CREATE TYPE for case insensitive text and varchar
Hallo.
i just coded a new datatype named "cistring", that can be
used in every function that accepts text or varchar, and has
the great ability to be ordered case insensitive in ORDER BY-
Clauses and Indices. The problem is, that its coded like the
text-type, so it is variable length completly.
I miss the possibility to code something like a userdifined
varchar(n). I don't know how to create an input function,
that accepts the size of the type, or a function, how to declare
such types at all. I think, somethink like a userdefined
numeric(n,m) isn't possible, too, or am I wrong?
Thank you for all replies,
Daniel Migowski
Daniel Migowski <nur-gueltig-bis-2003-12-01@Mig-O.de> writes:
I miss the possibility to code something like a userdifined
varchar(n).
You're out of luck on that. The data types that can have precision
parameters attached to them are hard-wired into the parser.
regards, tom lane
Tom Lane wrote:
Daniel Migowski <nur-gueltig-bis-2003-12-01@Mig-O.de> writes:
I miss the possibility to code something like a userdifined
varchar(n).You're out of luck on that. The data types that can have precision
parameters attached to them are hard-wired into the parser.
Maybe you don't need to invent a whole new data type but the existing
varchar can serve just fine?
The attached script for version 7.3.4 (does not work with 7.4)
demonstrates how to add case insensitive operators *=, *> and so on
including an operator class for btree to the existing varchar.
All one has to do is to use *= instead of = in queries. Indexes, even
unique, based on case insensitive comparision are possible too and well
supported. The only thing I think wouldn't work are IN and NOT IN
constructs.
Jan
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