@Override
  public PlanNodeType getType() {
    return PlanNodeType.ALTER_LOGICAL_VIEW;
  }
A map from target path to source expression. Yht target path is the name of this logical view,
and the source expression is the data source of this view.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/node/metadata/write/view/AlterLogicalViewNode.java