Dominique Devienne, on Thursday, May 23, 2019 07:02 AM, wrote...
>On Thu, May 23, 2019 at 12:37 PM Simon Slavin <slav...@bigfraud.org> wrote:
>> On 23 May 2019, at 3:55am, Keith Medcalf <kmedc...@dessus.com> wrote:
>> > Technically, COLLATE only works on TEXT. Most people declare their own
>> types as binary blobs and the programmer has to keep track of what is in
>> there and how to work with it.
>>
>> So it would seem that rather than define a function which turns a value of
>> my type into a BLOB, it would be better to create one which turns it into
>> some sort of normalised text form. Then I can create whatever COLLATEs I
>> need to do my specialised sorting and handling.
>>
>> IP addresses are easy: convert to the form aaa.bbb.ccc.ddd where each of
>> the four parts is always three digits long.
>
>
>Sure. But representing it as 001.001.001.001 for 1.1.1.1 is not usual.
>You'd better have a CHECK constraint to enforce your format.
>Otherwise lexical ordering won't work with non-expected (but more natural)
>1.1.1.1.
>While writing a custom collation (the so called "natural ordering") would
>work for either format. --DD
Microsoft ping fails with 010.116.082.097,
9:45:39.71>ping 010.116.082.097
Ping request could not find host 010.116.082.097. Please check the name and try
again.
but, works with the normal unzeroed format,
9:45:55.21>ping 10.116.82.97
Pinging 10.116.82.97 with 32 bytes of data:
Reply from 10.116.82.97: bytes=32 time<1ms TTL=128
Reply from 10.116.82.97: bytes=32 time<1ms TTL=128
Reply from 10.116.82.97: bytes=32 time<1ms TTL=128
Reply from 10.116.82.97: bytes=32 time<1ms TTL=128
Ping statistics for 10.116.82.97:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
I have been working network for a long time, and I have never seen any
application that takes "zeroed left-filled" IP addresses. Just sharing...
Thanks.
josé
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