On Jan 29, 2010, at 1:17 PM, Joost wrote:
> Hi all,
>
> at first i want to say a big "Thank you" to all sqlite developers.
> Using
> sqlite with Python since 4 years i always (when suited) announce
> sqlite
> in my examples for great open source software - indeed i see it as
> one
> of the best pieces of software in the world.
>
> The same can be said for the C-API, everything works easy and as
> expected. Currently i work on database bound Python containers, the
> base class "lineup" having all the stuff for Python subscription,
> iteration and
> so on. It supports coding of this kind (with lu a "litelineup"):
>
> lu.dump("testdump.db3", "A"); lu.clear()
> lu.connect("testdump.db3", "A")
> lu.select("LIMIT 3"); print(lu); lu.hangup()
>
> Special convenince has litelineup.update(): Litelineup tracks cell
> modifications and writes them back so, being connected not only to
> a database, but having the notion of an associated table too.
>
> These convenient methods as litelineup.select(whereclause),
> litelinup.update(), litelineup.insert_keys(keys) and so on are not
> only for
> programmer's convenience, but also reuse prepared statements -
> litelineup has no general statement cache, but some frequently used
> prepared statements as (only internal) object attributes.
>
> Thus litelineup.hangup() must finalize them:
>
> PyObject *LiteLineUp_HangUp(litelineup *self) {
> Py_ssize_t i = 0;
> // if (self->COMMIT_stmt) sqlite3_finalize(self->COMMIT_stmt);
> while (L3LSELF->update_stmts[i++])
> sqlite3_finalize(L3LSELF->update_stmts[i]);
> PyMem_Resize(L3LSELF->update_stmts, sqlite3_stmt*, 1);
> L3LSELF->update_stmts[0] = NULL;
> if (self->select_keys) sqlite3_finalize(self->select_keys); //
> sqlite3_stmt
> refers a connection
> if (self->select_glob) sqlite3_finalize(self->select_glob);
> if (self->insert_keys) sqlite3_finalize(self->insert_keys);
> // if (self->BEGIN_stmt) sqlite3_finalize(self->BEGIN_stmt);
> if (self->conn) { sqlite3_close(self->conn); self->conn=NULL; }
> Py_RETURN_NONE;
> }
>
> You see the uncommented rows for COMMIT_stmt and BEGIN_stmt.
> Indeed performing these lines crashes the litelineup. Is it true, that
> we must not finalize a statement prepared by
>
> sqlite3_prepare_v2(self->conn, "COMMIT ;", -1, &self->COMMIT_stmt,
> NULL);
>
> or BEGIN IMMEDIATE ?
No. Same rules apply as for all other statements. Each successful call
to sqlite3_prepare_v2() must be matched by an sqlite3_finalize().
Dan.
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