OdbcResult: Ability to explicitely describe parameters

NAMESPACE

@@ -4,6 +4,7 @@ S3method(odbcListColumns,OdbcConnection)
 S3method(odbcListObjectTypes,default)
 S3method(odbcListObjects,OdbcConnection)
 S3method(odbcPreviewObject,OdbcConnection)
+export(ODBC_TYPE)
 export(databricks)
 export(isTempTable)
 export(odbc)

R/RcppExports.R

@@ -77,6 +77,24 @@ bigint_mappings <- function() {
     .Call(`_odbc_bigint_mappings`)
 }
 
+#' Access the definition of the named SQL Data Type.
+#'
+#' @description Helper method returning the integer of the
+#' [SQL Data Type](https://learn.microsoft.com/en-us/sql/odbc/reference/appendixes/sql-data-types?view=sql-server-ver16)
+#' named in the argument.
+#'
+#' @seealso <https://github.com/microsoft/ODBC-Specification/blob/master/Windows/inc/sql.h>
+#' @rdname odbcDataType.
+#' @examples
+#' \dontrun{
+#' library(odbc)
+#' ODBC_TYPE("LONGVARCHAR")
+#' }
+#' @export
+ODBC_TYPE <- function(type) {
+    .Call(`_odbc_ODBC_TYPE`, type)
+}
+
 result_release <- function(r) {
     invisible(.Call(`_odbc_result_release`, r))
 }

R/dbi-result.R

@@ -126,17 +126,54 @@ setMethod("dbGetRowsAffected", "OdbcResult",
   }
 )
 
+#' @param param_description A data.frame with per-parameter attribute
+#' overrides.  Argument is optional; if used it must have columns:
+#' * param_index Index of parameter in query ( beginning with 1 ).
+#' * data_type Integer corresponding to the parameter SQL Data Type.
+#'   See \code{\link{ODBC_TYPE}}.
+#' * column_size Size of parameter.
+#' * decimal_digits Either precision or the scale of the parameter
+#'   depending on type.
+#'
+#' For more information see the [ODBC SQLBindParam documentation](https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlbindparameter-function?view=sql-server-ver16)
+#'
+#' @examples
+#' \dontrun{
+#' library(odbc)
+#' # Writing UNICODE into a VARCHAR
+#' # column with SQL server
+#' DBI::dbRemoveTable(conn, "#tmp")
+#' dbExecute(conn, "CREATE TABLE #tmp (col1 VARCHAR(50) COLLATE Latin1_General_100_CI_AI_SC_UTF8);")
+#' res <- dbSendQuery(conn, "INSERT INTO #tmp SELECT ? COLLATE Latin1_General_100_CI_AI_SC_UTF8")
+#' description <- data.frame(param_index = 1, data_type = ODBC_TYPE("WVARCHAR"),
+#'   column_size = 5, decimal_digits = NA_integer_)
+#' dbBind(res, params = list("\u2915"), param_description = description)
+#' dbClearResult(res)
+#' DBI::dbReadTable(conn, "#tmp")
+#' }
 #' @rdname OdbcResult
 #' @inheritParams DBI::dbBind
 #' @inheritParams DBI-tables
 #' @export
 setMethod("dbBind", "OdbcResult",
-  function(res, params, ..., batch_rows = getOption("odbc.batch_rows", NA)) {
+  function(res, params, ...,
+           param_description = data.frame(),
+           batch_rows = getOption("odbc.batch_rows", NA)) {
     params <- as.list(params)
     if (length(params) == 0) {
       return(invisible(res))
     }
 
+    if (nrow(param_description)) {
+      if (!all(c("param_index", "data_type", "column_size", "decimal_digits")
+        %in% colnames(param_description))) {
+        cli::cli_abort(
+          "param_description data.frame does not have necessary columns."
+        )
+      }
+      result_describe_parameters(res@ptr, param_description)
+    }
+
     if (is.na(batch_rows)) {
       batch_rows <- length(params[[1]])
     }

src/Makevars.in

@@ -4,7 +4,7 @@ PKG_CPPFLAGS=@PKG_CFLAGS@
 PKG_CXXFLAGS=-Icctz/include -Inanodbc -I. -DBUILD_REAL_64_BIT_MODE -DNANODBC_ODBC_VERSION=SQL_OV_ODBC3 $(CXXPICFLAGS)
 PKG_LIBS=@PKG_LIBS@ -Lcctz -lcctz
 
-OBJECTS = odbc_result.o connection.o nanodbc.o result.o odbc_connection.o RcppExports.o Iconv.o utils.o
+OBJECTS = odbc_types.o odbc_result.o connection.o nanodbc.o result.o odbc_connection.o RcppExports.o Iconv.o utils.o
 
 all: $(SHLIB)
 

src/Makevars.win

@@ -1,7 +1,7 @@
 PKG_CXXFLAGS=-I. -Icctz/include -Inanodbc
 PKG_LIBS=-lodbc32 -Lcctz -lcctz
 
