Re: String-with-number sort and insert order preservation

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Hi Šabo,

I don't have a pure Cayenne answer, but in case you can add an extra field to your table, then you can write a simple program to convert your IP addresses to numbers and save the numbers to the newly added field. Here is a simple Java method I am using to convert IPV4s to a long:

    public static long ipAddressToLong(String ipAddress) {
        String[] ipAddressArray = ipAddress.split("\\.");
        long num = 0;

        for (int i = 0; i < ipAddressArray.length; i++) {
            int power = 3 - i;
            num += ((Integer.parseInt(ipAddressArray[i]) % 256 * Math.pow(256, power)));
        }
        return num;
    }

After this simple data transformation it will be very easy to sort your table.

I hope it helps.

V/r
-florin

On 02-Feb-10, at 19:45 , Marek Šabo wrote:

> Hi all,
>
> I would like to ask you two questions:
>
> 1) Is there any way to sort varchar fields which happen to numbers, more
> precisely ipv4s?
> query.addOrdering(Ip4Address.IP_ADDRESS_PROPERTY, SortOrder.ASCENDING);
> This of course sets the hundreds as first in line, any tips on some
> custom sorting?
>
> 2) I was filling ip table with available ranges like this:
>
> ObjectContext oc = DataContext.getThreadObjectContext();
>
> for (int i = 33; i < 255; i++) {
>
> Ip4Address ip = oc.newObject(Ip4Address.class);
>
> ip.setIpAddress("XX.XX.XX." + i);
>
> ip.setUsed(Boolean.FALSE);
>
> ip.setNat(Boolean.FALSE);
>
> }
>
> but cayenne inserted rows like this (probably hashed order for
> optimization):
>
> INFO - QueryLogger - [bind: 1->ipAddress:'XX.XX.XX.97', 2->nat:'false', 3->used:'false']
>
> INFO - QueryLogger - Generated PK: Ip4Address.id = 1
>
> INFO - QueryLogger - === updated 1 row.
>
> INFO - QueryLogger - [bind: 1->ipAddress:'XX.XX.XX.71', 2->nat:'false', 3->used:'false']
>
> INFO - QueryLogger - Generated PK: Ip4Address.id = 2
>
> INFO - QueryLogger - === updated 1 row.
>
>
> Is there any way how to override this mechanism in order to preserve
> order of inserted rows?
>
> TIA,
>
> --
> Marek Šabo
>

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