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