public void setPreAction(String preAction) {
        this.preAction = preAction;
    }
<p>
The SQL used before a MERGE or APPEND with upsert is run.
</p>

@param preAction
       The SQL used before a MERGE or APPEND with upsert is run.
aws-java-sdk-glue/src/main/java/com/amazonaws/services/glue/model/AmazonRedshiftNodeData.java