Hi, all.
How about this approach?
I just implemented a simple code(User Defined Function) that returns a
number as like as row number.
It was worked pretty good with my simple SQL test cases.
sqlite> insert into test values ('first record');
sqlite> insert into test values ('second record');
sqlite> insert into test values ('third record');
sqlite> select rownum(0), * from test;
1 | first record
2 | second record
3 | third record
Note. parameter value of 0 is not necessary, but it should be exist to work
properly to use aux data in UDF.
Below shows my code.
It is registered by calling sqlite3_create_function() after database is
opened.
typedef struct ROWNUM_t ROWNUM_t;
struct ROWNUM_t{
int nNumber;
};
static void rownum_free(void *p){
sqlite3_free(p);
}
static void rownum(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
ROWNUM_t* pAux;
pAux = sqlite3_get_auxdata(context, 0);
if(!pAux) {
pAux = (ROWNUM_t*)sqlite3_malloc(sizeof(ROWNUM_t));
if(pAux) {
pAux->nNumber = 0;
sqlite3_set_auxdata(context, 0, (void*)pAux, rownum_free);
}
else {
sqlite3_result_error(context, "sqlite3_malloc failed", -1);
return;
}
}
pAux->nNumber++;
sqlite3_result_int(context, pAux->nNumber);
}
Regards,
Yongil.
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