SQLITE3CHANGESET_INVERT(3)

SQLITE3CHANGESET_INVERT(3) | Library Functions Manual | SQLITE3CHANGESET_INVERT(3)

# NAME

`sqlite3changeset_invert` —
Invert A Changeset

# SYNOPSIS

int
`sqlite3changeset_invert`(int nIn, const void *pIn, int *pnOut, void **ppOut );

# DESCRIPTION

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 error code returned.

It is the responsibility of the caller to eventually call sqlite3_free() on the *ppOut pointer to free the buffer allocation following a successful call to this function.

WARNING/TODO: This function currently assumes that the input is a valid changeset. If it is not, the results are undefined.

December 19, 2018 | NetBSD 9.3