Table Functions (a_v4_extfn_table_func)

The consumer uses the a_v4_extfn_table_func structure to retrieve results from the producer.

Implementation

typedef struct a_v4_extfn_table_func {
//    size_t struct_size;

    /*  Open a result set. The UDF can allocate any resources needed for the result set.
    */
    short (UDF_CALLBACK *_open_extfn)(a_v4_extfn_table_context *);

    /*  Fetch rows into a provided row block. The UDF should implement this method if it does
        not have a preferred layout for its transfer area.
    */
    short (UDF_CALLBACK *_fetch_into_extfn)(a_v4_extfn_table_context *, a_v4_extfn_row_block 

*row_block);

    /*  Fetch a block that is allocated and configured by the UDF. The UDF should implement this
        method if it has a preferred layout of the transfer area.
    */
    short (UDF_CALLBACK *_fetch_block_extfn)(a_v4_extfn_table_context *, a_v4_extfn_row_block 

**row_block);

    /*  Restart a result set at the beginning of the table. This is an optional entry point.
    */
    short (UDF_CALLBACK *_rewind_extfn)(a_v4_extfn_table_context *);

    /*  Close a result set. The UDF can release any resources allocated for the result set.
    */
    short (UDF_CALLBACK *_close_extfn)(a_v4_extfn_table_context *);

    /* The following fields are reserved for future use and must be initialized to NULL. */
    void *_reserved1_must_be_null;
    void *_reserved2_must_be_null;

} a_v4_extfn_table_func;

Method Summary

Method Data Type Description
_open_extfn void Called by the server to initiate row fetching by opening a result set. The UDF can allocate any resources needed for the result set.
_fetch_into_extfn short Fetch rows into a provided row block. The UDF implements this method, if it does not have a preferred layout for its transfer area.
_fetch_block_extfn short Fetch a block that is allocated and configured by the UDF. The UDF implements this method, if it has a preferred layout of the transfer area.
_rewind_extfn void Optional function called by the server to restart the fetching from the beginning of the table.
_close_extfn void Called by the server to terminate row fetching by closing the result set. The UDF can release any resources allocated for the result set.
_reserved1_must_be_null void Reserved for future use. Must be initialized to NULL.
_reserved1_must_be_null void Reserved for future use. Must be initialized to NULL.

Description

The a_v4_extfn_table_func structure defines the methods used to fetch results from a table.

Parent topic: API Reference for a_v4_extfn