January 1993 Newsletter

Volume 3, No. 1

Highlights of This Issue

INFINITE ARRAY DISPLAY IN INFORMIX 4GL by SAMEER GUPTA

Next Meeting

Our next meeting is scheduled for Wednesday, February 17, 1993 from 9:30 to 11:30 am. We have a exciting presentation for the meeting from Four Seasons Software.

MEETING LOCATION: Informix Software

2111 Wilson Blvd., Suite 500

Arlington, VA

TOPICS Presentation - SuperNOVA from Four Seasons Software

Question and answer session.

Discussion - Future Plans for the User Group

SuperNOVA is a object-oriented, database independent, distributed processing 4GL application development tool. It provides a highly productive, interactive development environment which can eliminate traditional programming and is portable across multiple platforms (UNIX, MS-DOS, VMS). Using SuperNOVA, users can develop character and GUI (MS-Windows, Motif and OpenLook) applications. SuperNOVA's unique application independent, table driven distributed processing architecture, supports a variety of network protocols (TCP/IP, X.25, and Starlan). SuperNOVA interfaces to Informix, Oracle, Sybase, Ingres, Teradata, HP-Allbase, EDA/SQL, C_ISAM, in-core memory files, and flat file databases.

PowerBuilder

At the December 9th Informix User Group meeting, Noblestar Systems Corporation demonstrated an employee information application using PowerBuilder. PowerBuilder is a graphical user interface ("GUI") development tool which Noblestar and other firms have successfully used in the client-server arena. This product has recently been updated with an Informix interface, allowing rapid development of user-friendly GUI front-ends utilizing the Informix database.

For demonstration purposes, Noblestar is currently using the product with a number of stand-alone databases, including Informix server for DOS 4.0, Gupta, and SQL*Server. Among the many benefits to using a GUI tool such as PowerBuilder, is the ability to take advantage of the benefits of client-server architecture, and relational databases such as Informix.

Noblestar has been operating as a beta test site for the Informix version of PowerBuilder and is currently an authorized PowerBuilder trainer. If you would like more information on the uses of GUI technology in a client-server environment, and whether the incorporation of PowerBuilder would be advantageous to your applications development efforts, please contact Tim Bergloff at Noblestar's Falls Church, VA headquarters at (703) 641-8511.

Acknowledgement to Management Information Consulting, Inc.

Management Information Consulting, Inc has paid for the cost of copying and mailing our newsletter for the last two years. MIC has maintained our mailing lists and put in a lot of time and effort into getting the Informix User Group started. I would like to thank Cathy Begley, and MIC for all the work they have done to support the user group. MIC will be unable to continue handling our mailing list and we have appreciated their support.

Future of the Informix User Group

There are several issues we need to discuss at the next users group meeting.

We need a new sponsor for the mailings of the Newsletter.

We need to find ways to increase the participation in our user group. I was hoping to see more people attend this last meeting. The Informix User Group needs you support and participation to continue to operate and grow.

We need input from Informix users (you) on program ideas. What would you like to see at the meetings? What do you find helpful?

Attached is a user survey. Please fill it out and send it in. At the next meeting we will have a brainstorm of ideas and activities for the group.

INFINITE ARRAY DISPLAY IN INFORMIX 4GL

TATA CONSULTANCY SERVICES

C/O Sheet Metal Workers Int'l Association

1750 New York Avenue NW

Washington DC 20006

I think the infinite array problem is more severe when a user wants to DISPLAY/ ALTER records rather than when he wants to INPUT them as he user will always know as to how many are to be input. He however will not be aware as to how many records might be retrieved by the select statement.

The following program, display.4gl is a 4GL code to display infinite number of records in multiple row format on the screen. The code fetches ahead so that the time delay to retrieve the records is not very apparent. The user can use the UP, DOWN, F3, F4, PAGEUP and PAGEDOWN keys as in a normal display array statement. However, it always jumps a full page ahead. The user can use F7 key to exit. The code can be altered to make the display jump to a specified position (e.g. to a State Description starting with a certain character).

The code can be modified to modify and delete records by selecting the currently displayed row (identified by curdsp) and taking the necessary action.

