topic Re: Update destination table only if any values changes in the source columns (not using CDC) in Talend Studio

Update destination table only if any values changes in the source columns (not using CDC)

Anonymous — Sat, 21 Mar 2020 20:15:42 GMT

Experts,

I am using TOS DI and would like to achieve the below use case.

Source:table1

ID,Flag

1,A

2,B

Run1:

Destination:table1_stg

1,A

2,E

Run2: (no change for existing records but one new record is new)

ID,Flag

1,A

2,E

3,E

(**** as per the current job flow, tDBInput->tMap->(1)tDBOutput(insertflow) -> (2)tDBOutput(updateflow). actually the new records goes in insert flow at the same time there old 2 records also goes in updateflow but there is no change)

Run3: (no change for existing records but one new record is new)

ID,Flag

1,E

2,E

3,E

(**** this time all three goes in update flow, yes this is ok)

But Run2 how to stop going the updateflow if there is no change in the source data?

Re: Update destination table only if any values changes in the source columns (not using CDC)

manodwhb — Sun, 22 Mar 2020 06:59:53 GMT

You need to certain two separate flows ,one for new and another one for to update the using one tmap in tmap you need to specify the exact change like I'd from look-up table is not null and flag not equals from look-up you need to enable the expression section.

Re: Update destination table only if any values changes in the source columns (not using CDC)

Anonymous — Sun, 22 Mar 2020 08:21:03 GMT

Dear Mano,

thank your info, i have tried the same... the issue is even there is no change in the source data the update flow is updating all the records.

Re: Update destination table only if any values changes in the source columns (not using CDC)

manodwhb — Mon, 23 Mar 2020 03:17:05 GMT

Then,I believe you have not written enable or disable expression,what expression you have used.

Re: Update destination table only if any values changes in the source columns (not using CDC)

Anonymous — Mon, 23 Mar 2020 06:48:34 GMT

Dear Mano,

Actually i want to achieve what CDC does. can you pls let me the expression i should put based on my source data in my question thread.

Re: Update destination table only if any values changes in the source columns (not using CDC)

manodwhb — Mon, 23 Mar 2020 12:37:38 GMT

You need to implement for all CDC logic's like new, update and delete? For new and update create one flow and for delete create separate flow. To update you do look up on key and then you mention the expression for the update output in Tampa like row2.key is not null and row1.column1 not equals to row2.column1. here row1 is main and row2 is look-up.

Re: Update destination table only if any values changes in the source columns (not using CDC)

raowaqasakram — Thu, 21 Jul 2022 14:15:28 GMT

But where to set that if the conditions are true then only put the UPDATE operation?

@sen kum

@Manohar B

Re: Update destination table only if any values changes in the source columns (not using CDC)

manodwhb — Thu, 21 Jul 2022 14:46:27 GMT

@Rao Waqas Akram , you need to check the if condition in tmap output section, enable/disable filter section.

Re: Update destination table only if any values changes in the source columns (not using CDC)

raowaqasakram — Thu, 21 Jul 2022 17:22:08 GMT

thanks alot @Manohar B