Hi Riccardo, Do not think that last strategy will be more efficient, your complexity in last case can be huge, but index request always has logarithmic complexity multiplied by amount of ORs.
On Mon, Feb 17, 2014 at 10:19 AM, Riccardo Tasso <[email protected]>wrote: > Hi all, > I have to represent a domain with OrientDB and I'm thinking about two > ways. The domain is as follows: > > - a very big text is fragmented in Chunks of equal size (let's say 5 > characters for each Chunk) > - Chunk is a class with <begin, end, text> attributes > > For example, the text: "Hello World!" becomes: > > 1. 0, 5, "Hello" > 2. 5, 10, " Worl" > 3. 10, 12, "d!" > > The user can ask for an arbitrary span of text, for example: getText(6, > 11) should return "World". > > Currently I collect all the interesting chunks with the following query: > SELECT begin, end, text > FROM Chunk > WHERE > (begin <= 6 AND end >= 6) OR // the first interesting chunk > (begin >= 6 AND end <= 11) OR // all the other chunks > (begin <= 11 AND end >= 11) // the last interesting chunk > ORDER BY begin > Obviously such a query can be optimized with an index over begin, end > fields. > > I was thinking about another option, which is to link each Chunk with its > follower, for example: 1. -- next --> 2. -- next --> 3. > In this case the previous query could be implemented as a traversal: > TRAVERSE all() FROM (SELECT FROM Chunk WHERE begin <= 6 AND end > 6)WHILE > end <= 11 > > Considering that each Chunk has only one follower, do you think this > strategy would be more efficient? > > Cheers, > Riccardo > > -- > > --- > You received this message because you are subscribed to the Google Groups > "OrientDB" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- Best regards, Andrey Lomakin. Orient Technologies the Company behind OrientDB -- --- You received this message because you are subscribed to the Google Groups "OrientDB" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
