SQLite not performing update

I have a table representing a hierarchy using the nested set model, declared as

Code:

---

CREATE TABLE tags (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        label TEXT NOT NULL UNIQUE,
        lft INTEGER NOT NULL,
        rgt INTEGER NOT NULL
);

---

I have implemented functionality for adding, removing and renaming entries. When I got to implementing the function for changing the parent of an entry the SQL UPDATE-statements just aren't being performed.
The part of the code that does the updating looks like this:

Code:

---

/* Earlier declarations. */
const char* updates[] = {
        "UPDATE tags SET lft = CASE WHEN lft BETWEEN ? AND ?"
        "        THEN lft + ? ELSE lft + ?"
        "END WHERE lft BETWEEN ? AND ?",

        "UPDATE tags SET rgt = CASE WHEN rgt BETWEEN ? AND ?"
        "        THEN rgt + ? ELSE rgt + ?"
        "END WHERE rgt BETWEEN ? AND ?"
};
sqlite3_stmt* stmt;
int src_lft, src_rgt, dest_rgt;
int affected_lft, affected_rgt;
int move, displacement;
int i;

/* The update statements being run at the end of the function. */
for (i = 0; i < sizeof(updates)/sizeof(*updates); i++) {
        sqlite3_prepare_v2(db, updates[i], -1, &stmt, NULL);
        sqlite3_bind_int(stmt, 1, src_lft);
        sqlite3_bind_int(stmt, 2, src_rgt);
        sqlite3_bind_int(stmt, 3, move);
        sqlite3_bind_int(stmt, 4, displacement);
        sqlite3_bind_int(stmt, 5, affected_lft);
        sqlite3_bind_int(stmt, 6, affected_rgt);
        sqlite3_step(stmt);
        sqlite3_finalize(stmt);
}

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The values put into the prepared statements are correct, and all the sqlite3 function calls return SQLITE_OK, except step which returns SQLITE_DONE, so everything seems to be in order. But when inspecting the database afterwards no actual change have been made.

I have test program construct a test database which looks like this.

Code:

---

$ sqlite3 test.db "SELECT * FROM tags"
1|colors|1|14
2|green|2|7
3|light green|3|4
4|dark green|5|6
5|red|8|13
6|pink|9|10
7|magenta|11|12

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In the test program I want to set red's parent to green, which has proved to be difficult. If I create a new database, where I add the elements so that this is the case (the add function can add a new entry with a specified parent), I get the following database.

Code:

---

$ sqlite3 test.db "SELECT * FROM tags"
1|colors|1|14
2|green|2|13
3|light green|3|4
4|dark green|5|6
5|red|7|12
6|pink|8|9
7|magenta|10|11

---

Now, take the original database and do the UPDATE statements by hand with the sqlite3 program and you get...

Code:

---

$ sqlite3 test.db "UPDATE tags SET lft = CASE WHEN lft BETWEEN 8 AND 13 THEN lft + (-1) ELSE lft + 6 END WHERE lft BETWEEN 7 AND 13"
$ sqlite3 test.db "UPDATE tags SET rgt = CASE WHEN rgt BETWEEN 8 AND 13 THEN rgt + (-1) ELSE rgt + 6 END WHERE rgt BETWEEN 7 AND 13"
$ sqlite3 test.db "SELECT * FROM tags"
1|colors|1|14
2|green|2|13
3|light green|3|4
4|dark green|5|6
5|red|7|12
6|pink|8|9
7|magenta|10|11

---

The exact same database as the previously constructed one. The constants were taken as they were printed out from the function which is supposed to change parent, so it should be the same semantics. Bear in mind that UPDATE statements work fine in all the other functions I use them in.

I really have no clue what could be wrong here. I'm using MinGW and generated the sqlite3 library using dlltool.