Invert A Changeset

Invert A Changeset

int sqlite3changeset_invert(
  int nIn, const void *pIn,       /* Input changeset */
  int *pnOut, void **ppOut        /* OUT: Inverse of input */
);

This function is used to "invert" a changeset object. Applying an inverted changeset to a database reverses the effects of applying the uninverted changeset. Specifically:

• Each DELETE change is changed to an INSERT, and
• Each INSERT change is changed to a DELETE, and
• For each UPDATE change, the old.* and new.* values are exchanged.

This function does not change the order in which changes appear within the changeset. It merely reverses the sense of each individual change.

If successful, a pointer to a buffer containing the inverted changeset is stored in *ppOut, the size of the same buffer is stored in *pnOut, and SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are zeroed and an SQLite e