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                [TOC] # 管理視圖 視圖用來展示表的查詢結果。大部分能使用表的地方,都可以使用視圖。如果經常訪問的數據分布在多個表里時,使用視圖是最好的方法。 ## 創建視圖 您可以使用`CREATE VIEW`語句來創建視圖。 示例:創建視圖 stock\_item。該視圖內容取自 stock 和 item 兩張表,兩張表做表連接即可得到該視圖。 ~~~ obclient> CREATE VIEW stock_item AS SELECT /*+ leading(s) use_merge(i) */ i_price, i_name, i_data, s_i_id, s_w_id, s_order_cnt, s_ytd, s_remote_cnt, s_quantity, s_data, s_dist_01, s_dist_02, s_dist_03, s_dist_04, s_dist_05, s_dist_06, s_dist_07, s_dist_08, s_dist_09, s_dist_10 FROM stok s, item i WHERE s.s_i_id = i.i_id; Query OK, 0 rows affected (0.01 sec) ~~~ ## 修改視圖 您可以使用`CREATE OR REPLACE VIEW`語句來對視圖進行修改。 示例:修改視圖 stock\_item。 ~~~ obclient> CREATE OR REPLACE VIEW stock_item AS SELECT /*+ leading(s) use_merge(i) */ i_price, i_name, i_data, s_i_id, s_w_id, s_order_cnt, s_ytd, s_remote_cnt, s_quantity, s_data, s_dist_01, s_dist_02, s_dist_03, s_dist_04, s_dist_05, s_dist_06, s_dist_07, s_dist_08, s_dist_09, s_dist_10 FROM stok s, item i WHERE s.s_i_id = i.i_id; Query OK, 0 rows affected (0.02 sec) ~~~ ## 刪除視圖 您可以使用`DROP VIEW`語句刪除一個或多個視圖,刪除視圖并不會刪除視圖引用的表。 如果當前視圖被其他視圖所引用,則視圖刪除后將會導致依賴當前視圖的其他視圖的查詢失敗。 刪除視圖時,需確保當前用戶具備該視圖的 DROP 權限。 示例:刪除視圖 V1。 ~~~ obclient> DROP VIEW V1; ~~~
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