Re: [sqlite] Prepare statement in separate function

[Igor Tandetnik]

enjoythe...@hushmail.com wrote:
> I was allocating memory because I wanted to prepare the statement
> in a separate function.

Just prepare the statement, and return sqlite3_stmt* by value. You are not 
allocating memory when returning, say, an int, right? sqlite3_stmt* is 
comparable in size, and can be treated similarly.
-- 
Igor Tandetnik

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Re: [sqlite] Prepare statement in separate function

[enjoythesun]

hello martin,

I was allocating memory because I wanted to prepare the statement 
in a separate function. After all I have changed the whole 
implementation design to something less awkward :)

greetings,
john

On Tue, 11 Oct 2011 11:46:01 +0200 Martin Engelschalk 
 wrote:
>Hello John,
>
>why do you malloc() your DB- and Statement handle?
>
>I  declare a
>
>sqlite3* pDB;
>sqlite3_stmt* pStmnt;
>
>then open the database with
>
>int nRet = sqlite3_open("MyDatabaseName", );
>
>and prepare a statement using
>
>nRet = sqlite3_prepare_v2(pDB, "insert .", -1, , 
>);
>
>no need to malloc (or free) anything, and passing pDB or pStmnt to 
>
>functions is easy.
>
>Martin
>
>
>Am 11.10.2011 11:27, schrieb enjoythe...@hushmail.com:
>> hello list,
>>
>> I have a question regarding prepared statements. I'm fairly new 
>to
>> sqlite3 and it's already pretty late, so if I'm overlooking
>> something obvious please forgive me :) I'm on Windows 7 x64 and
>> using sqlite-3070800 (amalgamation).
>>
>> I'm trying to prepare an insert statement, that I will reuse 
>many
>> times using bound parameters. In a short test application, if I
>> prepare the statement within the main function everything is 
>fine:
>>
>> CODE
>> ...
>> int rc=0;
>> pDb = (sqlite3*) malloc (sizeof(sqlite3*));
>> stmt = (sqlite3_stmt*) malloc (sizeof(sqlite3_stmt*));
>> ...
>>
>> if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1,, NULL)) !=
>> SQLITE_OK){
>>  /* ... error ... */
>> }
>>
>> sqlite3_step(stmt);
>> ...
>> \CODE
>>
>> However, if I try throw this code in a separate function like 
>this,
>>
>> CODE
>> int prepareStatement(sqlite3_stmt* stmt, sqlite3* pDb){
>>
>>  int rc=0;
>>
>>  if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1,, NULL)) 
>!=
>> SQLITE_OK){
>>  /* ... error ... */
>>  }
>>  return 0;
>> }
>> \CODE
>>
>> it fails as soon as I call sqlite3_step(stmt) afterwards. The
>> debugger stops at:
>>
>> sqlite3_mutex_enter(db->mutex);
>>
>> At first I thought I was doing smthg wrong during memory
>> allocation, but everything seems to be fine there. I'm sure I'm
>> overlooking an obvious mistake. Maybe somebody can give me a 
>hint!
>>
>> thanks,
>> John
>>
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Re: [sqlite] Prepare statement in separate function

[Martin Engelschalk]

Hello John,

why do you malloc() your DB- and Statement handle?

I  declare a

sqlite3* pDB;
sqlite3_stmt* pStmnt;

then open the database with

int nRet = sqlite3_open("MyDatabaseName", );

and prepare a statement using

nRet = sqlite3_prepare_v2(pDB, "insert .", -1, , );

no need to malloc (or free) anything, and passing pDB or pStmnt to 
functions is easy.


Martin


Am 11.10.2011 11:27, schrieb enjoythe...@hushmail.com:

hello list,

I have a question regarding prepared statements. I'm fairly new to
sqlite3 and it's already pretty late, so if I'm overlooking
something obvious please forgive me :) I'm on Windows 7 x64 and
using sqlite-3070800 (amalgamation).

