diff --git a/driver/odbc.c b/driver/odbc.c
index e375df0d..cf1a9fdd 100644
--- a/driver/odbc.c
+++ b/driver/odbc.c
@@ -898,12 +898,12 @@ SQLRETURN  SQL_API SQLFetchScroll(SQLHSTMT StatementHandle,
 	SQLSMALLINT FetchOrientation, SQLLEN FetchOffset)
 {
 	SQLRETURN ret;
-	TRACE(_IN, StatementHandle, "phz", StatementHandle,
+	TRACE3(_IN, StatementHandle, "phz", StatementHandle,
 		FetchOrientation, FetchOffset);
 	HND_LOCK(StatementHandle);
 	ret = EsSQLFetchScroll(StatementHandle, FetchOrientation, FetchOffset);
 	HND_UNLOCK(StatementHandle);
-	TRACE(_OUT, StatementHandle, "dphz", ret, StatementHandle,
+	TRACE4(_OUT, StatementHandle, "dphz", ret, StatementHandle,
 		FetchOrientation, FetchOffset);
 	return ret;
 }
diff --git a/driver/queries.c b/driver/queries.c
index 08c7a240..90a4d54d 100644
--- a/driver/queries.c
+++ b/driver/queries.c
@@ -109,6 +109,7 @@ static SQLRETURN attach_columns(esodbc_stmt_st *stmt, UJObject columns)
 		MK_WPTR(JSON_ANSWER_COL_NAME),
 		MK_WPTR(JSON_ANSWER_COL_TYPE)
 	};
+	static const wstr_st EMPTY_WSTR = WSTR_INIT("");
 
 	ird = stmt->ird;
 	dbc = stmt->hdr.dbc;
@@ -180,15 +181,23 @@ static SQLRETURN attach_columns(esodbc_stmt_st *stmt, UJObject columns)
 		/* "If a base column name does not exist (as in the case of columns
 		 * that are expressions), then this variable contains an empty
 		 * string." */
-		rec->base_column_name = MK_WSTR("");
+		rec->base_column_name = EMPTY_WSTR;
 		/* "If a column does not have a label, the column name is returned. If
 		 * the column is unlabeled and unnamed, an empty string is ret" */
-		rec->label = rec->name.cnt ? rec->name : MK_WSTR("");
+		rec->label = rec->name.cnt ? rec->name : EMPTY_WSTR;
 
 		assert(rec->name.str && rec->label.str);
 		rec->unnamed = (rec->name.cnt || rec->label.cnt) ?
 			SQL_NAMED : SQL_UNNAMED;
 
+		/* All rec fields must be init'ed to a valid string in case their value
+		 * is requested (and written with write_wstr()). The values would
+		 * normally be provided by the data source, this is not the case here
+		 * (yet), though. */
+		rec->base_table_name = EMPTY_WSTR;
+		rec->catalog_name = EMPTY_WSTR;
+		rec->schema_name = EMPTY_WSTR;
+		rec->table_name = EMPTY_WSTR;
 #ifndef NDEBUG
 		//dump_record(rec);
 #endif /* NDEBUG */
diff --git a/driver/util.c b/driver/util.c
index e1aabf59..ea936b9d 100644
--- a/driver/util.c
+++ b/driver/util.c
@@ -566,6 +566,7 @@ SQLRETURN write_wstr(SQLHANDLE hnd, SQLWCHAR *dest, wstr_st *src,
 				LWSTR(src), src->cnt, wide_avail);
 			RET_HDIAGS(hnd, SQL_STATE_01004);
 		} else {
+			assert(src->str);
 			wcsncpy(dest, src->str, src->cnt + /* 0-term */1);
 		}
 	} else {