fix

Author: zml1206

flink-cdc-connect/flink-cdc-pipeline-connectors/flink-cdc-pipeline-connector-oracle/src/test/java/org/apache/flink/cdc/connectors/oracle/source/OraclePipelineITCase.java

@@ -1727,7 +1727,7 @@ private List<Event> executeAlterAndProvideExpected(TableId tableId, Statement st
 
         statement.execute(
                 String.format(
-                        "ALTER TABLE %s.products ADD DESC1 VARCHAR(45) DEFAULT '' NOT NULL",
+                        "ALTER TABLE %s.products ADD DESC1 VARCHAR(45) DEFAULT 'N/A' NOT NULL",
                         "debezium"));
         expected.add(
                 new AddColumnEvent(