On Sun, 2002-12-29 at 22:09, li li wrote:
> As we can see all tuples of a child table when scanning parent table,
> I'm confused about if that means there are two copies that are stored on
> disk, one is for child table, and the other for parent table? If so,
> I have to reconsider the size of my database.
When you select from the parent table, all rows in its children are also
selected unless you use the keyword ONLY.
SELECT * FROM parent;
will show all rows of parent and children. But
SELECT * FROM ONLY parent;
will show just the rows in the parent table.
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight, UK http://www.lfix.co.uk/oliver
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"Ye have heard that it hath been said, Thou shalt love
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In response to
pgsql-performance by date
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