Application of descriptor in dynamic SQL

Dynamic

Application of descriptor in
dynamic SQL





Wang Guanghong




The flexibility of
dynamic SQL is well known, and I am here to introduce a dynamic SQL that applies descriptor:





$short B_num;


$char *command;





$char sql[1024];


$short Flag;


$date date;


$long number, B_count, J;


$long Prec;


$long type;


$long Scale;


$double money;








sprintf (SQL, "SELECT * from table");





$prepare qid from $Sql;


if (SQLCODE) return-1;


$declare BROWSE scroll cursor for qid;


if (SQLCODE) return-2;


$allocate descriptor ' browsdesc ' with max:b_num; Allocate space in the description area and set the maximum number of items








$get Descriptor ' browsdesc ': b_count=count;//get the number of fields to query


if (SQLCODE) {


Sqlerrhandle (SQLCODE, SELECT);


Goto EXIT0;


  }





$fetch BROWSE Using SQL descriptor ' BROWSDESC ';


if (SQLCODE) {


strcpy (Retpacket.data, "select error|");


Sqlerrhandle (SQLCODE, SELECT);


Goto EXIT0;


  }





for (j=1;j<=b_count;j++) {


$get Descriptor ' browsdesc ' value $j//Current field serial number


$prec =precision,/*money, decimal*/


$scale =scale,/*money, decimal*/


$type =type;


if (SQLCODE) {


Sqlerrhandle (SQLCODE, SELECT);


Goto EXIT0;


   }


switch (type) {


Case Sqlfloat:


Case Sqlsmfloat:


Case SqlDecimal:


Case SqlMoney:


if (PREC)


sprintf (FMT, "%s%d.%df\0", "%", prec+1, scale);


Else


strcpy (FMT, "%f");


$get Descriptor ' browsdesc ' value $j


$money =data;


sprintf (result, FMT, money);





if (sqlcode==dataisnull) result[0]=0;


break;


Default:


$get Descriptor ' browsdesc ' value $j


$result =data;


}//switch





if (sqlcode==dataisnull) sqlcode=0;





if (SQLCODE) {


Sqlerrhandle (SQLCODE, SELECT);


Goto EXIT0;


   }





output (result);//Outputs





}//for