type to Microflow.
In the Microflow field, select the DS_ListTables microflow.
Click OK, and then click Yes.
In the Properties pane for the page, in the Navigation > Visible for section, select a user role that should be allowed to run the microflow.
In the App Explorer, double-click the Navigation for your app.
In the Menu section, click New Item.
In the New Menu Item dialog, configure the following settings:
- Caption - A caption for the navigation item, for example, Table
- Icon - An icon that will be displayed for this page in the navigation for your app
- On click - Show a page
- Page - Your Table_Overview page
Click OK.
Click Run Locally () to preview your app and validate your results. For more information, see Studio Pro Overview: Run and View App.

4 Technical Reference

To help you work with the Amazon DynamoDB connector, the following sections of this document list the available entities, enumerations, and activities that you can use in your application.

4.1 Domain Model

The domain model is a data model that describes the information in your application domain in an abstract way. For more information, see Domain Model.

4.1.1 AbstractItem

This generalization entity holds information of items inside Amazon DynamoDB. Each item represents a row in a table. Each item at least has one KeyValue object.

Name	Documentation
N/A	The `AbstractItem` entity has no attributes.

4.1.2 AbstractKey

Name	Documentation
`Key`

4.1.3 KeyValueString

Name	Documentation
`StringValue`	The `StringValue` attribute describes an attribute of type String.

4.1.4 KeyValueLong

Name	Documentation
`LongValue`	The `LongValue` attribute describes an attribute of type Long.

4.1.5 KeyValueDecimal

Name	Documentation
`DecimalValue`	The DecimalValue attribute describes an attribute of type Decimal.

4.1.6 KeyValueBoolean

Name	Documentation
`BooleanValue`	The `BooleanValue` attribute describes an attribute of type boolean.

4.1.7 DescribeTableRequest

Name	Documentation
`TableName`	The `TableName` attribute describes the table name and is a required parameter.

4.1.8 DescribeTableResponse

Name	Documentation
`ItemCount`	The `ItemCount` attribute describes the number of items in the specified table. DynamoDB updates this value approximately every six hours. Recent changes might not be reflected in this value.
`CreationDateTime`	The `CreationDateTime` attribute describes the date and time when the table was created, in UNIX epoch time format.
`TableARN`	The `TableARN` attribute describes the Amazon Resource Name (ARN) that uniquely identifies the table.
`TableId`	The `TableId` attribute describes the unique identifier for the table for which the backup was created.
`TableStatus`	The `TableStatus` attribute describes the current state of the table.
`TableName`	The `TableName` attribute describes the table name.

4.1.9 AttributeDefinition

Name	Documentation
`AttributeType`	The `AttributeType` attribute describes the data type for the attribute.

4.1.10 KeySchemaElement

Name	Documentation
`KeyType`	The `KeyType` attribute describes the role of the attribute.

4.1.11 DeleteItemRequest

Name	Description
`ConditionExpression`	The `ConditionExpression` attribute describes a condition that must be satisfied in order for a conditional `DeleteItem` to succeed.
`TableName`	The `TableName` attribute describes the table name and is a required parameter.

4.1.12 DeleteItem

Name	Description
N/A	Entity `DeleteItem` has no attributes, it inherits from `AbstractItem`.

4.1.13 ExpressionAttributeName

Name	Documentation
Placeholder	N/A

4.1.14 DeleteItemResponse

Name	Description
N/A	Entity `DeleteItemResponse` has no attributes.

4.1.15 ListTablesRequest

Name	Documentation
`ExclusiveStartTableName`	The `ExclusiveStartTableName` attribute describes the first table name that this operation will evaluate. Use the value that was returned for `LastEvaluatedTableName` in a previous operation, so that you can obtain the next page of results.
`Limit`	The `Limit` attribute describes a maximum number of table names to return. If this parameter is not specified, the limit is 100.

4.1.16 ListTablesResponse

Name	Documentation
`LastEvaluatedTableName`	The `LastEvaluatedTableName` attribute describes the name of the last table in the current page of results. Use this value as the `ExclusiveStartTableName` in a new request to obtain the next page of results, until all the table names are returned.

4.1.17 Table

Name	Documentation
`TableName`	The `TableName` attribute describes the table name.

