Merged PR 5320: Enhance Data Handling and Precision in DDBC Bindings

This PR introduces several improvements and fixes to the DDBC bindings, focusing on data handling, precision, and proper rounding for various SQL data types. The key changes include:

1. **Handling SQL_FLOAT and SQL_REAL with Proper Rounding:**

2. **Handling SQL_FLOAT  and SQL_DOUBLE:**
   - Ensured that `SQL_DOUBLE` values are fetched and appended to the row with the correct precision.

**Testing:**
- Updated the test script `testing_ddbc_bindings.py` to include test cases for the newly handled data types and conversions.
- Verified that the data is fetched and converted correctly for various SQL data types, including numeric, time, and binary types.

**Impact:**
- These changes enhance the robustness and accuracy of data handling in the DDBC bindings, ensuring that various SQL data types are correctly fetched, converted, and appended to the result rows.
- The improvements also make the codebase more maintainable and easier to understand.

**Reviewer Notes:**
- Please review the changes to the handling of `SQL_FLOAT`, `SQL_REAL`, and `SQL_DOUBLE` with proper rounding.

Related work items: #33831

Author: Ramudaykumar

mssql_python/pybind/ddbc_bindings.cpp

@@ -105,7 +105,7 @@ struct ColumnBuffers {
     std::vector<std::vector<SQLWCHAR>> wcharBuffers;
     std::vector<std::vector<SQLINTEGER>> intBuffers;
     std::vector<std::vector<SQLSMALLINT>> smallIntBuffers;
-    std::vector<std::vector<SQLFLOAT>> floatBuffers;
+    std::vector<std::vector<SQLREAL>> realBuffers;
     std::vector<std::vector<SQLDOUBLE>> doubleBuffers;
     std::vector<std::vector<SQL_NUMERIC_STRUCT>> numericBuffers;
     std::vector<std::vector<SQL_TIMESTAMP_STRUCT>> timestampBuffers;
@@ -120,7 +120,7 @@ struct ColumnBuffers {
           wcharBuffers(numCols),
           intBuffers(numCols),
           smallIntBuffers(numCols),
-          floatBuffers(numCols),
+          realBuffers(numCols),
           doubleBuffers(numCols),
           numericBuffers(numCols),
           timestampBuffers(numCols),
@@ -906,12 +906,11 @@ SQLRETURN SQLGetData_wrap(intptr_t StatementHandle, SQLUSMALLINT colCount, py::l
                 }
                 break;
             }
-            case SQL_FLOAT:
             case SQL_REAL: {
-                SQLREAL floatValue;
-                ret = SQLGetData_ptr(hStmt, i, SQL_C_FLOAT, &floatValue, 0, NULL);
+                SQLREAL realValue;
+                ret = SQLGetData_ptr(hStmt, i, SQL_REAL, &realValue, 0, NULL);
                 if (SQL_SUCCEEDED(ret)) {
-                    row.append(static_cast<float>(floatValue));
+                    row.append(realValue);
                 } else {
                     row.append(py::none());
                 }
@@ -933,11 +932,12 @@ SQLRETURN SQLGetData_wrap(intptr_t StatementHandle, SQLUSMALLINT colCount, py::l
                 }
                 break;
             }
-            case SQL_DOUBLE: {
+            case SQL_DOUBLE:
+            case SQL_FLOAT: {
                 SQLDOUBLE doubleValue;
                 ret = SQLGetData_ptr(hStmt, i, SQL_C_DOUBLE, &doubleValue, 0, NULL);
                 if (SQL_SUCCEEDED(ret)) {
-                    row.append(static_cast<double>(doubleValue));
+                    row.append(doubleValue);
                 } else {
                     row.append(py::none());
                 }
@@ -1154,9 +1154,8 @@ SQLRETURN SQLBindColums(SQLHSTMT hStmt, ColumnBuffers& buffers, py::list& column
                                      sizeof(SQLCHAR), buffers.indicators[col - 1].data());
                 break;
             case SQL_REAL:
-            case SQL_FLOAT:
-                buffers.floatBuffers[col - 1].resize(fetchSize);
-                ret = SQLBindCol_ptr(hStmt, col, SQL_C_FLOAT, buffers.floatBuffers[col - 1].data(),
+                buffers.realBuffers[col - 1].resize(fetchSize);
+                ret = SQLBindCol_ptr(hStmt, col, SQL_REAL, buffers.realBuffers[col - 1].data(),
                                      sizeof(SQLREAL), buffers.indicators[col - 1].data());
                 break;
             case SQL_DECIMAL:
@@ -1167,6 +1166,7 @@ SQLRETURN SQLBindColums(SQLHSTMT hStmt, ColumnBuffers& buffers, py::list& column
                     sizeof(SQL_NUMERIC_STRUCT), buffers.indicators[col - 1].data());
                 break;
             case SQL_DOUBLE:
+            case SQL_FLOAT:
                 buffers.doubleBuffers[col - 1].resize(fetchSize);
                 ret =
                     SQLBindCol_ptr(hStmt, col, SQL_C_DOUBLE, buffers.doubleBuffers[col - 1].data(),
@@ -1305,8 +1305,7 @@ SQLRETURN FetchBatchData(SQLHSTMT hStmt, ColumnBuffers& buffers, py::list& colum
                         row.append(buffers.charBuffers[col - 1][i]);
                         break;
                     case SQL_REAL:
-                    case SQL_FLOAT:
-                        row.append(static_cast<float>(buffers.floatBuffers[col - 1][i]));
+                        row.append(buffers.realBuffers[col - 1][i]);
                         break;
                     case SQL_DECIMAL:
                     case SQL_NUMERIC:
@@ -1320,7 +1319,8 @@ SQLRETURN FetchBatchData(SQLHSTMT hStmt, ColumnBuffers& buffers, py::list& colum
                                 .to_double());
                         break;
                     case SQL_DOUBLE:
-                        row.append(static_cast<double>(buffers.doubleBuffers[col - 1][i]));
+                    case SQL_FLOAT:
+                        row.append(buffers.doubleBuffers[col - 1][i]);
                         break;
                     case SQL_TIMESTAMP:
                     case SQL_TYPE_TIMESTAMP: