Dynamic SQL: BEGIN DECLARE...

HabaHaba · #1 (**permalink**) 11-12-03, 04:05

Hi all!
I have a small program which executes incoming queries and sends result back to client.
It's written on C with embeded SQL (SQLCI).
So, the problem is, that the incoming queries has a different size and i don't know how to dynamicly change it in:

Code:

    EXEC SQL BEGIN DECLARE SECTION;
        char hostvarquery[1024];
    EXEC SQL END DECLARE SECTION;

The question is -- How to put the variable in the string between BEGIN and END DECLARE SECTION?
Great thanks for answers!

sathyaram_s · #2 (**permalink**) 11-12-03, 04:41

You will have to read about SQLDA and use it in your program

HTH

sathyaram

Quote:

Originally posted by HabaHaba
Hi all!
I have a small program which executes incoming queries and sends result back to client.
It's written on C with embeded SQL (SQLCI).
So, the problem is, that the incoming queries has a different size and i don't know how to dynamicly change it in:

Code:

    EXEC SQL BEGIN DECLARE SECTION;
        char hostvarquery[1024];
    EXEC SQL END DECLARE SECTION;

The question is -- How to put the variable in the string between BEGIN and END DECLARE SECTION?
Great thanks for answers!

HabaHaba · #3 (**permalink**) 11-12-03, 06:57

Hello once again...
I'm using SQLDA, but, as i understand, it's useful after the query executed, but my problem, is that incoming query can be more than memory allocated for it. I know the size of query, but i can't dynamicly allocate memory for it when i'm declaring a host variable because when i'm trying to put the variable with known size in declaration, SQL precompiler fails with the message: "Variable hostvarquery not defined or not usable"
Here is a small part of my programm (to illustrate what i'm talking about):

Code:

    //bytes -- incoming variable
    EXEC SQL BEGIN DECLARE SECTION;
        char hostvarquery[bytes];
    EXEC SQL END DECLARE SECTION;   
    //myquery is a pointer to incoming query
    strcpy(hostvarquery,myquery);       
   //Here is a problem string
    EXEC SQL PREPARE MyStatement from :hostvarquery;
   //*mydaptr is a pointer to SQLDA struct
    EXEC SQL DESCRIBE MyStatement INTO :*mydaptr;

If declare hostvarquery like this:

Code:

    EXEC SQL BEGIN DECLARE SECTION;
        char hostvarquery[1024];
    EXEC SQL END DECLARE SECTION;

all will be fine, but hostvarquery will not be dynamic, and if a client sends query bigger than 1024 - it will not work

My question is how to make the size of hostvarquery dynamic?
Thanx one more time!

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