-OBJECTS = odbc_result.o connection.o nanodbc.o result.o odbc_connection.o RcppExports.o Iconv.o utils.o
+OBJECTS = odbc_types.o odbc_result.o connection.o nanodbc.o result.o odbc_connection.o RcppExports.o Iconv.o utils.o
 
 all: $(SHLIB)
 

src/RcppExports.cpp

@@ -228,6 +228,17 @@ BEGIN_RCPP
     return rcpp_result_gen;
 END_RCPP
 }
+// ODBC_TYPE
+int ODBC_TYPE(const std::string& type);
+RcppExport SEXP _odbc_ODBC_TYPE(SEXP typeSEXP) {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    Rcpp::traits::input_parameter< const std::string& >::type type(typeSEXP);
+    rcpp_result_gen = Rcpp::wrap(ODBC_TYPE(type));
+    return rcpp_result_gen;
+END_RCPP
+}
 // result_release
 void result_release(result_ptr r);
 RcppExport SEXP _odbc_result_release(SEXP rSEXP) {
@@ -384,6 +395,7 @@ static const R_CallMethodDef CallEntries[] = {
     {"_odbc_transactionLevels", (DL_FUNC) &_odbc_transactionLevels, 0},
     {"_odbc_set_transaction_isolation", (DL_FUNC) &_odbc_set_transaction_isolation, 2},
     {"_odbc_bigint_mappings", (DL_FUNC) &_odbc_bigint_mappings, 0},
+    {"_odbc_ODBC_TYPE", (DL_FUNC) &_odbc_ODBC_TYPE, 1},
     {"_odbc_result_release", (DL_FUNC) &_odbc_result_release, 1},
     {"_odbc_result_active", (DL_FUNC) &_odbc_result_active, 1},
     {"_odbc_result_completed", (DL_FUNC) &_odbc_result_completed, 1},

src/odbc_types.cpp

@@ -0,0 +1,67 @@
+#include <unordered_map>
+#include <string>
+#include <sql.h>
+#include <sqlext.h>
+#include <sqlucode.h>
+#include "utils.h"
+#define INSTANTIATE_SQL_DATA_TYPE(TYPE) _the_map[#TYPE] = SQL_##TYPE;
+
+using namespace odbc;
+const std::unordered_map< std::string, int >& generateOdbcTypes() {
+  static std::unordered_map< std::string, int > _the_map;
+  INSTANTIATE_SQL_DATA_TYPE(CHAR);
+  INSTANTIATE_SQL_DATA_TYPE(VARCHAR)
+  INSTANTIATE_SQL_DATA_TYPE(LONGVARCHAR);
+
+  INSTANTIATE_SQL_DATA_TYPE(WCHAR);
+  INSTANTIATE_SQL_DATA_TYPE(WVARCHAR);
+  INSTANTIATE_SQL_DATA_TYPE(WLONGVARCHAR);
+
+  INSTANTIATE_SQL_DATA_TYPE(DECIMAL);
+  INSTANTIATE_SQL_DATA_TYPE(NUMERIC);
+  INSTANTIATE_SQL_DATA_TYPE(SMALLINT);
+  INSTANTIATE_SQL_DATA_TYPE(INTEGER);
+  INSTANTIATE_SQL_DATA_TYPE(REAL);
+  INSTANTIATE_SQL_DATA_TYPE(FLOAT);
+  INSTANTIATE_SQL_DATA_TYPE(DOUBLE);
+
+  INSTANTIATE_SQL_DATA_TYPE(BIT);
+  INSTANTIATE_SQL_DATA_TYPE(TINYINT);
+  INSTANTIATE_SQL_DATA_TYPE(BIGINT);
+
+  INSTANTIATE_SQL_DATA_TYPE(BINARY);
+  INSTANTIATE_SQL_DATA_TYPE(VARBINARY);
+  INSTANTIATE_SQL_DATA_TYPE(LONGVARBINARY);
+
+  INSTANTIATE_SQL_DATA_TYPE(TYPE_DATE);
+  INSTANTIATE_SQL_DATA_TYPE(TYPE_TIME);
+  INSTANTIATE_SQL_DATA_TYPE(TYPE_TIMESTAMP);
+  return _the_map;
+}
+
+//' Access the definition of the named SQL Data Type.
+//'
+//' @description Helper method returning the integer of the
+//' [SQL Data Type](https://learn.microsoft.com/en-us/sql/odbc/reference/appendixes/sql-data-types?view=sql-server-ver16)
+//' named in the argument.
+//'
+//' @seealso <https://github.com/microsoft/ODBC-Specification/blob/master/Windows/inc/sql.h>
+//' @rdname odbcDataType.
+//' @examples
+//' \dontrun{
+//' library(odbc)
+//' ODBC_TYPE("LONGVARCHAR")
+//' }
+//' @export
+// [[Rcpp::export]]
+int ODBC_TYPE(const std::string& type) {
+  static const std::unordered_map< std::string, int >& map =
+    generateOdbcTypes();
+  auto itr = map.find(type);
+  if (itr != map.end())
+  {
+    return (int)itr->second;
+  }
+  utils::raise_error("Could not map input string to ODBC type");
+  return 0;
+}