NULL values in BIT(1) columns are returned as TRUE

[dirkschumacher]

It seems that with version 1.1.0 BIT(1) columns that have NULL values return TRUE instead of NA. This might be a bug introduced in #192.

library(RMariaDB)
con <- dbConnect(MariaDB(), dbname = "test")
dbWriteTable(con, "test", data.frame(a = c(NA_integer_, 0:1)), field.types = c(a = "BIT(1)"), overwrite = TRUE)
dbReadTable(con, "test")$a
#> [1] TRUE FALSE TRUE

The dbWriteTable call creates a table with the below CREATE statement. The table on the server does contain the values NULL, 0 and 1 on my MySQL instance (version 8).

CREATE TABLE `test` (
  `a` BIT(1) NULL DEFAULT NULL
)

The problem might be here, where NA_INTEGER is mapped to 1 it seems.

RMariaDB/src/MariaRow.cpp

Lines 216 to 218 in 5241355

	case MY_LGL:
	LOGICAL(x)[i] = value_int(j) ? 1 : 0;
	break;

Happy to contribute a fix and thanks for all your work!

[krlmlr]

Good catch, what an evil glitch. I agree with your analysis, happy to review a PR!

[github-actions]

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