rem: int db_update(db_con_t* _h, db_key_t* _k, db_op_t* _o, db_val_t* _v, db_key_t* _uk, db_val_t* _uv, int _n, int _un)
add: int db_update(db_con_t* con, db_key_t* keys, db_op_t* ops, db_val_t* vals, db_key_t* ucols, db_val_t* uvals, int n, int un)
context: int db_update(db_con_t* _h, db_key_t* _k, db_op_t* _o, db_val_t* _v,	      db_key_t* _uk, db_val_t* _uv, int _n, int _un){	int off;	off = snprintf(sql_buf, SQL_BUF_LEN, "update %s set ", CON_TABLE(_h));	off += print_set(sql_buf + off, SQL_BUF_LEN - off, _uk, _uv, _un);	if (_n) {		off += snprintf(sql_buf + off, SQL_BUF_LEN - off, " where ");		off += print_where(sql_buf + off, SQL_BUF_LEN - off, _k,			_o, _v, _n);		*(sql_buf + off) = '\0';	}	if(begin_transaction(_h, sql_buf)) return(-1);	if (submit_query(_h, sql_buf) < 0) {		LOG(L_ERR, "db_update(): Error while updating\n");		return -2;	}	free_query(_h);	commit_transaction(_h);	return(0);}