The TPF consumes table data using the fetch_into or fetch_block row block structures.
Each successful call to either fetch_into or fetch_block populates a a_v4_extfn_row_block structure.
The column_data members are:
Member | Description |
---|---|
null_value | The value representing NULL |
null_mask | One or more bits used to represent the NULL value |
data | Pointer to the data for the column. Depending on the type of fetch mechanism, either points to an address in the consumer, or an address where the data is stored in the UDF. |
piece_len | The actual length of data for variable-length data types |
blob | A non-NULL value means that the data for this column must be read using the blob API |