Inserting infinite number of records can be achieved by physically inserting a specified number of records every time the limit is reached.

display.4gl
----------------------------------------------------------------------
-- Program for displaying infinite number of records
-- Developed by SAMEER GUPTA 01/07/1993
----------------------------------------------------------------------
DATABASE mds
GLOBALS
	DEFINE pcurr ARRAY[13] OF RECORD LIKE state_cm.*
# array to hold the current screen
	DEFINE pnext ARRAY[13] OF RECORD LIKE state_cm.*
# array to hold the next screen
	DEFINE pprev ARRAY[13] OF RECORD LIKE state_cm.*
# array to hold the previous screen
	DEFINE counter SMALLINT
	DEFINE maxcur SMALLINT
# number of records in the current array
	DEFINE maxprv SMALLINT
# number of records in the previous array
	DEFINE maxnxt SMALLINT
# number of records in the next array
	DEFINE maxcnt SMALLINT
# maximum number of records that can be displayed on the screen FIXED VALUE
	DEFINE pfirst SMALLINT
# pointer to the first record in the cursor
	DEFINE plast SMALLINT
# pointer to the last record in the cursor
	DEFINE curdsp SMALLINT
# current position on the screen
	DEFINE inpval CHAR(1)
# Key value being input
END GLOBALS

MAIN
OPEN FORM dsp100 FROM "dsp100"
DISPLAY FORM dsp100 
ATTRIBUTE (REVERSE, CYAN)
MESSAGE "Press F7 to Exit"
DECLARE c1 SCROLL CURSOR FOR 
	SELECT * 
	FROM state_cm
	ORDER BY state_desc
LET maxcnt = 13
OPEN c1
------------------------------------------------------------------
-- Initialize the previous array
------------------------------------------------------------------
INITIALIZE pprev TO NULL
LET maxprv = 0
------------------------------------------------------------------
-- Build the current array
------------------------------------------------------------------
FETCH FIRST c1 INTO pcurr[1].*
LET pfirst = 1
LET plast = 1
FOR counter = 2 TO maxcnt
	FETCH NEXT c1 INTO pcurr[counter].*
	IF STATUS = NOTFOUND THEN
		EXIT FOR
	END IF
	LET plast = plast + 1
END FOR
LET counter = counter - 1
LET maxcur = counter
IF maxcur = maxcnt THEN
------------------------------------------------------------------
-- Build the next array
------------------------------------------------------------------
	LET plast = plast + 1
	LET counter = 1
	FETCH ABSOLUTE plast c1 INTO pnext[1].*
	IF STATUS = NOTFOUND THEN
		LET plast = plast - 1
	ELSE
		FOR counter = 2 TO maxcnt
			FETCH NEXT c1 INTO pnext[counter].*
			IF STATUS = NOTFOUND THEN
				EXIT FOR
			END IF
			LET plast = plast + 1
		END FOR
	END IF
	LET counter = counter - 1
	LET maxnxt = counter
END IF
------------------------------------------------------------------
-- Display the first array
------------------------------------------------------------------
LET curdsp = 1
CALL dispcurr()
INPUT inpval FROM inpval
	ATTRIBUTE (REVERSE, CYAN, INVISIBLE)
	ON KEY(F3, NEXTPAGE)
		IF maxnxt = 0 THEN
			ERROR "END OF ARRAY"
		ELSE
			CALL fetchnext()
		END IF
	ON KEY(F4, PREVPAGE)
		IF maxprv = 0 THEN
			ERROR "START OF ARRAY"
		ELSE
			CALL fetchprev()
		END IF
	ON KEY(F7)
		EXIT INPUT
	ON KEY(DOWN)
          IF curdsp < maxcnt THEN
		DISPLAY pcurr[curdsp].* TO dsp100[curdsp].*
		ATTRIBUTE (REVERSE, WHITE)
		LET curdsp = curdsp + 1
		IF curdsp <= maxcur THEN
			DISPLAY pcurr[curdsp].* TO dsp100[curdsp].*
			ATTRIBUTE (REVERSE, RED)
		ELSE
			LET curdsp = curdsp - 1
			DISPLAY pcurr[curdsp].* TO dsp100[curdsp].*
			ATTRIBUTE (REVERSE, RED)
			ERROR "END OF ARRAY"
		END IF
	  ELSE
		CALL fetchnext()
	  END IF
	ON KEY(UP)
          IF curdsp > 1 THEN
		DISPLAY pcurr[curdsp].* TO dsp100[curdsp].*
		ATTRIBUTE (REVERSE, WHITE)
		LET curdsp = curdsp - 1
		DISPLAY pcurr[curdsp].* TO dsp100[curdsp].*
		ATTRIBUTE (REVERSE, RED)
          ELSE
		IF maxprv = 0 THEN
			ERROR "START OF ARRAY"
		ELSE
			CALL fetchprev()
		END IF
	  END IF
	AFTER FIELD inpval
		NEXT FIELD inpval
END INPUT
END MAIN

