Migrating data from REST to Databricks using CData SSIS Components.

Easily push REST data to Databricks using the CData SSIS Tasks for REST and Databricks.

Databricks is a unified data analytics platform that allows organizations to easily process, analyze, and visualize large amounts of data. It combines data engineering, data science, and machine learning capabilities in a single platform, making it easier for teams to collaborate and derive insights from their data.

The CData SSIS Components enhance SQL Server Integration Services by enabling users to easily import and export data from various sources and destinations.

In this article, we explore the data type mapping considerations when exporting to Databricks and walk through how to migrate REST data to Databricks using the CData SSIS Components for REST and Databricks.

Data Type Mapping

Databricks Schema	CData Schema
int, integer, int32	int
smallint, short, int16	smallint
double, float, real	float
date	date
datetime, timestamp	datetime
time, timespan	time
string, varchar	If length > 4000: nvarchar(max), Otherwise: nvarchar(length)
long, int64, bigint	bigint
boolean, bool	tinyint
decimal, numeric	decimal
uuid	nvarchar(length)
binary, varbinary, longvarbinary	binary(1000) or varbinary(max) after SQL Server 2000

Special Considerations

String/VARCHAR: String columns from Databricks can map to different data types depending on the length of the column. If the column length exceeds 4000, then the column is mapped to nvarchar (max). Otherwise, the column is mapped to nvarchar (length).
DECIMAL Databricks supports DECIMAL types up to 38 digits of precision, but any source column beyond that can cause load errors.

Prerequisites

Visual Studio 2022
SQL Server Integration Services Projects extension for Visual Studio 2022
CData SSIS Components for Databricks
CData SSIS Components for REST

Create the project and add components

Open Visual Studio and create a new Integration Services Project.
Add a new Data Flow Task to the Control Flow screen and open the Data Flow Task.
Add a CData REST Source control and a CData Databricks Destination control to the data flow task.

Configure the REST source

Follow the steps below to specify properties required to connect to REST.

Double-click the CData REST Source to open the source component editor and add a new connection.
In the CData REST Connection Manager, configure the connection properties, then test and save the connection.
See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models REST APIs as bidirectional database tables and XML/JSON files as read-only views (local files, files stored on popular cloud services, and FTP servers). The major authentication schemes are supported, including HTTP Basic, Digest, NTLM, OAuth, and FTP. See the Getting Started chapter in the data provider documentation for authentication guides.

After setting the URI and providing any authentication values, set Format to "XML" or "JSON" and set DataModel to more closely match the data representation to the structure of your data.

The DataModel property is the controlling property over how your data is represented into tables and toggles the following basic configurations.
- Document (default): Model a top-level, document view of your REST data. The data provider returns nested elements as aggregates of data.
- FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
- Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.
See the Modeling REST Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.
After saving the connection, select "Table or view" and select the table or view to export into Databricks, then close the CData REST Source Editor.

Configure the Databricks destination

With the REST Source configured, we can configure the Databricks connection and map the columns.

Double-click the CData Databricks Destination to open the destination component editor and add a new connection.
In the CData Databricks Connection Manager, configure the connection properties, then test and save the connection. To connect to a Databricks cluster, set the properties as described below.
Note: The needed values can be found in your Databricks instance by navigating to Clusters, selecting the desired cluster, and selecting the JDBC/ODBC tab under Advanced Options.
- Server: Set to the Server Hostname of your Databricks cluster.
- HTTPPath: Set to the HTTP Path of your Databricks cluster.
- Token: Set to your personal access token (this value can be obtained by navigating to the User Settings page of your Databricks instance and selecting the Access Tokens tab).
Other helpful connection properties
- QueryPassthrough: When this is set to True, queries are passed through directly to Databricks.
- ConvertDateTimetoGMT: When this is set to True, the components will convert date-time values to GMT, instead of the local time of the machine.
- UseUploadApi: Setting this property to true will improve performance if there is a large amount of data in a Bulk INSERT operation.
- UseCloudFetch: This option specifies whether to use CloudFetch to improve query efficiency when the table contains over one million entries.
After saving the connection, select a table in the Use a Table menu and in the Action menu, select Insert.
On the Column Mappings tab, configure the mappings from the input columns to the destination columns.