Register the statcollect() function

The registration of this function has the following requirements:

• You must name this user-defined function statcollect.

  The database server handles routine resolution based on the data type of the first argument to statcollect(). If the name of your C statistics-collection function is not statcollect(), specify the C function name in the EXTERNAL NAME clause.

• You must declare the statcollect() function with HANDLESNULLS routine modifier.

  Your statistics-collection function can choose whether to include the NULL value in the statistics data that it generates.

• The data types of the parameters must be as follows.

  Parameter number	Parameter data type
  1	SQL name for the user-defined data type
  2	FLOAT
  3	FLOAT Do not include the declaration of the MI_FPARAM structure in the SQL registration. The function must return a value of type stat.

The following CREATE FUNCTION statement registers the statistics-collection function that Sample declaration of a statistics-collection function declares:

CREATE FUNCTION statcollect(ll_arg longlong, num_rows FLOAT,
   resolution FLOAT)
RETURNING stat
WITH (HANDLESNULLS)
EXTERNAL NAME '/usr/udrs/bin/longlong.so(stat_collect_ll)'
LANGUAGE C;