FUNCTION fetchnext()
	INITIALIZE pprev TO NULL
	FOR counter = 1 TO maxcnt
		LET pprev[counter].state_cd   = pcurr[counter].state_cd
		LET pprev[counter].state_desc = pcurr[counter].state_desc
	END FOR
	INITIALIZE pcurr TO NULL
	FOR counter = 1 TO maxnxt
		LET pcurr[counter].state_cd   = pnext[counter].state_cd
		LET pcurr[counter].state_desc = pnext[counter].state_desc
	END FOR
	LET pfirst = pfirst + maxprv
	LET maxprv = maxcnt
	LET maxcur = maxnxt
	LET curdsp = 1
	CALL dispcurr()
	LET plast = plast + 1
	INITIALIZE pnext TO NULL
	LET counter = 1
	FETCH ABSOLUTE plast c1 INTO pnext[1].*
	IF STATUS = NOTFOUND THEN
		LET plast = plast - 1
	ELSE
		FOR counter = 2 TO maxcnt
			FETCH NEXT c1 INTO pnext[counter].*
			IF STATUS = NOTFOUND THEN
				EXIT FOR
			END IF
			LET plast = plast + 1
		END FOR
	END IF
	LET counter = counter - 1
	LET maxnxt = counter
END FUNCTION

FUNCTION fetchprev()
	INITIALIZE pnext TO NULL
	FOR counter = 1 TO maxcur
		LET pnext[counter].state_cd   = pcurr[counter].state_cd
		LET pnext[counter].state_desc = pcurr[counter].state_desc
	END FOR
	FOR counter = 1 TO maxcnt
		LET pcurr[counter].state_cd   = pprev[counter].state_cd
		LET pcurr[counter].state_desc = pprev[counter].state_desc
	END FOR
	LET plast = plast - maxnxt
	LET maxnxt = maxcur
	LET maxcur = maxcnt
	LET curdsp = maxcnt
	CALL dispcurr()
	INITIALIZE pprev TO NULL
	IF pfirst = 1 THEN
		LET maxprv = 0
	ELSE
		LET pfirst = pfirst - 1
		FETCH ABSOLUTE pfirst c1 INTO pprev[maxcnt].*
		FOR counter = (maxcnt-1) TO 1 STEP -1
			FETCH PREVIOUS c1 INTO pprev[counter].*
		END FOR
		LET pfirst = pfirst - maxcnt + 1
		LET maxprv = maxcnt
	END IF
END FUNCTION

FUNCTION dispcurr()
	FOR counter = 1 TO maxcnt
		DISPLAY pcurr[counter].* TO dsp100[counter].*
		ATTRIBUTE (REVERSE, WHITE)
	END FOR
	DISPLAY pcurr[curdsp].* TO dsp100[curdsp].*
	ATTRIBUTE (REVERSE, RED)
END FUNCTION




state_cm.sql

create table state_cm 
  (
    state_cd char(2) not null,
    state_desc char(20) not null
  );
create index i01_state_cm on state_cm (state_cd);
create index ix111_2 on state_cm (state_desc);




display.per

DATABASE mds
SCREEN SIZE 24 BY 80
{
\gp------------------------------------------------------------------------------q\g
\g|\g                            Display State Codes                        DSP100
\g|\g
\g|------------------------------------------------------------------------------|\g
\g|\g                  Code     Description                                       
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g                  [f1]    [f2                            ]                   
\g|\g
\g|\g [a]              [f1]    [f2                            ]                   
\g|\g
\g|------------------------------------------------------------------------------|\g
\g|\g                                                                             
\g|\g
\gb------------------------------------------------------------------------------d\g
}
TABLES
state_cm
ATTRIBUTES
a  = FORMONLY.inpval TYPE CHAR, AUTONEXT;
f1 = state_cm.state_cd, AUTONEXT, UPSHIFT, COMMENTS = 'Enter the State Code.';
f2 = state_cm.state_desc, AUTONEXT, COMMENTS = 'Enter the State Description.';
END
INSTRUCTIONS
SCREEN RECORD dsp100[13] (state_cd, state_desc)
DELIMITERS " "
END