HI,

HOW DO I USE BTREE IN UNIDATA?

VERSION :

UniData RDBMS............ 7.1
Connection Pooling....... 7.1
NFA...................... 7.1
RFS...................... 7.1
Device License........... 7.1
EDA...................... 7.1
The current account is version 3.3.2i.b2.

Please be more specific about your need. Are you talking about B-trees
in general or accessing alternate key indices (which use an internal B-
tree structure)?


Martin Phillips, Ladybridge Systems Ltd

Martin's right - we need a little more info.

However, if you're talking about alternate key indices you can try
starting with:

HELP UPDATEVOC
HELP CREATE.INDEX

The previous commands are entered at the ECL ":" prompt.
Then look at Chapter 6 in the Using Unidata Manual. You can find it at:
<http://www-306.ibm.com/software/data/u2/pubs/library/71unidata/>

hth
Colin Alfke
Calgary Canada


Martin Phillips wrote:

:CREATE-INDEX MYFILE DICTNAME (you can tell I'm from PICK)
:BUILD-INDEX MYFILE

Then in BASIC you'd...

NAME.KEY = PREF.KEY ; ** the name to start searching
TOP.NAME = NULL$ ; ** the top name in the search
END.NAME = NULL$ ; ** the bottom name in the search
*
** read file for UD indexes
OPEN FNAME TO ROOT.ID ELSE
CRT EMSG:A.CODE:MSG1:
WKAMT = NULL$
GOTO END.OF.PROGRAM
END
*
** find first & last name in tree
topKEY.ID = NULL$
botKEY.ID = NULL$
*
** set top and bottom start placemarks
TOP.START = PREF.KEY:ICONV('00', 'MX0C') ; ** UD version
END.START = PREF.KEY:ICONV('7B', 'MX0C') ; ** UD version
*
** initialize the top and bottom names
TOP.NAME = TOP.START
END.NAME = END.START
*
** get top and bottom name in tree. do the bottom name first as
** the 1st name's index is left for further processing.
SETINDEX A.CODE, END.NAME ON ROOT.ID
READXBCK END.NAME FROM ROOT.ID ELSE NULL
botKEY.ID = @ID
SETINDEX A.CODE, TOP.NAME ON ROOT.ID
READXFWD TOP.NAME FROM ROOT.ID ELSE NULL
topKEY.ID = @ID
*
** validate key
BEGIN CASE
CASE topKEY.ID = NULL$ AND botKEY.ID = NULL$
GOTO PROGRAM.COMPLETE
CASE TOP.NAME[1,PREF.LEN] NE PREF.KEY
GOTO PROGRAM.COMPLETE
CASE TOP.NAME = PREF.KEY
GOTO PROGRAM.COMPLETE
END CASE

Now you would use the READFWD and READBCK keywords to traverse the index.

Hope this helps.

Bill

"alegon" <alegon (AT) bol (DOT) com.br> wrote

On 7 jun, 02:38, "Bill H" <some... (AT) somedomain (DOT) com> wrote:
thank you very much