4.1.18 BatchGetItemRequest

Name	Documentation
`isConsistentRead`	The `isConsistentRead` attribute describes the consistency of a read operation. If set to true, then a strongly consistent read is used; otherwise, an eventually consistent read is used.

4.1.19 RequestTable

Name	Documentation
`TableName`	The `TableName` attribute describes the table name and is a required parameter.
`ProjectionExpression`	The `ProjectionExpression` attribute describes a string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the `ProjectionExpression` must be separated by commas.

4.1.20 BatchGetRequestedItem

Name	Documentation
N/A	Entity `BatchGetRequestedItem` has no attributes, it inherits from `AbstractItem`.

4.1.21 BatchGetItemResponse

Name	Documentation
N/A	Entity `BatchGetItemResponse` has no attributes.

4.1.22 ResponseTable

Name	Documentation
`TableName`	The `TableName` attribute describes the table name.

4.1.23 BatchGetResponseItem

Name	Documentation
N/A	Entity `BatchGetResponseItem` has no attributes, it inherits from `AbstractItem`.

4.1.24 ScanRequest

Name	Documentation
`Limit`	The `Limit` attribute describes the maximum number of items to evaluate (not necessarily the number of matching items). If DynamoDB processes the number of items up to the limit while processing the results, it stops the operation and returns the matching values up to that point, and a key in LastEvaluatedKey to apply in a subsequent operation, so that you can pick up where you left off. Also, if the processed dataset size exceeds 1 MB before DynamoDB reaches this limit, it stops the operation and returns the matching values up to the limit, and a key in LastEvaluatedKey to apply in a subsequent operation to continue the operation.
`IndexName`	The `IndexName` attribute describes the name of a secondary index to scan. This index can be any local secondary index or global secondary index. Note that if you use the IndexName parameter, you must also provide TableName.
`TableName`	The `TableName` attribute describes the name of the table containing the requested items; or, if you provide the `IndexName`, the name of the table to which that index belongs and is a required parameter.

4.1.25 Condition

Name	Documentation
`ComparisonOperator`	The `ComparisonOperator` attribute describes a comparator for evaluating attributes. For example, equals, greater than, less than, etc. and is a required parameter.

4.1.26 ScanTableValueString

Name	Documentation
`StringValue`	The StringValue attribute describes an attribute of type String.

4.1.27 ScanTableValueDecimal

Name	Documentation
`DecimalValue`	The `DecimalValue` attribute describes an attribute of type Decimal.

4.1.28 ScanTableValueLong

Name	Documentation
`LongValue`	The LongValue attribute describes an attribute of type Long.

4.1.29 ScanTableValueBoolean

Name	Documentation
`BooleanValue`	The `BooleanValue` attribute describes an attribute of type Boolean.

4.1.30 ScanResponse

Name	Documentation
`TableName`	The `TableName` attribute describes the table name.

4.1.31 ScanItem

Name	Documentation
N/A	Entity `ScanItem` has no attributes, it inherits from `AbstractItem`.

4.1.32 BatchWriteItemRequest

Name	Documentation
N/A	Entity `BatchWriteItemRequest` has no attributes.

4.1.33 TableWithItemsToAdd

Name	Documentation
`TableName`	The `TableName` attribute describes the table name and is a required parameter.

4.1.34 ItemToAdd

Name	Documentation
N/A	Entity `ItemToAdd` has no attributes, it inherits from `AbstractItem`.

4.1.35 TableWithItemsToDelete

Name	Documentation
`TableName`	The `TableName` attribute describes the table name and is a required parameter.

4.1.36 ItemToDelete

Name	Documentation
N/A	Entity `ItemToDelete` has no attributes, it inherits from `AbstractItem`.

4.1.37 BatchWriteItemResponse

Name	Documentation
N/A	Entity `BatchWriteItemResponse` has no attributes.

4.1.38 GetItemRequest

Name	Documentation
`TableName`	The `TableName` attribute describes the table name and is a required parameter.
`isConsistentRead`	The `isConsistentRead` attribute describes the read consistency model. If set to true, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.

4.1.39 GetItem

Name	Documentation
N/A	Entity `GetItem` has no attributes, it inherits from `AbstractItem`.

4.1.40 GetItemResponse

Name	Documentation
N/A	Entity `GetItemResponse` has no attributes, it inherits from `AbstractItem`.

