HeapTuple SPI_modifytuple(Relation rel, HeapTuple row, ncols, 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 column numbers in the array colnum
array of the numbers of the columns that are to be changed (column numbers start at 1)
new values for the specified columns
which new values are null, if any (see SPI_execute_plan for the format)
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)
