[Haskell-cafe] Re: haskelldb + sqlite problem.

GüŸnther Schmidt gue.schmidt at web.de
Mon Jun 22 17:39:44 EDT 2009

Hi John,

let me first of all apologize, I didn't mean to criticize you, I'm sure 
you had good reasons for those changes, I'm merely mean to state how 
they did affect me after switching to HDBC 2.1.

Since after the rollback they no longer occurred I surmise that there is 
a connection.

The error that Magicloud describes I recall only occurring when an 
umlaut in the path to the database file, that may or may not be due to 
the utf8-wrapping or it may just be a problem of the sqlite3.dll. No 
harm in trying if it can be solved this way by just moving the database 
file to one without any non-ascii characters. While I don't think that 
umlauts actually cause Magiclouds problem I did notice that he signs his 
emails with Chinese symbols, quite possible thus, that he has paths on 
his machine with non-ascii characters.


John Goerzen schrieb:
> Magicloud Magiclouds wrote:
>> Hi,
>>   I am using haskelldb and haskelldb-hdbc-sqlite3. Well, I finally got
>> the source compiled and ran, I got this error:
>> App: user error (SQL error: SqlError {seState = "", seNativeError =
>> 21, seErrorMsg = "prepare 74: SELECT subject,\n       timestamp\nFROM
>> notes as T1\nORDER BY timestamp DESC: library routine called out of
>> sequence"})
>>   Any clue what I should check? Thanks.
> At the HDBC level, I would say:
> I suspect that you have used a function that returns results lazily, but
> haven't completely read them before calling back into the database with
> something else.  As an example, you should probably use quickQuery'
> instead of quickQuery, unless you are fully prepared to accept the
> consequences of reading data lazily from a database.
> I am not very familiar with HaskellDB, and can't really comment on what
> it's doing under the hood.  If it is returning results to you lazily,
> make sure you have completely consumed them before sending more queries
> to the database.
> If you can post some example code, it would likely help.
> -- John

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