Create a Data Access Object for Snowflake Data using JDBI

JDBI is a SQL convenience library for Java that exposes two different style APIs, a fluent style and a SQL object style. The CData JDBC Driver for Snowflake integrates connectivity to live Snowflake data in Java applications. By pairing these technologies, you gain simple, programmatic access to Snowflake data. This article explains how to build a basic Data Access Object (DAO) and the accompanying code to read and write Snowflake data.

Getting Started

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Create a DAO for the Snowflake Products Entity

The interface below declares the desired behavior for the SQL object to create a single method for each SQL statement to be implemented.

public interface MyProductsDAO {
 //insert new data into Snowflake
 @SqlUpdate("INSERT INTO Products (Id, ProductName) values (:id, :productName)")
 void insert(@Bind("id") String id, @Bind("productName") String productName);

 //request specific data from Snowflake (String type is used for simplicity)
 @SqlQuery("SELECT ProductName FROM Products WHERE Id = :id")
 String findProductNameById(@Bind("id") String id);

 /*
 * close with no args is used to close the connection
 */
 void close();
}

Open a Connection to Snowflake

Collect the necessary connection properties and construct the appropriate JDBC URL for connecting to Snowflake.

To connect to Snowflake:

1. Set User and Password to your Snowflake credentials and set the AuthScheme property to PASSWORD or OKTA.
2. Set URL to the URL of the Snowflake instance (i.e.: https://myaccount.snowflakecomputing.com).
3. Set Warehouse to the Snowflake warehouse.
4. (Optional) Set Account to your Snowflake account if your URL does not conform to the format above.
5. (Optional) Set Database and Schema to restrict the tables and views exposed.
6. (Optional) If MFA is enabled on your Snowflake account (via Duo Security), set MFACode to the passcode generated by your Duo authenticator app.

See the Getting Started guide in the CData driver documentation for more information.

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the Snowflake JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.snowflake.jar

Fill in the connection properties and copy the connection string to the clipboard.

👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)

A connection string for Snowflake will typically look like the following:

jdbc:snowflake:Authscheme=Password;URL=https://myaccount.snowflakecomputing.com;User=Admin;Password=test123;Server=localhost;Database=Northwind;Warehouse=TestWarehouse;Account=Tester1;MFACode=YourMFACode

Use the configured JDBC URL to obtain an instance of the DAO interface. The particular method shown below will open a handle bound to the instance, so the instance needs to be closed explicitly to release the handle and the bound JDBC connection.

DBI dbi = new DBI("jdbc:snowflake:Authscheme=Password;URL=https://myaccount.snowflakecomputing.com;User=Admin;Password=test123;Server=localhost;Database=Northwind;Warehouse=TestWarehouse;Account=Tester1;MFACode=YourMFACode");
MyProductsDAO dao = dbi.open(MyProductsDAO.class);

//do stuff with the DAO

dao.close();

Read Snowflake Data

With the connection open to Snowflake, simply call the previously defined method to retrieve data from the Products entity in Snowflake.

//disply the result of our 'find' method
String productName = dao.findProductNameById("1");
System.out.println(productName);

Write Snowflake Data

It is also simple to write data to Snowflake, using the previously defined method.

//add a new entry to the Products entity
dao.insert(newId, newProductName);

Since the JDBI library is able to work with JDBC connections, you can easily produce a SQL Object API for Snowflake by integrating with the CData JDBC Driver for Snowflake. Download a free trial and work with live Snowflake data in custom Java applications today.