I'm trying to prepare an insert statement, that I will reuse many
times using bound parameters. In a short test application, if I
prepare the statement within the main function everything is fine:

CODE
...
int rc=0;
pDb = (sqlite3*) malloc (sizeof(sqlite3*));
stmt = (sqlite3_stmt*) malloc (sizeof(sqlite3_stmt*));
...

if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1,, NULL)) !=
SQLITE_OK){
/* ... error ... */
}

sqlite3_step(stmt);
...
\CODE

However, if I try throw this code in a separate function like this,

CODE
int prepareStatement(sqlite3_stmt* stmt, sqlite3* pDb){

int rc=0;

if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1,, NULL)) !=
SQLITE_OK){
/* ... error ... */
}
return 0;
}
\CODE

it fails as soon as I call sqlite3_step(stmt) afterwards. The
debugger stops at:

sqlite3_mutex_enter(db->mutex);

At first I thought I was doing smthg wrong during memory
allocation, but everything seems to be fine there. I'm sure I'm
overlooking an obvious mistake. Maybe somebody can give me a hint!

thanks,
John

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Re: [sqlite] Prepare statement in separate function

[enjoythesun]

hello again,

ok, right after posting to the list, I have found the mistake. 
Obviously it needs to be:

sqlite3_stmt** stmt = (sqlite3_stmt**) malloc 
(sizeof(sqlite3_stmt*));

thanks list! :)


On Tue, 11 Oct 2011 11:27:41 +0200 enjoythe...@hushmail.com wrote:
>hello list,
>
>I have a question regarding prepared statements. I'm fairly new to 
>
>sqlite3 and it's already pretty late, so if I'm overlooking 
>something obvious please forgive me :) I'm on Windows 7 x64 and 
>using sqlite-3070800 (amalgamation).
>
>I'm trying to prepare an insert statement, that I will reuse many 
>times using bound parameters. In a short test application, if I 
>prepare the statement within the main function everything is fine:
>
>CODE
>...
>int rc=0;
>pDb = (sqlite3*) malloc (sizeof(sqlite3*));
>stmt = (sqlite3_stmt*) malloc (sizeof(sqlite3_stmt*));
>...
>
>if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1, , NULL)) != 
>SQLITE_OK){
>   /* ... error ... */
>}
>
>sqlite3_step(stmt);
>...
>\CODE
>
>However, if I try throw this code in a separate function like 
>this,
>
>CODE
>int prepareStatement(sqlite3_stmt* stmt, sqlite3* pDb){
>
>   int rc=0;
>
>   if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1, , NULL)) != 
>
>SQLITE_OK){
>   /* ... error ... */
>   }
>   return 0;
>}
>\CODE
>
>it fails as soon as I call sqlite3_step(stmt) afterwards. The 
>debugger stops at:
>
>sqlite3_mutex_enter(db->mutex);
>
>At first I thought I was doing smthg wrong during memory 
>allocation, but everything seems to be fine there. I'm sure I'm 
>overlooking an obvious mistake. Maybe somebody can give me a hint!
>
>thanks,
>John
>
>___
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[sqlite] Prepare statement in separate function

[enjoythesun]

hello list,

I have a question regarding prepared statements. I'm fairly new to 
sqlite3 and it's already pretty late, so if I'm overlooking 
something obvious please forgive me :) I'm on Windows 7 x64 and 
using sqlite-3070800 (amalgamation).

I'm trying to prepare an insert statement, that I will reuse many 
times using bound parameters. In a short test application, if I 
prepare the statement within the main function everything is fine:

CODE
...
int rc=0;
pDb = (sqlite3*) malloc (sizeof(sqlite3*));
stmt = (sqlite3_stmt*) malloc (sizeof(sqlite3_stmt*));
...

if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1, , NULL)) != 
SQLITE_OK){
/* ... error ... */
}

sqlite3_step(stmt);
...
\CODE

However, if I try throw this code in a separate function like this,

CODE
int prepareStatement(sqlite3_stmt* stmt, sqlite3* pDb){

int rc=0;

if((rc=sqlite3_prepare_v2(pDb, INSERT_STMT , -1, , NULL)) != 
SQLITE_OK){
/* ... error ... */
}
return 0;
}
\CODE

it fails as soon as I call sqlite3_step(stmt) afterwards. The 
debugger stops at:

sqlite3_mutex_enter(db->mutex);

At first I thought I was doing smthg wrong during memory 
allocation, but everything seems to be fine there. I'm sure I'm 
overlooking an obvious mistake. Maybe somebody can give me a hint!

thanks,
John

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