hi i know that shrinking data base increase fragmentation , so logically shrinking data files would two result in fragmentation but does shrinking log file increases fragmentation. i hope answer is NO.
Index fragmentation, no. However, lots of shrink/grow/shrink/grow will cause log fragmentation. You shouldn't be regularly shrinking your logs. Once off, yes. Regular, no.
Please read through this - Managing Transaction Logs
Second question is rebuilding an index reduces fragmentation but it increase size of database.I have seen increase in size of log file but does data file size to increases .
Yes it can. If there's not enough space in the database for the new index, the data file will grow.
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