Examples

These examples are for illustration only and are not taken from an actual system.

Pre-query rule examples

The following code shows an example which checks variable count and maximum table size. The example illustrates how the allowed variable count might vary with geographic level of the query.

querytest main()
  fail if not checkGeoFirst()
  fail if not checkMaxVars(4,6)
  fail if not checkMaxCells(10*1000*1000)
end

querytest checkGeoFirst()
  for v in query.vars
    if (v.index > 0) && ("SMALL_GEO" sourceof v.name)
      fail "GEO_NOT_FIRST"
    end
  end
end

querytest checkMaxVars(maxSmall, max)
  if (query.vars[0].name sourceof "SMALL_GEO") &&
      ((len query.vars) > (maxSmall + 1))
    fail "MAX_VARS_SMALL_GEO"
  end
  if "SMALL_GEO" sourceof query.vars[0].name
    if (len query.vars) > (max + 1)  // any geographic query
      fail "MAX_VARS_GEO"
    end
  else  // not a geographic query
    if (len query.vars) > max
      fail "MAX_VARS_NON_GEO"
    end
  end
end

querytest checkMaxCells(max)
  var numCells = 1
  for v in query.vars
    numCells *= (len v.cats)
  end
  fail "TABLE_TOO_BIG"
end

Post-query rule examples

The following code shows a sample of possible rules governing the output tables. Note that we use “per-mille” (fraction of a thousand) rather than “percent” for extra resolution using integer arithmetic.

tabletest main()
  // All univariate queries are allowed without checking the other rules
  pass if Univariate()
  fail if not MaxPermilleZeros(718)
  fail if not MaxPermilleOnes(281)
  fail if not MaxMarginalTotalPermille(828)
  fail if not MaxPermilleDisclosiveCells(45, 2, 5)
end

// Create a table to test without "Not Applicable" categories.
// This is computed on demand.

tabledef tableWithoutNA
for c in table.cats
  fail if c.code eq "N/A"
end

// Compute some counts from our derived table.
// This code is executed when any of these properties is first accessed.

tableprops sumCounts, nZeros, nPopulated, nOnes, nRealOnes
for cell in tableNoM9.cells
  sumCounts += cell.count
  if cell.count == 0
    nZeros += 1
  else
    nPopulated += 1
    if cell.count == 1
      nOnes += 1
      if cell.key != 0
        nRealOnes += 1
      end
    end
  end
end

// Test if only one non-geographic variable

tabletest Univariate()
  pass if (len table.vars) == 1
  pass if ("SMALL_GEO" sourceof table.vars[0].name) && ((len table.vars) == 2)
  fail
end

// Test that the maximum marginal total must be at most
// the specified fraction "per-thousand" of the table total.

tabletest MaxMarginalTotalPermille(maxPerMilleTotal)
  var maxTotal = (maxPerMilleTotal * tableWithoutNA.sumCounts) / 1000
  for c in tableWithoutNA.cats
    fail if c.total > maxTotal
  end
end

// Test that no more than the specified fraction "per-thousand"
// of internal cells can be zero.

tabletest MaxPermilleZeros(perMilleCells)
  fail if (tableWithoutNA.nZeros * 1000) > ((len tableWithoutNA.cells) * perMilleCells)
end

// Test that no more than the specified fraction "per-thousand"
// of populated cells can be one.

tabletest MaxPermilleOnes(perMilleCells)
  fail if (tableWithoutNA.nOnes * 1000) > (tableWithoutNA.nPopulated * perMilleCells)
end

// Test that the table contains not more than the fraction "per-thousand"
// of disclosive cells with parameters for category and count thresholds.

tabletest MaxPermilleDisclosiveCells(perMilleCells, minCats, maxCount)
  var threshold = (perMilleCells * (len tableWithoutNA.cells)) / 1000
  var count = 0
  for margin in tableWithoutNA.margins
    continue if (len tableWithoutNA.vars[margin.index].cats) < minCats
    for cell in margin.cells
      continue if cell.disclosiveCellIndex < 0
      continue if cell.count > maxCount
      continue if marked tableWithoutNA.cells[cell.disclosiveCellIndex]
      mark tableWithoutNA.cells[cell.disclosiveCellIndex]
      count += 1
      fail if count > threshold
    end
  end
end