HeapTuple SPI_modifytuple(Relation rel, HeapTuple row, int ncols, int * colnum, Datum * values, const char * nulls)
SPI_modifytuple creates a new row by substituting new values for selected columns, copying the original row's columns at other positions. The input row is not modified.
Used only as the source of the row descriptor for the row. (Passing a relation rather than a row descriptor is a misfeature.)
row to be modified
number of columns to be changed
an array of length ncols, containing the numbers of the columns that are to be changed (column numbers start at 1)
an array of length ncols, containing the new values for the specified columns
an array of length ncols, describing which new values are null
If nulls is NULL then
SPI_modifytuple assumes that no new values are null. Otherwise, each entry of the nulls array should be ' ' if the corresponding new value is non-null, or 'n' if the corresponding new value is null. (In the latter case, the actual value in the corresponding values entry doesn't matter.) Note that nulls is not a text string, just an array: it does not need a '\0' terminator.
new row with modifications, allocated in the upper executor context; NULL only if row is NULL
On error, SPI_result is set as follows:
if rel is NULL, or if row is NULL, or if ncols is less than or equal to 0, or if colnum is NULL, or if values is NULL.
if colnum contains an invalid column number (less than or equal to 0 or greater than the number of column in row)