From: Anton de Wet <adw@obsidian.co.za>
Date: Mon, 18 Mar 1996 10:14:53 +0200 (GMT+0200)
Subject: Re: [PG95]: Assigning to arrays with libpgtcl

On Sat, 16 Mar 1996, Jesus Chrysler wrote:

> I found that when I assign a result of a pg_exec to an array, I get odd 
> results:
> 
> (by the way, dragnet is a tcl/tclx/pgtcl shell I made)
> 
> dragnet>set result [pg_exec $db "SELECT * FROM account_info WHERE login = 
> 'jchryslr'"]

> dragnet>pg_result $result -assign Row(user)
> Row(user)
> dragnet>array names Row
> dragnet>array names Row(user)
> 0,name 0,address 0,telephone

> so.... I'm thinking that when an array is given as the argument, it should be
> added to the array, so that in this case the variable Row(user,0,name) should
> have been created?

I've had a similar problem. All my tables have a unique (enforced by 
external programs) field called idnr. I wanted to be able to assign the 
result to a array and use the first field returned (idnr in my case) to 
be used as the first index of the array.

I've made a quick hack to pgtclCmds.c to add an option to pg_result 
(which I called -assignbyidx) to do this.

To use it, (for example) 
dragnet> set result [pg_exec $db "SELECT user, passwd, shell FROM 
         account_info WHERE login ='myname']
 
dragnet> pg_result $result -assignbyidx Row

And you should have 
dragnet> array names Row
user,passwd user,shell

Hope this helps

Anton


Here is the patch: (to pgtclCmds.c)
- -------------------------------Cut-here----------------------------------------

197,198d196
<  -assignbyidx arrayName
<  assign the results to an array using the first field as a key
216d213
<     char prearrayInd[MAX_MESSAGE_LEN];
274,294d270
<     else if (strcmp(opt, "-assignbyidx") == 0) {
< 	if (argc != 4) {
< 	    Tcl_AppendResult(interp, "-assignbyidx option must be followed by a variable name",0);
< 	    return TCL_ERROR;
< 	}
< 	arrVar = argv[3];
< 	/* this assignment assigns the table of result tuples into a giant
< 	   array with the name given in the argument,
< 	   the indices of the array or (tupno,attrName)*/
< 	for (tupno = 0; tupno<PQntuples(result); tupno++) {
< 	    sprintf(prearrayInd,"%s",PQgetvalue(result,tupno,0));
< 	    for (i=1;i<PQnfields(result);i++) {
< 		sprintf(arrayInd, "%s,%s", prearrayInd, PQfname(result,i));
< 		Tcl_SetVar2(interp, arrVar, arrayInd, 
< 			    PQgetvalue(result,tupno,i),
< 			    TCL_LEAVE_ERR_MSG);
< 	    }
< 	}
< 	Tcl_AppendResult(interp, arrVar, 0);
< 	return TCL_OK;
<     }
334d309
< 		     "\t-assignbyidx arrayVarName\n",

- -------------------------------Cut-here-----------------------------------------