[erlang-questions] Erlang and MySQL: ODBC, Column type not supported

Hanfei Shen <>
Mon May 2 18:27:23 CEST 2011


Hi,

Hmmmmmm... The unixODBC is already in my system, but I don't know how
to use it...

I will setup a vm with fresh system tomorrow to reproduce the problem...

PS, could you figure out a name of ANOTHER ODBC-DRIVER which you mentioned?

2011/5/3 Hanfei Shen <>:
> Hi,
>
> I've tried https://github.com/dizzyd/erlang-mysql-driver, it works.
>
> I'm installing unixodbc... Wait a minute. Thnx...
>
>
> 2011/5/3 Ingela Andin <>:
>> Hi!
>>
>> Well the best thing would be if you can provide me with a way to reproduce it.
>> Do you have the possibility to try another odbc-driver with your database?
>>
>> Regards Ingela Erlang/OTP team - Ericsson AB
>>
>>
>> 2011/5/2 Hanfei Shen <>:
>>> Hi,
>>>
>>> I had changed the type from SQLINTEGER to SQLSMALLINT, but the problem
>>> is still there...
>>>
>>> (gdb) i func encode_data_type
>>> File odbcserver.c:
>>> static void encode_data_type(SQLSMALLINT, SQLINTEGER, SQLSMALLINT, db_state *);
>>>
>>> Breakpoint 1, encode_data_type (sql_type=-9, size=255,
>>> decimal_digits=0, state=0x7fffa5380210) at odbcserver.c:1396
>>> 1396        switch(sql_type) {
>>>
>>> Do you need any details?
>>>
>>> 2011/5/2 Ingela Anderton Andin <>:
>>>> Hi!
>>>>
>>>> Hanfei Shen wrote:
>>>>>
>>>>> Hi Ingela,
>>>>>
>>>>> Did you mean the value of variable "sql_type"?
>>>>>
>>>>>
>>>>
>>>> Yes.
>>>>
>>>>> I tried to inspect it through gdb, setting a break on func
>>>>> encode_data_type. And then I got:
>>>>>
>>>>> Breakpoint 1, encode_data_type (sql_type=-9, size=255,
>>>>> decimal_digits=0, state=0x7fffc657ec40) at odbcserver.c:1396
>>>>> 1396        switch(sql_type) {
>>>>>
>>>>>
>>>>
>>>> Well that is defenetly not a good value. Looking at the code just now
>>>> I noticed that
>>>>
>>>> encode_data_type defines sql_type as "SQLINTEGER sql_type" and it
>>>> ought to be "SQLSMALLINT sql_type". If you change that does it fix your
>>>> problem?
>>>>
>>>> Regards Ingela Erlang/OTP team - Ericsson AB
>>>>
>>>>
>>>>
>>>>> 2011/5/2 Ingela Andin <>:
>>>>>
>>>>>>
>>>>>> Hi!
>>>>>>
>>>>>> The erlang odbc application supports {sql-varchars,  N} where N = 255
>>>>>> in your case. The return values
>>>>>> you get suggest that the odbc-driver you have returns an unexpected
>>>>>> column type.
>>>>>>
>>>>>> In the erlang odbc port program there is a switch that handles type
>>>>>> when describing a coloumn that if we take out
>>>>>> the handling code looks like this.
>>>>>>
>>>>>> switch(sql_type) {
>>>>>>   case SQL_CHAR:
>>>>>>   case SQL_VARCHAR:
>>>>>>   case SQL_WCHAR:
>>>>>>   case SQL_WVARCHAR:
>>>>>>   case SQL_NUMERIC:
>>>>>>   case SQL_DECIMAL:
>>>>>>   case SQL_INTEGER:
>>>>>>   case SQL_TINYINT:
>>>>>>   case SQL_SMALLINT:
>>>>>>   case SQL_REAL:
>>>>>>   case SQL_FLOAT:
>>>>>>   case SQL_DOUBLE:
>>>>>>   case SQL_BIT:
>>>>>>   case SQL_TYPE_DATE:
>>>>>>   case SQL_TYPE_TIME:
>>>>>>   case SQL_TYPE_TIMESTAMP:
>>>>>>   case SQL_BIGINT:
>>>>>>   case SQL_BINARY:
>>>>>>   case SQL_LONGVARCHAR:
>>>>>>   case SQL_VARBINARY:
>>>>>>   case SQL_LONGVARBINARY:
>>>>>>   case SQL_INTERVAL_MONTH:
>>>>>>   case SQL_INTERVAL_YEAR:
>>>>>>   case SQL_INTERVAL_DAY:
>>>>>>   case SQL_INTERVAL_MINUTE:
>>>>>>   case SQL_INTERVAL_HOUR_TO_SECOND:
>>>>>>   case SQL_INTERVAL_MINUTE_TO_SECOND:
>>>>>>   case SQL_UNKNOWN_TYPE:
>>>>>>   default: /* Will probably never happen */
>>>>>>       ei_x_encode_atom(&dynamic_buffer(state), "ODBC_UNSUPPORTED_TYPE");
>>>>>>       break;
>>>>>>   }
>>>>>>
>>>>>>
>>>>>> And you end up in the default clause which is very unexpected and the
>>>>>> root to your problem.  If  you can figur out
