数据仓库服务 GaussDB(DWS)-视图迁移:REPLACE VIEW

时间：2025-02-12 15:05:07

REPLACE VIEW

在Teradata中，REPLACE VIEW语句用于创建新视图，或重建现有视图。DSC将其迁移为DWS中兼容的CREATE OR REPLACE VIEW语句中。

输入：REPLACE VIEW

  
       REPLACE VIEW DP_STEDW.MY_PA RAM  AS SELECT          RUNDATE     FROM          DP_STEDW.DATE_TBL     WHERE          dummy = 1;

输出：

  
       CREATEOR REPLACE VIEW DP_STEDW.MY_PARAM AS (     SELECT               RUNDATE          FROM               DP_STEDW.DATE_TBL          WHERE               dummy = 1);

输入：REPLACE RECURSIVE VIEW

  
       Replace RECURSIVE VIEW reachable_from (emp_id,emp_name,DEPTH) AS (SELECT root.emp_id,root.emp_name,0 AS DEPTHFROM emp AS rootWHERE root.mgr_id IS NULL);

输出：

  
       CREATE OR REPLACE VIEW reachable_from AS (WITH RECURSIVE reachable_from (emp_id,emp_name,DEPTH) AS (SELECT root.emp_id,root.emp_name,0 AS DEPTHFROM emp AS rootWHERE root.mgr_id IS NULL) SELECT * FROM reachable_from);