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[题库] Oracle OCP题库解析(8)

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发表于 2012-2-2 17:20:04 | 显示全部楼层 |阅读模式
本帖最后由 ITAA-OCM 于 2012-2-2 17:21 编辑

View the Exhibit.
Which statement regarding the dept and emp tables is true?
A) When you delete a row from the emp table, you would receive a constraint violation error.
B) When you delete a row from the dept table, you would receive a constraint violation error.
C) When you delete a row from the emp table, automatically the corresponding rows are deleted from the dept table.
D) When you delete a row from the dept table, automatically the corresponding rows are deleted from the emp table.
E) When you delete a row from the dept table, automatically the corresponding rows are updated with null values in the emp table.
F) When you delete a row from the emp table, automatically the corresponding rows are updated with null values in the dept table.
Answer: D
ON DELETE CASCADE当主键内容被删除,他所对应的外键内容将自动删除。

发表于 2013-1-22 17:44:10 | 显示全部楼层
沙发 2013-1-22 17:44:10 回复 收起回复
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发表于 2014-10-21 12:48:49 | 显示全部楼层
学学一下,加油
地板 2014-10-21 12:48:49 回复 收起回复
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