I’m writing a SQL interface for Oracle and have a question on representing the result sets.
My approach is to create tables that look like this:
resultMeta = {
columnA = {pos
= 1, type = “varchar2”,
length = 11, precision = nil},
columnB = {pos
= 2, type = “number”
, length = 5, precision = 2},
columnC = {pos
= 3, type = “varchar2”,
length = 40, precision = nil},
columnD = {pos = 4, type
= “date” , length = nil, precision = nil},
}
resultSet[1] = {[[e]],
0, nil, [[2010/12/25 00:00:00 UTC]]}
result = { meta = resultMeta, set = resultSet, rowCount = #set }
That makes it tough for the developers to use the data. They have to use
row = result.set[rowNumber]
val = row[result.meta[columnB].pos]
I’d like something friendlier like
result[rowNumber][columnB]
I can’t figure out how write that in lua. I made the result set look like
resultSet[1] = {
columnA = [[e]],
columnB = 0,
columnC = nil,
columnD = [[2010/12/25 00:00:00 UTC]]
}
I’m stumped with the [x][y] reference. Is this harder than it seems because I’m not thinking this through using a Lua idiom?
I know that it’s too early to concentrate on optimizing, but I am concerned that looking up via a string key will be slower than via a numeric key. Since this will be operating in a loop over large data sets (daily runs with a set of a million rows), little
improvements may help.
