# Get max ISN **URL:** \ **Category:** Forum\ **Tags:** Adabas-Natural, Natural, Natural-Code-Samples\ **Created:** [June 14, 2008, 10:54am UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319 "2008-06-14T10:54:59Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![noorieh](https://avatars.discourse-cdn.com/v4/letter/n/cdc98d/32.png) [@noorieh](https://techcommunity.softwareag.com/u/noorieh)\ **Post date:** [June 14, 2008, 10:54am UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/1 "2008-06-14T10:54:59Z")
Hello to all can you tell me how can i get max ISN (ISN of last record) of one adabas file? thanks ---
**Author:** ![Steve\_Robinson](https://sea1.discourse-cdn.com/techcommunity/user_avatar/techcommunity.softwareag.com/steve_robinson/32/107_2.png) [@Steve\_Robinson](https://techcommunity.softwareag.com/u/Steve_Robinson)\ **Post date:** [June 14, 2008, 4:49pm UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/2 "2008-06-14T16:49:32Z")
Unfortunately, there is not a READ IN DESCENDING ISN SEQUENCE. If this is a small file, and you were only going to do this once, you could: ``` READ file BY ISN IGNORE AT END OF DATA WRITE *ISN ``` You could improve on this by adding a STARTING FROM clause if you knew a value that was less than the max, but hopefully reasonably close to the end. Actually, this would work reasonably well for a large file as well, as long as you had available a reasonably close estimate of the highest ISN. If you had a file with non reusable ISNs, and if you had a date field you could ``` READ (1) IN DESCENDING SEQUENCE BY DATE ``` What do you need this ISN for? steve ---
**Author:** ![noorieh](https://avatars.discourse-cdn.com/v4/letter/n/cdc98d/32.png) [@noorieh](https://techcommunity.softwareag.com/u/noorieh)\ **Post date:** [June 15, 2008, 1:17pm UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/3 "2008-06-15T13:17:39Z")
Dear Steve Robinson Thanks for your message Sorry for my bad english I am using entirex. and have a sub program that return 10 record from one ISN (READ (10) MY\_VIEW STARTING WITH ISN=#I) I need to have max ISN for check this → if #I\>max ISN or not. if it is ok, return nothing and return error message. Thanks ---
**Author:** ![Bijan](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@Bijan](https://techcommunity.softwareag.com/u/Bijan)\ **Post date:** [June 15, 2008, 1:49pm UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/4 "2008-06-15T13:49:09Z")
It seems that you want to stop further request for data at EOF. How about checking number of records on the client side for \< 10? You may get a totally blank page if your data is multiple of 10. ---
**Author:** ![Matthias1](https://avatars.discourse-cdn.com/v4/letter/m/9fc348/32.png) [@Matthias1](https://techcommunity.softwareag.com/u/Matthias1)\ **Post date:** [June 16, 2008, 12:53pm UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/5 "2008-06-16T12:53:40Z")
We got a related discussion here: [http://tech.forums.softwareag.com/viewtopic.php?t=7099](http://tech.forums.softwareag.com/viewtopic.php?t=7099) ---
**Author:** ![system](https://global.discourse-cdn.com/techcommunity/original/3X/c/d/cd19967bb605d28a72d77eb83a1cae22f3df2eb8.svg) [@system](https://techcommunity.softwareag.com/u/system)\ **Post date:** [September 3, 2009, 11:09am UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/6 "2009-09-03T11:09:37Z")
Use this copycode: ZTOPISN: 0010 \* 0020 \* Works out the highest ISN for a file by PSM 7/12/07 0030 \* 0040 \* Use in conjunction with ZTOPISNL eg: 0050 \* 0060 \* DEFINE DATA LOCAL USING ZTOPISNL 0070 \* LOCAL 0080 \* 1 MY-VIEW VIEW OF MY-DDM 0090 \* … 0100 \* END-DEFINE 0110 \* INCLUDE ZTOPISN ‘MY-VIEW’ 0120 \* WRITE ‘TOP ISN=’ #TOPISN 0130 \* END 0140 \* 0150 \* 0160 #TOPISN := 9999999 0170 RESET #LAST-ISN #LAST-TOPISN 0180 T-RPT. REPEAT 0190 TOPISN. READ (1) &1& BY ISN = #TOPISN 0200 DECIDE FOR FIRST CONDITION 0210 WHEN #LAST-ISN = 0 0220 #TOPISN := #TOPISN \* 2 0230 WHEN #LAST-ISN = \*ISN(TOPISN.) 