Oid SPI_gettypeid(TupleDesc rowdesc , int colnumber )
SPI_gettypeid returns the OID of the data type of the specified column.
SPI_gettypeid
input row description
column number (count starts at 1)
The OID of the data type of the specified column or InvalidOid on error. On error, SPI_result is set to SPI_ERROR_NOATTRIBUTE .