SQLite

**         being opened for read/write access)^.
** </ul>
**
** ^Unless it returns SQLITE_MISUSE, this function sets the 
** [database connection] error code and message accessible via 
** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 
**
** A BLOB referenced by sqlite3_blob_open() and be read using the
** [sqlite3_blob_read()] interface and modified by using
** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
** different row of the same table using the [sqlite3_blob_reopen()]
** interface.  However, the column, table, or database of a [BLOB handle]
** cannot be changed once after the [BLOB handle] is opened.
**
** ^(If the row that a BLOB handle points to is modified by an
** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
** then the BLOB handle is marked as "expired".
** This is true if any column of the row is changed, even a column
** other than the one the BLOB handle is open on.)^
** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for

**
** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
** and the built-in [zeroblob] SQL function may be used to create a 
** zero-filled blob to read or write using the incremental-blob interface.
**
** To avoid a resource leak, every open [BLOB handle] should eventually
** be released by a call to [sqlite3_blob_close()].
**
** See also: [sqlite3_blob_close()],
** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
*/
int sqlite3_blob_open(
  sqlite3*,
  const char *zDb,
  const char *zTable,
  const char *zColumn,
  sqlite3_int64 iRow,
  int flags,
  sqlite3_blob **ppBlob
);

/*
** CAPI3REF: Move a BLOB Handle to a New Row
** METHOD: sqlite3_blob
**
** ^This function is used to move an existing [BLOB handle] so that it points
** to a different row of the same database table. ^The new row is identified
** by the rowid value passed as the second argument. Only the row can be
** changed. ^The database, table and column on which the blob handle is open
** remain the same. Moving an existing [BLOB handle] to a new row is
** faster than closing the existing handle and opening a new one.
**
** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
** it must exist and there must be either a blob or text value stored in
** the nominated column.)^ ^If the new row is not present in the table, or if
** it does not contain a blob or text value, or if another error occurs, an
** SQLite error code is returned and the blob handle is considered aborted.