GH-47706: [C++][FlightRPC] WIP: ODBC SQLFreeStmt implementation

cpp/src/arrow/flight/sql/odbc/odbc_api.cc

@@ -214,8 +214,45 @@ SQLRETURN SQLFreeHandle(SQLSMALLINT type, SQLHANDLE handle) {
 SQLRETURN SQLFreeStmt(SQLHSTMT handle, SQLUSMALLINT option) {
   ARROW_LOG(DEBUG) << "SQLFreeStmt called with handle: " << handle
                    << ", option: " << option;
-  // GH-47706 TODO: Implement SQLFreeStmt
-  return SQL_INVALID_HANDLE;
+
+  switch (option) {
+    case SQL_CLOSE: {
+      using ODBC::ODBCStatement;
+
+      return ODBCStatement::ExecuteWithDiagnostics(handle, SQL_ERROR, [=]() {
+        ODBCStatement* statement = reinterpret_cast<ODBCStatement*>(handle);
+
+        // Close cursor with suppressErrors set to true
+        statement->CloseCursor(true);
+
+        return SQL_SUCCESS;
+      });
+    }
+
+    case SQL_DROP: {
+      return SQLFreeHandle(SQL_HANDLE_STMT, handle);
+    }
+
+    case SQL_UNBIND: {
+      // GH-47716 TODO: Add tests for SQLBindCol unbinding
+      using ODBC::ODBCDescriptor;
+      using ODBC::ODBCStatement;
+      return ODBCStatement::ExecuteWithDiagnostics(handle, SQL_ERROR, [=]() {
+        ODBCStatement* statement = reinterpret_cast<ODBCStatement*>(handle);
+        ODBCDescriptor* ard = statement->GetARD();
+        // Unbind columns
+        ard->SetHeaderField(SQL_DESC_COUNT, (void*)0, 0);
+        return SQL_SUCCESS;
+      });
+    }
+
+    // SQLBindParameter is not supported
+    case SQL_RESET_PARAMS: {
+      return SQL_SUCCESS;
+    }
+  }
+
+  return SQL_ERROR;
 }
 
 inline bool IsValidStringFieldArgs(SQLPOINTER diag_info_ptr, SQLSMALLINT buffer_length,

cpp/src/arrow/flight/sql/odbc/tests/connection_test.cc

@@ -220,4 +220,46 @@ TEST(SQLSetEnvAttr, TestSQLSetEnvAttrNullValuePointer) {
   ASSERT_EQ(SQL_SUCCESS, SQLFreeEnv(env));
 }
 
+TYPED_TEST(ConnectionTest, TestSQLAllocFreeStmt) {
+  SQLHSTMT statement;
+
+  // Allocate a statement using alloc statement
+  ASSERT_EQ(SQL_SUCCESS, SQLAllocStmt(this->conn, &statement));
+
+  SQLWCHAR sql_buffer[kOdbcBufferSize] = L"SELECT 1";
+  ASSERT_EQ(SQL_SUCCESS, SQLExecDirect(statement, sql_buffer, SQL_NTS));
+
+  // Close statement handle
+  ASSERT_EQ(SQL_SUCCESS, SQLFreeStmt(statement, SQL_CLOSE));
+
+  // Free statement handle
+  ASSERT_EQ(SQL_SUCCESS, SQLFreeStmt(statement, SQL_DROP));
+}
+
+TYPED_TEST(ConnectionHandleTest, TestCloseConnectionWithOpenStatement) {
+  SQLHSTMT statement;
+
+  // Connect string
+  std::string connect_str = this->GetConnectionString();
+  ASSERT_OK_AND_ASSIGN(std::wstring wconnect_str,
+                       arrow::util::UTF8ToWideString(connect_str));
+  std::vector<SQLWCHAR> connect_str0(wconnect_str.begin(), wconnect_str.end());
+
+  SQLWCHAR out_str[kOdbcBufferSize] = L"";
+  SQLSMALLINT out_str_len;
+
+  // Connecting to ODBC server.
+  ASSERT_EQ(SQL_SUCCESS,
+            SQLDriverConnect(this->conn, NULL, &connect_str0[0],
+                             static_cast<SQLSMALLINT>(connect_str0.size()), out_str,
+                             kOdbcBufferSize, &out_str_len, SQL_DRIVER_NOPROMPT))
+      << GetOdbcErrorMessage(SQL_HANDLE_DBC, this->conn);
+
+  // Allocate a statement using alloc statement
+  ASSERT_EQ(SQL_SUCCESS, SQLAllocStmt(this->conn, &statement));
+
+  // Disconnect from ODBC without closing the statement first
+  ASSERT_EQ(SQL_SUCCESS, SQLDisconnect(this->conn));
+}
+
 }  // namespace arrow::flight::sql::odbc