>>>>>> what your driver returns for the ODBC C-API function SQLDescribeCol we
>>>>>> could know if the driver is at fault or if the odbc-port program is.
>>>>>>
>>>>>> Regards  Ingela Erlang/OTP team - Ericsson AB
>>>>>>
>>>>>> 2011/5/1 Hanfei Shen <>:
>>>>>>
>>>>>>>
>>>>>>> Dear all,
>>>>>>>
>>>>>>> I'm a newbie programming in erlang. When I used ODBC to connect to a
>>>>>>> MySQL database through Connector/ODBC (MyODBC), I got some error when
>>>>>>> calling odbc:sql_query(Conn, "SELECT * FROM action"):
>>>>>>>
>>>>>>> {error,"Column type not supported"}
>>>>>>>
>>>>>>> Then I call odbc:describe_table(Conn, "action"), it returned:
>>>>>>>
>>>>>>> {ok,[{"id",sql_integer},
>>>>>>>     {"code",'ODBC_UNSUPPORTED_TYPE'},
>>>>>>>     {"compliment_desc",'ODBC_UNSUPPORTED_TYPE'},
>>>>>>>     {"status_desc",'ODBC_UNSUPPORTED_TYPE'},
>>>>>>>     {"parameter",'ODBC_UNSUPPORTED_TYPE'},
>>>>>>>     {"cause",'ODBC_UNSUPPORTED_TYPE'},
>>>>>>>     {"disabled",sql_tinyint}]}
>>>>>>>
>>>>>>> And desc the table in mysql client:
>>>>>>> mysql> desc action;
>>>>>>>
>>>>>>> +-----------------+--------------+------+-----+---------+----------------+
>>>>>>> | Field           | Type         | Null | Key | Default | Extra
>>>>>>>  |
>>>>>>>
>>>>>>> +-----------------+--------------+------+-----+---------+----------------+
>>>>>>> | id              | int(11)      | NO   | PRI | NULL    | auto_increment
>>>>>>> |
>>>>>>> | code            | varchar(255) | NO   |     | NULL    |
>>>>>>>  |
>>>>>>> | compliment_desc | varchar(255) | NO   |     |         |
>>>>>>>  |
>>>>>>> | status_desc     | varchar(255) | NO   |     |         |
>>>>>>>  |
>>>>>>> | parameter       | varchar(255) | NO   |     |         |
>>>>>>>  |
>>>>>>> | cause           | varchar(255) | NO   | UNI |         |
>>>>>>>  |
>>>>>>> | disabled        | tinyint(1)   | NO   |     | 0       |
>>>>>>>  |
>>>>>>>
>>>>>>> +-----------------+--------------+------+-----+---------+----------------+
>>>>>>>
>>>>>>> It seems that Erlang ODBC driver does not support the mysql type
>>>>>>> varchar? How can I use the database without touching the db schema?
>>>>>>>
>>>>>>>
>>>>>>> Some details about the system env:
>>>>>>>
>>>>>>> $ uname -a
>>>>>>> Linux 2.6.36-gentoo-r8 #4 SMP Thu Apr 7 20:13:18 CST 2011 x86_64
>>>>>>> Intel(R) Core(TM)2 Duo CPU E7500 @ 2.93GHz GenuineIntel GNU/Linux
>>>>>>>
>>>>>>> $ erl
>>>>>>> Erlang R13B04 (erts-5.7.5) [source] [64-bit] [smp:2:2] [rq:2]
>>>>>>> [async-threads:0] [kernel-poll:false]
>>>>>>>
>>>>>>> $ emerge -vp erlang
>>>>>>> dev-lang/erlang-13.2.4  USE="doc kpoll odbc smp ssl -emacs -hipe -java
>>>>>>> -sctp -tk -wxwidgets"
>>>>>>>
>>>>>>> eshell> code:which(odbc).
>>>>>>> "/usr/lib64/erlang/lib/odbc-2.10.7/ebin/odbc.beam"
>>>>>>>
>>>>>>> $ mysql -V
>>>>>>> mysql  Ver 14.14 Distrib 5.1.51, for pc-linux-gnu (x86_64) using
>>>>>>> readline 5.1
>>>>>>>
>>>>>>> Server version: 5.1.51-log Gentoo Linux mysql-5.1.51
>>>>>>>
>>>>>>> $ emerge -vp myodbc
>>>>>>> dev-db/myodbc-5.1.6  USE="-debug -doc -qt4 -static"
>>>>>>>
>>>>>>>
>>>>>>> Any help will be greatly appreciated.  Thanks in advance.
>>>>>>> Sorry for my poor English, I'm not a native...
>>>>>>>
>>>>>>> Best,
>>>>>>>
>>>>>>> --
>>>>>>> Hanfei
>>>>>>> _______________________________________________
>>>>>>> erlang-questions mailing list
>>>>>>> 
>>>>>>> http://erlang.org/mailman/listinfo/erlang-questions
>>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>> _______________________________________________
>>> erlang-questions mailing list
>>> 
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>>>
>>
>



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