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27 lines
1.2 KiB
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27 lines
1.2 KiB
Plaintext
From: Massimo Dal Zotto <dz@cs.unitn.it>
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Date: Mon, 6 May 1996 01:03:37 +0200 (MET DST)
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Subject: [PG95]: new operators for arrays
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- -----BEGIN PGP SIGNED MESSAGE-----
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Hi,
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I have written an extension to Postgres95 which allows to use qualification
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clauses based on the values of single elements of arrays.
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For example I can now select rows having some or all element of an array
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attribute equal to a given value or matching a regular expression:
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select * from t where t.foo *= 'bar';
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select * from t where t.foo **~ '^ba[rz]';
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The scheme is quite general, each operator which operates on a base type can
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be iterated over the elements of an array. It seem to work well but defining
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each new operators requires writing a different C function. Furthermore in
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each function there are two hardcoded OIDs which reference a base type and
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a procedure. Not very portable. Can anyone suggest a better and more portable
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way to do it ? Do you think this could be a useful feature for next release ?
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Here is my code, it can be compiled and loaded as a dynamic module without
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need to recompile the backend. I have defined only the few operators I needed,
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the list can be extended. Feddback is welcome.
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