passing values from child to parent package

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passing values from child to parent package

kbatta

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June 20, 2008 at 5:56 am

#123427

Can a child package change the value of variables in the parent package? If not, what is a good way to pass values back to the parent?
I am developing a large application where most of the activity will occur in several child packages and a parent package will run them in sequence. Changing the value of a variable in the parent will make the new value available for the rest of the children.

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KenpoDBA SSCrazy Eights Points: 9811 More actions · Answer 1

I'm not sure, but my initial thought is no.

However, the easiest way to get it done is to have the child save the new value to a table and just have the parent read that table and assign the var to the result. Now you're always up to date.

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kbatta SSCrazy Points: 2274 More actions · Answer 2

Thanks! I finally got a chance to experiment Friday afternoon at work. It looks like it is possible if you let the child reach into the parent for variables. But I ran into other problems with this approach. Your idea of the table sounds safer.

Gordon Radley SSCommitted Points: 1776 More actions · Answer 3

crever is correct that one option would be to use a SQL table to communicate between parent and child packages.

You can also use Package Configurations to pass data from parent to child and back again. There is a configuration type called "Parent Package Variable" which will require you to enter the Parent Package variable name prefixed with User:: or System:: depending on the type of variable you are retrieving. You can then update the variable value in the child package and it will be returned to the parent.

kbatta SSCrazy Points: 2274 More actions · Answer 4

kbatta

SSCrazy

Points: 2274

June 23, 2008 at 4:14 pm

#833063

Thanks!

Paul Williams SSCommitted Points: 1930 More actions · Answer 5

Another option is to use the raw data file.

This acts just like a staging area as with the first suggestion but has the advantage of not requiring creation of a physical table.

It depends upon your exact requirements though the Package Configs for Parent variables is your best option depending upon the amount of data.

Paul R Williams.

kbatta SSCrazy Points: 2274 More actions · Answer 6

Thanks! The amount of data that needs to be passed is small in this case. But this gives me 3 different approaches depending on the situation.

kbatta SSCrazy Points: 2274 More actions · Answer 7

Here is a way for a child package to change variables in the parent package.

In the child package,

1. Define the variables that you need. But DO NOT INCLUDE the ones that you want to update in the parent. If you need a variable for them, give it a different name.

2. Define a package configuration for each variable whose value you want from the parent. DO NOT INCLUDE the ones you want to update. If you need them, then map them to a different name.

3. To easily reference and update variables, please see Daniel Read's blog. (http://www.developerdotstar.com/community/node/512/)

I learned from his blog that it is better to use the variable dispenser than the readonly and readwrite sections of the script task or component. Otherwise, the variables tend to be locked too long, increasing the risk of a deadlock if you have multiple threads running.