C関数定義 - Advanced SQL Engine - Teradata Database

#define SQL_TEXT Latin_Text
#include <sqltypes_td.h>

typedef unsigned char byte;

// INSERT Level UDF
void InsertLevel( short int  *sess_level,
                  short int  *new_row )
{
   // Level of new row equals that of the session
   // return level to DBS
   *new_row = *sess_level;
   return;
}

// UPDATE Level UDF

void UpdateLevel( short int  *sess_level,
                  short int  *curr_row,
                  short int  *upd_row )
{
   // Session's level must be equal to or greater than row’s to allow
   // the update. If update is allowed, then the level of the updated
   // row is changed to that of the session.

   // can the session update the row?
   if (*sess_level >= *curr_row)
      // set level in updated row to session's level
      *upd_row = *sess_level;
   else
      // update is not allowed
      *upd_row = 0;
   return;
}

//DELETE Level UDF

void DeleteLevel( short int  *curr_row,
                  char       *result )
{
   // Row can only be deleted if it has a label of unclassified
   if (*curr_row == 1)
      // delete is allowed
      *result = 'T';
   else
      *result = 'F';
   return;
}

// SELECT Level UDF

void ReadLevel( short int  *sess_level,
                short int  *curr_row,
                char       *result )
{
   // Read allowed if session's level is equal to or greater than row's
   if (*sess_level >= *curr_row)
      // select is allowed
      *result = 'T';
   else
      //select is not allowed
      *result = 'F';
   return;
}

//INSERT Category UDF

void InsertCategory( byte sess_cat[],
                     byte new_row[],
                     int *indic1,
                     int *retindic)
{
   int i;

   // policy is that category for new row equals that for the session

   if (*indic1 == -1)  // null session, then null new row
      *retindic = -1;
   else  // non-null session, then new row equals session
   {
      *retindic = 0;
      for (i  =  0; i  <  8; i++)
         new_row[i] = sess_cat[i];
   }
   return;
}

// UPDATE Category UDF

void UpdateCategory( byte sess_cat[],
                     byte curr_row[],
                     byte new_row[],
                     int *indic1,
                     int *indic2,
                     int *retindic)

{

   int i;

   // Policy is that row can be updated if user's category is a
   // superset of the row's category. If the update is allowed,
   // then the category for the new row is a combination of the
   // categories of the current row plus those of the session.

   if (*indic1 == -1)  // if session’s category is null
   {
      if (*indic2 == -1) // if row’s category is null, update is allowed
      {  // both are null
         *retindic = -1;  // new row constraint is null
         return;
      }
      else
      {   // session is null and row is not, so disallow update
         *retindic = 0;
         for (i = 0; i < 8; i++)
            new_row[i] = 0;  // set return category to null for error
         return;
      }
   }
   // session’s category is not null
   *retindic = 0;  // must return a category
   if (*indic2 == -1)  // if row’s category is null, then update
                       // is allowed
      {
         for (i = 0; i < 8; i++)
            new_row[i] = sess_cat[i];  //set return category to session
         return;
      }
   // session’s category and input row’s category are not null
   for (i = 0; i < 8; i++)  // does session dominate row?
      if ((sess_cat[i] & curr_row[i]) != curr_row[i])
         // no it does not, so update is not allowed
         {
         for (i = 0; i < 8; i++)
            new_row[i] = 0;  // set return category to all zeroes
                              //for error
         return;
         }
   // update is allowed; set return category to a combination of
   // session’s and row’s categories
   for (i = 0; i < 8; i++)
      new_row[i] = sess_cat[i] | curr_row[i];  //inclusive or
   return;
}

// DELETE Category UDF

void DeleteCategory( byte curr_row[],
                     char *result,
                     int *indic1,
                     int *retindic)

{
   // Policy is that row can be deleted only if its category is null
   *retindic = 0;  // result is always not null
   if (*indic1 == -1)  // if row's category is not null
      *result = 'T';   // delete is allowed
   else
      *result = 'F';   // delete is not allowed
   return;
}

// SELECT Category UDF

void ReadCategory( byte sess_cat[],
                   byte curr_row[],
                   char *result,
                   int *indic1,
                   int *indic2,
                   int *retindic)

{
   int i;

   // Policy is that row can be selected if user's category is a
   // superset of the row's category.
   *retindic = 0; // result is always not null
   *result = 'T';
   if ((*indic1 == *indic2) && (*indic1 == -1)) // both are null
      return;  // allow select
   if (*indic2 == -1)  // row is null and session isn't
      return;  // allow select
   // both are not null
   *result = 'F';
   for (i = 0; i < 8; i++)  // does session dominate row
      // does session dominate
      if ((curr_row[i] ^ sess_cat[i]) & curr_row[i])
         return;  // no, so select is not allowed
   *result = 'T';  // yes, so allow select
   return;
}