//Dear there, it seems that I cannot insert
std::numeric_limits<double>::max(). I am on Mac Osx 10.5
//anybody can take a look at the code? I am new to sqlite3. comments on
coding also welcome.
#include <string>
#include <iostream>
#include <cassert>
#include <sqlite3.h>
using namespace std;
int main(){
double infinity = std::numeric_limits<double>::max();
double ninfinity = std::numeric_limits<double>::min();
sqlite3 *db;
char *zErrMsg = 0;
int rc;
rc = sqlite3_open(":memory:", &db);
if( rc ){
fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
sqlite3_close(db);
exit(1);
}
sqlite3_stmt* create_tl;
rc = sqlite3_prepare_v2(db, "create table tl (number real)", -1,
&create_tl,NULL);
printf("%i\n",rc);
if ( rc != SQLITE_OK) exit(rc);
rc = sqlite3_step(create_tl);
if ( rc != SQLITE_DONE) exit(rc);
sqlite3_stmt* insert_tl;
rc = sqlite3_prepare_v2(db,"insert into tl values(:number)",-1,
&insert_tl,NULL);
if ( rc != SQLITE_OK) exit(rc);
sqlite3_bind_double(insert_tl, 1, 1.1);
rc = sqlite3_step(insert_tl);
if (rc != SQLITE_DONE)
exit(rc);
sqlite3_bind_double(insert_tl, 1, infinity); //this line would fail,
error code 21
rc = sqlite3_step(insert_tl);
if (rc != SQLITE_DONE)
exit(rc);
sqlite3_bind_double(insert_tl, 1, ninfinity);
rc = sqlite3_step(insert_tl);
if (rc != SQLITE_DONE)
exit(rc);
sqlite3_bind_double(insert_tl, 1, 3.3);
rc = sqlite3_step(insert_tl);
if (rc != SQLITE_DONE)
exit(rc);
sqlite3_stmt* select_tl;
rc = sqlite3_prepare_v2(db, "select * from tl",-1,&select_tl,NULL);
if (rc != SQLITE_OK)
exit(rc);
while ( sqlite3_step(select_tl) == SQLITE_ROW){
printf("%e",sqlite3_column_double(select_tl,0));
printf("\n");
}
if (rc != SQLITE_DONE)
exit(rc);
sqlite3_finalize(select_tl);
sqlite3_close(db);
printf("exit normally\n");
}
On Sun, Oct 18, 2009 at 5:58 PM, John Crenshaw <[email protected]>wrote:
> SQLite stores the data however you give it. I'm not aware of any
> documentation requiring that 9e999 be considered infinity, nor any
> requiring that the command line treat invalid numbers as null. Most
> likely, treating NaN as null is simply a way for the command line to
> behave reasonably in an otherwise undefined situation.
>
> Practically, 9e999 is beyond the "infinity" limit for doubles on
> whatever compiler was used to build the command line. I think this limit
> is technically arbitrary, so on some compilers, either now, or in the
> future, 9e999 could very possibly NOT be infinity.
> std::numeric_limits<double>::max() should be a standard (read "safe")
> way of getting the "infinity" value in C++.
>
> In the Visual C++ 2005 compiler, the max double is
> 1.7976931348623158e+308. I'm not sure that this is constant however, so
> don't count on it.
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Michael Chen
> Sent: Sunday, October 18, 2009 4:19 PM
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Infinity
>
>
> I am looking for the answer too. anybody know it?
>
> On Sat, Oct 17, 2009 at 12:23 AM, Dan Bishop <[email protected]>
> wrote:
>
> > I've noticed that I can use IEEE Infinity values in SQLite by writing
> > any literal too big for a double.
> >
> > sqlite> CREATE TABLE foo (x REAL);
> > sqlite> INSERT INTO foo VALUES (9e999); -- +Inf
> > sqlite> INSERT INTO foo VALUES (-9e999); -- -Inf
> > sqlite> INSERT INTO foo VALUES (9e999 / 9e999); -- NaN: gets converted
> > to NULL
> > sqlite> .null NULL
> > sqlite> select * FROM foo;
> > Inf
> > -Inf
> > NULL
> > sqlite> SELECT * FROM foo WHERE ABS(x) = 9e999;
> > Inf
> > -Inf
> >
> > Is it true on all platforms that 9e999 = Infinity and CAST(9e999 AS
> > TEXT) = 'Inf'? What's the preferred SQL syntax for infinity?
> > _______________________________________________
> > sqlite-users mailing list
> > [email protected]
> > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
> >
>
>
>
> --
> Best regards,
> Michael Chen
> Google Voice Phone.: 847-448-0647
> _______________________________________________
> sqlite-users mailing list
> [email protected]
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
> _______________________________________________
> sqlite-users mailing list
> [email protected]
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
--
Best regards,
Michael Chen
Google Voice Phone.: 847-448-0647
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