0240 #TOPISN := \*ISN(TOPISN.) 0250 ESCAPE BOTTOM (T-RPT.) 0260 WHEN #LAST-TOPISN NE 0 0270 #TOPISN := \*ISN(TOPISN.) + ((#LAST-TOPISN - \*ISN(TOPISN.)) / 2) 0280 WHEN NONE IGNORE 0290 END-DECIDE 0300 #LAST-ISN := \*ISN(TOPISN.) 0310 END-READ 0320 IF \*COUNTER(TOPISN.) = 0 THEN 0330 IF #LAST-ISN = 0 THEN 0340 #TOPISN := #TOPISN / 2 0350 ELSE 0360 #LAST-TOPISN := #TOPISN 0370 #TOPISN := #LAST-ISN + ((#TOPISN - #LAST-ISN) / 2) 0380 END-IF 0390 END-IF 0400 END-REPEAT and this LDA ZTOPISNL ``` -----------------Local ZTOPISNL ----Lib CORCODES ---- ``` 0010 1 #TOPISN (I4) 0020 1 #LAST-ISN (I4) 0030 1 #LAST-TOPISN (I4) This does a binary search to get the highest isn. ---
**Author:** ![Douglas\_Kelly](https://sea1.discourse-cdn.com/techcommunity/user_avatar/techcommunity.softwareag.com/douglas_kelly/32/102_2.png) [@Douglas\_Kelly](https://techcommunity.softwareag.com/u/Douglas_Kelly)\ **Post date:** [September 6, 2009, 11:35am UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/7 "2009-09-06T11:35:37Z")
> [@noorieh](#): > > I am using entirex. and have a sub program that return 10 record from one ISN (READ (10) MY\_VIEW STARTING WITH ISN=#I) > > I need to have max ISN for check this → if #I\>max ISN or not. > > if it is ok, return nothing and return error message. If you reach max isn for the file, you will exit from the READ loop if you are reading by ISN (the READ example you give is not clear/complete). If you are reading by a non-unique descriptor (hence the need for the STARTING WITH ISN clause), then knowing the max ISN is completely useless: if the record with the max ISN has the lowest descriptor value, it will be the first record you read. If you are reading by ISN, then when you start with an ISN \> max isn, your loop count (\*COUNTER) will be 0. If you are reading by a descriptor, starting from an ISN, you will get the next record greater than your starting ISN and descriptor value. Again, knowing the max isn will not be useful in this case. ---
**Author:** ![Angel\_Mendoza\_O1](https://sea1.discourse-cdn.com/techcommunity/user_avatar/techcommunity.softwareag.com/angel_mendoza_o1/32/191_2.png) [@Angel\_Mendoza\_O1](https://techcommunity.softwareag.com/u/Angel_Mendoza_O1)\ **Post date:** [February 20, 2010, 1:31am UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/8 "2010-02-20T01:31:35Z")
Using binary search… ```auto DEFINE DATA LOCAL 1 myView VIEW OF SAP_PACIENTE 1 #mas-alto (n10) 1 #inicio-isn (n10) 1 #fin-isn (n10) 1 #busca-isn (n10) 1 #FOUND (l) 1 #pos (n10) END-DEFINE RESET #mas-alto MOVE 1 TO #inicio-isn MOVE 999999999 TO #fin-isn * if #pos = 0 REPEAT UNTIL #mas-alto > 0 * #busca-isn := ((#fin-isn + #inicio-isn) / 2) RESET #FOUND r3. READ myView BY ISN FROM #busca-isn IF #FOUND /* More than one record #inicio-isn := *ISN(r3.) RESET #mas-alto ESCAPE BOTTOM end-if MOVE TRUE TO #FOUND MOVE *ISN TO #mas-alto * end-read IF NOT #FOUND #fin-isn := #busca-isn end-if end-repeat #pos := #mas-alto else #pos := -1 end-if write 'max isn : ' #pos end ``` ---
**Author:** ![system](https://global.discourse-cdn.com/techcommunity/original/3X/c/d/cd19967bb605d28a72d77eb83a1cae22f3df2eb8.svg) [@system](https://techcommunity.softwareag.com/u/system)\ **Post date:** [April 2, 2021, 2:50pm UTC](https://techcommunity.softwareag.com/t/get-max-isn/78319/9 "2021-04-02T14:50:30Z")