4.1.41 PutItemRequest

Name	Documentation
`TableName`	The `TableName` attribute describes the table name and is a required parameter.

4.1.42 PutItem

Name	Documentation
N/A	Entity `PutItem` has no attributes, it inherits from `AbstractItem`.

4.1.43 PutItemResponse

Name	Documentation
N/A	Entity `PutItemResponse` has no attributes.

4.2 Enumerations

An enumeration is a predefined list of values that can be used as an attribute type. For the Amazon DynamoDB connector, enumerations list values such as the status of database tables.

4.2.1 `ENUM_BooleanValue`

Name	Caption	Description
`_TRUE`	TRUE	The enumeration element if a key-value pair is of the type Boolean and is set to true
`_FALSE`	FALSE	The enumeration element if a key-value pair is of the type Boolean and is set to false

4.2.2 `ENUM_TableStatus`

Name	Caption	Description
`CREATING`	CREATING	The enumeration element that shows the status of a table that is being created
`UPDATING`	UPDATING	The enumeration element that shows the status of a table that is being updated
`DELETING`	DELETING	The enumeration element that shows the status of a table that is being deleted
`ACTIVE`	ACTIVE	The enumeration element that shows the status of a table that is active
`INACCESSIBLE_ENCRYPTION_CREDENTIALS`	INACCESSIBLE_ENCRYPTION_CREDENTIALS	The enumeration element that shows the status of a table that has an inaccessible AWS KMS key. Table operations may fail due to this

4.2.3 `ENUM_KEY`

Name	Caption	Description
`HASH`	HASH (partition)	The enumeration element that reflects the partition key of a table
`RANGE`	RANGE (sort)	The enumeration element that reflects the sort key of a table
`UNKNOWN_TO_SDK_VERSION`	UNKNOWN_TO_SDK_VERSION	The enumeration element that reflects an unknown key schema element

4.2.4 `ENUM_AttributeType`

Name	Caption	Description
`String`	String	The enumeration element that reflects native data type of string
`Number`	Number	The enumeration element that reflects native data type of a number (decimal or long)
`Binary`	Binary	The enumeration element that reflects native data type of a binary file expressed as a string

4.2.5 `ENUM_ComparisonOperator`

For more information on using comparison operators, please visit Amazon DynamoDB docs.

Name	Caption	Description
`BEGINS_WITH`	BEGINS_WITH	The enumeration element that evaluates items for a prefix
`BETWEEN`	BETWEEN	The enumeration element that evaluates items between two given items, where the first item must be smaller than the second
`CONTAINS`	CONTAINS	The enumeration element that evaluates items for a subsequence or value in a set
`EQ`	EQUAL	The enumeration element that evaluates items against an item. This comparison operator supports all data types, including lists and maps
`GE`	GREATER_THAN_OR_EQUAL	The enumeration element that evaluates whether items are greater than or equal to the key-value pair
`GT`	GREATER_THAN	The enumeration element that evaluates whether items are greater than the key-value pair
`IN`	IN	The enumeration element that evaluates whether items match elements in a list
`LE`	LESS_THAN_OR_EQUAL	The enumeration element that evaluates whether items are less than or equal to the key-value pair
`LT`	LESS_THAN	The enumeration element that evaluates whether items are less than the key-value pair
`NE`	NOT_EQUAL	The enumeration element that evaluates whether items are unequal to the key-value pair
`NOT_CONTAINS`	NOT_CONTAINS	The enumeration element that evaluates items for absence of a subsequence, or absence of a value in a set
`NOT_NULL`	NOT_NULL	The enumeration element that evaluates whether items are not null. This comparison operator supports all data types, including lists and maps
`_NULL`	NULL	The enumeration element that evaluates whether items have the attribute. This comparison operator supports all data types, including lists and maps

4.3 Activities

Activities define the actions that are executed in a microflow or a nanoflow. For the Amazon DynamoDB connector, they represent the actions that can be performed on DynamoDB database tables.

4.3.1 BatchGetItem

The BatchGetItem Amazon DynamoDB activity allows you to get multiple items from DynamoDB in a single call. It requires a valid AWS Region, a Credentials object and a BatchGetItemRequest object that contains the tables from which the item must be fetched. You must also specify whether the activity should perform a consistent read, and provide a list of keys to query from.