Obtain old.* Values From A Changeset Iterator

int sqlite3changeset_old(
  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
  int iVal,                       /* Column number */
  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
);

The pIter argument passed to this function may either be an iterator passed to a conflict-handler by sqlite3changeset_apply(), or an iterator created by sqlite3changeset_start(). In the latter case, the most recent call to sqlite3changeset_next() must have returned SQLITE_ROW. Furthermore, it may only be called if the type of change that the iterator currently points to is either SQLITE_DELETE or SQLITE_UPDATE. Otherwise, this function returns SQLITE_MISUSE and sets *ppValue to NULL.

Argument iVal must be greater than or equal to 0, and less than the number of columns in the table affected by the current change. Otherwise, SQLITE_RANGE is returned and *ppValue is set to NULL.

If successful, this function sets *ppValue to point to a protected sqlite3_value object containing the iVal'th value from the vector of original row values stored as part of the UPDATE or DELETE change and returns SQLITE_OK. The name of the function comes from the fact that this is similar to the "old.*" columns available to update or delete triggers.

If some other error occurs (e.g. an OOM condition), an SQLite error code is returned and *ppValue is set to NULL.

See also lists of Objects, Constants, and Functions.