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Diffstat (limited to 'contrib/array/array_iterator.doc')
| -rw-r--r-- | contrib/array/array_iterator.doc | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/contrib/array/array_iterator.doc b/contrib/array/array_iterator.doc new file mode 100644 index 00000000000..01c1b2195cf --- /dev/null +++ b/contrib/array/array_iterator.doc @@ -0,0 +1,26 @@ +From: Massimo Dal Zotto <dz@cs.unitn.it> +Date: Mon, 6 May 1996 01:03:37 +0200 (MET DST) +Subject: [PG95]: new operators for arrays + +- -----BEGIN PGP SIGNED MESSAGE----- + +Hi, + +I have written an extension to Postgres95 which allows to use qualification +clauses based on the values of single elements of arrays. +For example I can now select rows having some or all element of an array +attribute equal to a given value or matching a regular expression: + +select * from t where t.foo *= 'bar'; +select * from t where t.foo **~ '^ba[rz]'; + +The scheme is quite general, each operator which operates on a base type can +be iterated over the elements of an array. It seem to work well but defining +each new operators requires writing a different C function. Furthermore in +each function there are two hardcoded OIDs which reference a base type and +a procedure. Not very portable. Can anyone suggest a better and more portable +way to do it ? Do you think this could be a useful feature for next release ? +Here is my code, it can be compiled and loaded as a dynamic module without +need to recompile the backend. I have defined only the few operators I needed, +the list can be extended. Feddback is welcome. + |