Re: [sqlite] How to design this table?

[Ivan Shmakov]

> Simon Slavin writes:
> On 9 Oct 2011, at 3:57am, 张一帆 wrote:

 >> i have some data like "a and b or c ...",there will be a word 'and'
 >> or 'or' which means the Logical relations between each item.

 > If you have "a and b or c" does that mean

 > (a and b) or cOR
 > a and (b or c)?

 > How does your software know ?

The boolean AND and OR operations are often compared to the
usual arithmetics' × and +.  Therefore, a AND b OR c is akin to
a × b + c, and the precedence rules (borrowed from arithmetics)
will make that (a × b) + c.

And SQLite, among many others, behaves just like that:

$ sqlite3 :memory: 'SELECT 0 AND  1 OR 1' 
1
$ sqlite3 :memory: 'SELECT 0 AND (1 OR 1)' 
0
$ 

I guess that it just follows the standard.

-- 
FSF associate member #7257

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Re: [sqlite] How to design this table?

[Igor Tandetnik]

张一帆  wrote:
> i have some data like "a and b or c ...",there will be a word 'and' or
> 'or' which means the Logical relations between each item.So how to design a
> table to store the data in best way?

Best way to achieve which goals? What operations do you need to perform on said 
data?
-- 
Igor Tandetnik

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Re: [sqlite] How to design this table?

[zyf01234]

> > i have some data like "a and b or c ...",there will be a word 'and' or
> > 'or' which means the Logical relations between each item.

> If you have "a and b or c" does that mean

> (a and b) or c OR
> a and (b or c) ?

> How does your software know ?

> Simon.


just a and b or c...,like this.thank you! i am also think about the solution of 
this case.Do you have any ideas?
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Re: [sqlite] How to design this table?

[Simon Slavin]

On 9 Oct 2011, at 3:57am, 张一帆 wrote:

> i have some data like "a and b or c ...",there will be a word 'and' or
> 'or' which means the Logical relations between each item.

If you have "a and b or c" does that mean

(a and b) or cOR
a and (b or c)?

How does your software know ?

Simon.
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