> So, is there a way I can tell SQLite to preserve the data size in a > particular column?
As long as you use blobs to store your structs, yes you can tell SQLite to preserve data size. You cannot do that for any other type, but it sounds like you don't need any other type because all you need is to store your structs in binary format. But in this case be aware of endianness and alignment issues that can be different on different platforms with different compilers. So my good advice will be: rethink your pattern of working with data to avoid using "pointer to struct" and "struct size" but use real data values instead. Pavel On Mon, Mar 29, 2010 at 4:19 PM, Kevin M. <athlo...@yahoo.com> wrote: > I have a C/C++ application in which I want to store data from a struct into a > table (using SQLite 3.6.23) and later retrieve data from the table and store > it back in the struct. But, I need a general interface for this as there are > many types of structs used. So, what I have is a function that accepts a > pointer to the struct (ptr), the struct size, and a sqlite3_stmt* variable > for the current row. I then iterate through each column of the row and store > the value retrieved at ptr's address. Then I increment ptr based on the size > of the column. Thus, as long as I store and retrieve columns in the same > order I should be storing the right values in the right variables for a > particular struct instance. > > However, this method breaks down if a store a 16-bit integer value like "99" > and SQLite stores it internally as an 8-bit value (to save space) and > subsequently retrieves it and gives me a value of 1 for > sqlite3_column_bytes(). This causes alignment issues with the variables in > the struct. So, is there a way I can tell SQLite to preserve the data size > in a particular column? E.g.: > > CREATE TABLE test ( val1 INTEGER, val2 INT2, val3 INT1 ... ); > > Here val1 is always 4-bytes, val2 is always 2 bytes, and val3 is always 1 > byte. > > I'd prefer a way to do this without having to cast every last column in a > SELECT query to the right size. > > Hopefully that made sense. > > Thanks, > Kevin > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
