[td-10869] add two new APIs in taos.h.

src/client/src/tscSql.c

@@ -777,6 +777,16 @@ bool taos_is_null(TAOS_RES *res, int32_t row, int32_t col) {
   return isNull(((char*) pSql->res.urow[col]) + row * pInfo->field.bytes, pInfo->field.type);
 }
 
+bool taos_is_update_query(TAOS_RES *res) {
+  SSqlObj *pSql = (SSqlObj *)res;
+  if (pSql == NULL || pSql->signature != pSql) {
+    return false;
+  }
+
+  SSqlCmd* pCmd = &pSql->cmd;
+  return ((pCmd->command >= TSDB_SQL_INSERT && pCmd->command <= TSDB_SQL_DROP_DNODE) || TSDB_SQL_RESET_CACHE == pCmd->command || TSDB_SQL_USE_DB == pCmd->command);
+}
+
 int taos_print_row(char *str, TAOS_ROW row, TAOS_FIELD *fields, int num_fields) {
   int len = 0;
 
@@ -905,7 +915,6 @@ int taos_validate_sql(TAOS *taos, const char *sql) {
 
   strtolower(pSql->sqlstr, sql);
 
-//  pCmd->curSql = NULL;
   if (NULL != pCmd->insertParam.pTableBlockHashList) {
     taosHashCleanup(pCmd->insertParam.pTableBlockHashList);
     pCmd->insertParam.pTableBlockHashList = NULL;
@@ -930,6 +939,17 @@ int taos_validate_sql(TAOS *taos, const char *sql) {
   return code;
 }
 
+void taos_reset_current_db(TAOS *taos) {
+  STscObj* pObj = (STscObj*) taos;
+  if (pObj == NULL || pObj->signature != pObj) {
+    return;
+  }
+
+  pthread_mutex_lock(&pObj->mutex);
+  memset(pObj->db, 0, tListLen(pObj->db));
+  pthread_mutex_unlock(&pObj->mutex);
+}
+
 void loadMultiTableMetaCallback(void *param, TAOS_RES *res, int code) {
   SSqlObj* pSql = (SSqlObj*)taosAcquireRef(tscObjRef, (int64_t)param);
   if (pSql == NULL) {

src/inc/taos.h

@@ -175,11 +175,13 @@ DLL_EXPORT int taos_select_db(TAOS *taos, const char *db);
 DLL_EXPORT int taos_print_row(char *str, TAOS_ROW row, TAOS_FIELD *fields, int num_fields);
 DLL_EXPORT void taos_stop_query(TAOS_RES *res);
 DLL_EXPORT bool taos_is_null(TAOS_RES *res, int32_t row, int32_t col);
+DLL_EXPORT bool taos_is_update_query(TAOS_RES *res);
 DLL_EXPORT int taos_fetch_block(TAOS_RES *res, TAOS_ROW *rows);
-DLL_EXPORT int taos_validate_sql(TAOS *taos, const char *sql);
-
 DLL_EXPORT int* taos_fetch_lengths(TAOS_RES *res);
 
+DLL_EXPORT int taos_validate_sql(TAOS *taos, const char *sql);
+DLL_EXPORT void taos_reset_current_db(TAOS *taos);
+
 // TAOS_RES   *taos_list_tables(TAOS *mysql, const char *wild);
 // TAOS_RES   *taos_list_dbs(TAOS *mysql, const char *wild);
 
@@ -192,7 +194,6 @@ DLL_EXPORT int taos_errno(TAOS_RES *tres);
 
 DLL_EXPORT void taos_query_a(TAOS *taos, const char *sql, void (*fp)(void *param, TAOS_RES *, int code), void *param);
 DLL_EXPORT void taos_fetch_rows_a(TAOS_RES *res, void (*fp)(void *param, TAOS_RES *, int numOfRows), void *param);
-//DLL_EXPORT void taos_fetch_row_a(TAOS_RES *res, void (*fp)(void *param, TAOS_RES *, TAOS_ROW row), void *param);
 
 typedef void (*TAOS_SUBSCRIBE_CALLBACK)(TAOS_SUB* tsub, TAOS_RES *res, void* param, int code);
 DLL_EXPORT TAOS_SUB *taos_subscribe(TAOS* taos, int restart, const char* topic, const char *sql, TAOS_SUBSCRIBE_CALLBACK fp, void *param, int interval);