[Haskell-cafe] Purely Functional Data Structures
ok at cs.otago.ac.nz
Sun Mar 8 22:07:17 EDT 2009
On 8 Mar 2009, at 12:13 pm, G?uenther Schmidt wrote:
> Hi Don,
> damn, that was quick!
> And thx, I'll look into that. The reading it in wasn't much of a
> problem, I had been able to use MS-ODBC for that, there's a driver
> for ODBC files. The problem is more the type of data structure I'd
> be reading it into. In SQL I would have the data indexed by several
> different columns, if I use maps I'd only have one key, so if I need
> to lookup data in the map by a value that is not the key the lookups
> will become quite expensive.
> Any suggestions, what do you do in these cases?
Who said you could only have one map?
You can have as many as you want:
primary :: Map Key1 (Maybe Whole_Record)
secondary :: Map Key2 [Whole_Record]
Adding the same record to both maps won't copy the record.
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