[docs][oracle] Add an example of Incremental Snapshot based DataStrea…

…m for Oracle CDC Connector

This closes apache#2325.

Co-authored-by: skylines <[email protected]>

docs/content/connectors/oracle-cdc.md

@@ -469,7 +469,63 @@ The Oracle CDC source can't work in parallel reading, because there is only one
 
 ### DataStream Source
 
-The Oracle CDC connector can also be a DataStream source. You can create a SourceFunction as the following shows:
+The Oracle CDC connector can also be a DataStream source. There are two modes for the DataStream source:
+
+- incremental snapshot based, which allows parallel reading
+- SourceFunction based, which only supports single thread reading
+
+#### Incremental Snapshot based DataStream (Experimental)
+
+```java
+import com.ververica.cdc.connectors.base.options.StartupOptions;
+import com.ververica.cdc.connectors.base.source.jdbc.JdbcIncrementalSource;
+import com.ververica.cdc.connectors.oracle.source.OracleSourceBuilder;
+import com.ververica.cdc.debezium.JsonDebeziumDeserializationSchema;
+import org.apache.flink.api.common.eventtime.WatermarkStrategy;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+
+import java.util.Properties;
+
+public class OracleParallelSourceExample {
+
+    public static void main(String[] args) throws Exception {
+        Properties debeziumProperties = new Properties();
+        debeziumProperties.setProperty("log.mining.strategy", "online_catalog");
+        debeziumProperties.setProperty("log.mining.continuous.mine", "true");
+
+        JdbcIncrementalSource<String> oracleChangeEventSource =
+                new OracleSourceBuilder()
+                        .hostname("host")
+                        .port(1521)
+                        .databaseList("XE")
+                        .schemaList("DEBEZIUM")
+                        .tableList("DEBEZIUM.PRODUCTS")
+                        .username("username")
+                        .password("password")
+                        .deserializer(new JsonDebeziumDeserializationSchema())
+                        .includeSchemaChanges(true) // output the schema changes as well
+                        .startupOptions(StartupOptions.initial())
+                        .debeziumProperties(debeziumProperties)
+                        .splitSize(2)
+                        .build();
+
+        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+        // enable checkpoint
+        env.enableCheckpointing(3000L);
+        // set the source parallelism to 4
+        env.fromSource(
+                        oracleChangeEventSource,
+                        WatermarkStrategy.noWatermarks(),
+                        "OracleParallelSource")
+                .setParallelism(4)
+                .print()
+                .setParallelism(1);
+        env.execute("Print Oracle Snapshot + RedoLog");
+    }
+}
+```
+
+#### SourceFunction-based DataStream
 
 ```java
 import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;