Change Data Capture (CDC)

CDC (Change Data Capture) is a process that captures changes made to a database and records them in a separate location, such as a Kafka topic. Oracle and Kafka can be integrated to enable CDC by using a connector, such as the Oracle GoldenGate for Big Data Kafka Connector. This connector can capture changes from an Oracle database and stream them to a Kafka topic in real-time. 

There are several open-source CDC tools available for Oracle databases, some of which include:

Oracle LogMiner: This is a built-in tool provided by Oracle that can be used to extract changes from the redo log files.

Oracle GoldenGate: This is a popular open-source tool for real-time replication and data integration. It can be used to capture changes from an Oracle database and stream them to other databases or data sources.

Debezium: This is an open-source CDC tool that can capture changes from various databases, including Oracle, and stream them to Apache Kafka or other data streams.

OraCDC: This is an open-source tool that captures changes from an Oracle database and streams them to a variety of data sources, including Kafka.

Datasketches CDC: This is open-source tool for change data capture, replication, and data integration for Oracle databases.

These are just a few examples of open-source CDC tools for Oracle databases, and there may be others available as well. It's worth noting that some of these tools have different capabilities and may be better suited for certain use cases than others.

To implement CDC (Change Data Capture) using Kafka and Java, you would need to use a Kafka Connector that supports CDC, such as the Debezium Connector for Kafka. Here's an example of Java code that demonstrates how to use the Debezium Connector to capture changes from an Oracle database and stream them to a Kafka topic:

import org.apache.kafka.connect.source.SourceRecord;

import io.debezium.config.Configuration;

import io.debezium.connector.oracle.OracleConnector;

import io.debezium.embedded.EmbeddedEngine;

// Create the configuration for the Oracle connector

Configuration config = Configuration.create()

    .with("name", "oracle-connector")

    .with("connector.class", OracleConnector.class)

    .with("tasks.max", "1")

    .with("database.hostname", "oracle-host")

    .with("database.port", "1521")

    .with("database.user", "oracle-user")

    .with("database.password", "oracle-password")

    .with("database.dbname", "oracle-dbname")

    .with("database.server.name", "oracle-server")

    .with("database.history", "io.debezium.relational.history.FileDatabaseHistory")

    .with("database.history.file.filename", "/path/to/history/file")

    .with("topic.prefix", "oracle-")

    .build();

// Start the Debezium engine

EmbeddedEngine engine = EmbeddedEngine.create()

    .using(config)

    .notifying(this::handleEvent)

    .build();

engine.run();

// Handle events

private void handleEvent(SourceRecord record) {

    // Do something with the record, such as sending it to a Kafka topic

}

This code creates a configuration for the Oracle connector, starts the Debezium engine, and sets up a callback method (handleEvent) to handle the change events. The handleEvent method can then be used to send the change events to a Kafka topic or to perform other actions.

This is just one example of how to implement CDC with Kafka and Java, and the specific steps and code may vary depending on the connector you use and the requirements of your application.