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工作学习 / IT技术讨论 / Can Table be Inheretence? details in contents.For example:
The first table: (id char(5), name varchar2(20))
The second table: (id char(5), name varchar2(20), age int)
The first table: (id char(5), name varchar2(20), age int, pc char(6))
......
I may need such tables more than 20.
if can inheret, I'll not care too much about the table name or type. Otherwise, if I should add one column into every table, that should be a hard work for me.
tks.
-howru(How are you?);
2001-10-5
{416}
(#217493@0)
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There is no inheretence like what you said in Oracle. why you use the tables like that. If you follow the ERD you never get the tables like these.
-onewayticket(onewayticket);
2001-10-5
(#217742@0)
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Dear oneway, that is the key. Such problem is just occured in ERD. I should design a tree structure database like catalogue-catalogue-catalogue-item. and ...
-howru(How are you?);
2001-10-6
{616}
(#217943@0)
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Try this SQLWhy not try the following SQL query from ONE table?
SELECT LPAD(\
-onewayticket(onewayticket);
2001-10-6
{70}
(#217984@0)
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Try this hierarchical query.
-onewayticket(onewayticket);
2001-10-6
{566}
(#217993@0)
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Tree structure should not be presented by all the level columns, but only by the column like parent_id. The poor design will bring you a lot trouble later.
-cyt(cyt);
2001-10-7
(#218874@0)