Joining and Inserting Data from Two Different Databases in Java

Discover how to effectively join data from two distinct databases and insert it into a Value Object (VO) in Java with practical examples.
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Joining and Inserting Data from Two Different Databases in Java: A Comprehensive Guide

In today's data-driven world, it's not uncommon to encounter situations where data is spread across multiple databases. This poses challenges when consolidating this data into a single format or object, especially in programming languages like Java. A common question developers face is, how can you join and insert data from two different databases into a Value Object (VO)?

Understanding the Problem

Imagine you have a university database setup where student information is stored in one database, and student access logs are kept in another. Your objective is to create a seamless transition that allows you to combine this data into a single StudentVO object. The unique identifier between the two databases in this case is STUD_LOG_ID.

Let's break down how to achieve this by considering an example query setup:

Database Schemas

Database 1 (Student Data):

[[See Video to Reveal this Text or Code Snippet]]

Database 2 (Student Access Data):

[[See Video to Reveal this Text or Code Snippet]]

Step-by-Step Solution

When approaching this problem, it's important to minimize database connections as each connection can be expensive. Below, we detail a solution that allows you to connect to two databases, retrieve records, and merge them based on a common identifier.

1. Setup Your Connection and Queries

First, establish a connection to the databases. The following example assumes you already have functions implemented to obtain a data source:

[[See Video to Reveal this Text or Code Snippet]]

2. Retrieve Data from Both Result Sets

Create two lists to hold the data from each query. Carefully iterate through each ResultSet and populate these lists:

[[See Video to Reveal this Text or Code Snippet]]

3. Match and Combine Data

Iterate through your retrieved data, checking for matches on STUD_LOG_ID. Create a new list that combines this information into a single StudentVO object.

[[See Video to Reveal this Text or Code Snippet]]

4. Store Consolidated Data

Once you have your finalList, you can easily store this consolidated information back to where it is needed. Assuming you have a StudentStore in place:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Joining and inserting data from two different databases in Java may seem complex at first, but by breaking it down into organized steps, it becomes much more manageable. Utilizing a single connection to minimize costs, efficiently iterating through your data, and carefully mapping it to your VO are essential steps to successfully achieving your goal.

This approach not only streamlines your process but also optimizes the performance of your application by reducing unnecessary connections and processing times.

By implementing the outlined strategy, you'll be well-equipped to handle similar data challenges in your Java projects!