On 9/13/17, Stadin, Benjamin <benjamin.sta...@heidelberg-mobil.com> wrote: > Hi, > > I was missing a few records in my program. After debugging further, I found > that sqlite3_column_type () returns SQLITE_NULL for some objects (like 10 in > 2000), even though these actually contain text data. > > Is this normal? And how should I handle it properly (I mean, check if it’s > proper 0 escaped text for example)?
This is normal. The sqlite3_value object contains only a NULL, not any text or numbers. Internally, the sqlite3_value object caches some things that helps SQLite to run faster, and some of those cached buffers might be holding the remains of stale string values. Ignore all of that - it is junk at this point. The only thing that matters in your sqlite3_value dump below is the "flags" field, which has a value of 0x0001, which indicates a NULL (https://sqlite.org/src/artifact/1fe007701?ln=234) Please note that all this is an implementation detail which often changes from one release to the next. The dump of the sqlite3_value object shown below is valid only for the specific version of SQLite you are debugging, and might be very different for other versions of SQLite. When you start digging down into the content of the sqlite3_value object, you are looking into low-level implementation details of SQLite. This is something that application developers need not worry with. You are welcomed to poke around if you want, but please know that it is not expected nor necessary and that very few application-level developers get into that much detail, especially considering that everything you learn will likely be different the next time you upgrade your SQLite version. > > Below is an example object returned by sqlite3_column_value() which is > reported as SQLITE_NULL. > > I’m using the latest SQLite 3.20.1. > > Thanks > Ben > > val sqlite3_value * 0x10201a618 0x000000010201a618 > u MemValue > flags u16 1 > enc u8 '\x01' > eSubtype u8 '\0' > n int 6 > z char * "BB.999" 0x000000010201e340 > zMalloc char * "BB.999" 0x000000010201e340 > szMalloc int 1200 > uTemp u32 0 > db sqlite3 * 0x100406f10 0x0000000100406f10 > xDel void (*)(void *) NULL 0x0000000000000000 > > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
