topic Re: tMemorizeRow only filling blank data once in Talend Studio

tMemorizeRow only filling blank data once

jeanjpotgieter — Mon, 29 Jun 2026 13:14:06 GMT

Good morning,

I have a use case where I need to pull a description field down from a previous row if the IDs match:

ID | Description|

100|Apple|
100||
100||
100||
101|Banana
102||
103|Kiwi|

should end up like this:
100|Apple|
100|Apple|
100|Apple|
100|Apple|
101|Banana
102||
103|Kiwi

I'm using the tMemorize row component. I have 2 rows memorized and I have the ID and Description checked on the tMemorize_Row component.

In my tMap I have logic that says: Relational.ISNULL(row1.Description) && row1.ID.equals(ID_rMemorizeRows_1[1]) ? Description.tMemorizeRows_1[1]
:row1.Description

It works fine for pulling in the first blank, but then pulls in nothing after that, so I'm getting:
100|Apple|
100|Apple|
100||
100||
...

How do I get it to pull down blank descriptions an unspecified amount of times?

Re: tMemorizeRow only filling blank data once

DaniZ — Mon, 29 Jun 2026 15:52:40 GMT

Hi,

If you are constantly memorizing the incoming rows, then from the 3rd row it will memorize a null description. It keeps memorizing the 2 LAST rows that were moved through main, and doesn't work retroactively, so it correctly remembers the empty description in the previous row once it get to the 3rd row.

To get what you want you would need to store the value you want to remember in a context or use the Var section of the tMap to create a retrospective lookup. tMemorizeRow is not really required here, though you could use it to reference the previous ID instead of using a code check if the ID changed.

Re: tMemorizeRow only filling blank data once

jeanjpotgieter — Tue, 07 Jul 2026 06:23:23 GMT

Thanks for the reply but I wasn't able to solve the issue so I must be doing something wrong.

I have a tFileInputExcel feeding into the tMap. I've created two variables and defined them as:

prevDesc [!Relational.ISNULL(Var.currentDesc) && Var.currentDesc.length() > 0 ? Var.currentDesc :""]
currentDesc [row1.Description]

Then in my output column I have Description defined as:

[Var.currentDesc.length() > 0 ? Var.currentDesc :Var.prevDesc]

I expected that the prevDesc would hold the value of Var.currentDesc because it hasn't been set for the current row yet but it's doing the same thing that the tMemorizeRows did, only copying down a blank value once. Am I doing the retrospective lookup incorrectly?

Re: tMemorizeRow only filling blank data once

DaniZ — Tue, 07 Jul 2026 08:06:56 GMT

You need something like this in the tMap var section:

PrevDesc --> row9.Description == null ? Var.prevdesc : row9.Description

PrevID --> Var.prevID == null ? row9.ID : Var.prevID

CurrentDesc --> row9.Description == null && row9.ID.equals(Var.prevID) ? Var.prevdesc : row9.Description

Re: tMemorizeRow only filling blank data once

jeanjpotgieter — Tue, 07 Jul 2026 14:24:17 GMT

Thanks, I got it working but the logic for setting the previous ID is wrong, it's always grabbing that first ID and never updating it. I solved it by creating two variables called prevID and newID that says

prevID: [Var.newID = null ? "" :Var.newID]
newID: [row1.ID]

Then I updated the prevDesc variable to say [(row1.Description == null || row1.Description.length() < 1) && Var.oldID.equals(Var.newID) ? Var.prevDesc :row1.Description]

Re: tMemorizeRow only filling blank data once

DaniZ — Tue, 07 Jul 2026 14:08:10 GMT

Happy it worked out.

BTW - You COULD have used tMemorizeRow before the tMap just to get the current and previous IDs without having to use the extra Var to determine prevID...

Re: tMemorizeRow only filling blank data once

jeanjpotgieter — Tue, 07 Jul 2026 14:21:27 GMT

Noted. I was already creating vars so I figured might as well keep it consistent