Subset a chMDB object according to row position in one table and return a memoMDB
Source:R/chMDB.R
      slice.chMDB.RdArguments
- .data
- a chMDB object 
- ...
- a single argument. The name of this argument should be a table name of x and the value of this argument should be vector of integers corresponding to row indexes. 
- by
- the size of the batch: number of records to slice together (default: 10^5) 
- .preserve
- not used 
Value
a memoMDB object