Re: VMS x86-64 database server

On 7/6/2025 10:42 PM, Lawrence D'Oliveiro wrote:

On Sun, 6 Jul 2025 19:58:04 -0400, Arne Vajhøj wrote:

But in embedded SQL then it is the standard way to do queries.

 Not sure what “embedded SQL” means. I normally use SQL “embedded” in an
app written in some other programming language.

Embedded SQL is a thing or was a thing 30-40-50 years ago.
Basically you write source code with SQL statements prefixed
by EXEC SQL, put it through a pre-compiler to get valid
code in whatever language (Cobol, PL/I, C or whatever).
Here is C call API code:
     PGresult *res;
     res = PQprepare(con, "stmt_selectf1f2fromt1", "SELECT f1,f2 FROM t1", 0, NULL);
     PQclear(res);
     res = PQexecPrepared(con, "stmt_selectf1f2fromt1", 0, NULL, NULL, NULL, 0);
     int nrows = PQntuples(res);
     for(int i = 0; i < nrows; i++)
     {
         int f1 = atoi(PQgetvalue(res, i, 0));
         char f2[51];
         strcpy(f2, PQgetvalue(res, i, 1));
         printf("%d %s\n", f1, f2);
     }
     PQclear(res);
     PQexec(con, "DEALLOCATE stmt_selectf1f2fromt1");
same code as C with embedded SQL:
     EXEC SQL DECLARE mycursor CURSOR FOR SELECT f1,f2 FROM t1;
     EXEC SQL OPEN mycursor;
     for(;;)
     {
         EXEC SQL FETCH mycursor INTO :f1, :f2;
         if(sqlca.sqlcode != 0) break;
         printf("%d %s\n", f1, f2);
     }
     EXEC SQL CLOSE mycursor;
Simpler shorter code, because the pre-compiler handle
some of the plumbing.
Arne