DB driver feature matrix:

Symbols:
  "x" - implemented, but without tests
  "t" - implemented, but one or more tests fail
  "T" - implemented, passing all tests
  "e" - emulated, without tests
  "E" - emulated, passing all tests
  "n" - returns "not capable"
  "-" - no implementation of this feature

FEATURE         ibase   msql    mssql   mysql   oci8    odbc    pgsql   sybase
simpleQuery       x       x       x       T       x       x       T       x
numCols           x       x       x       T       x       x       T       x
numRows           n       x       x       T       n       n       T       n
errorNative       n       n       n       T       x       x       T       n
prepare/execute   x       e       e       E       x       e       E       e
sequences         n       n       n       E       n       n       T       n
affectedRows      n       n       n       T       x       n       T       n
fetch modes       x       x       x       T       x       x       T       x
transactions      x       n       n       n       x       x       x       n
auto-commit       x       n       n       n       x       x       x       n
error mapping     -       -       -       T       -       x       E       -
