MDR clarification - triggers

Setup:
I have a MDR relationship as shown below:
Event --< Attendee >-- Contact
There is a trigger on EVENT that fires before insert and before update that calculaes the number of attendees (by searching for the number of occurances of the Event's ID in the attendees object.
Question:
When I'm adding a record to the ATTENDEE why is my trigger being fired on the EVENT object?!
Thanks!

When a change to a detail record (in a Master-Detail relationship) causes a roll-up summary on the Master record to change, it may cause Trigger(s) on the Master record to execute.
The Roll Up Summary Field Technology Overview knowledge article, in Salesforce help, explains it well:
Incremental Updates
When a summarized record changes we determine whether that change would lead to a change in the RSF value. If so, we calculate a delta value, which is then applied to the RSF in the summarizing record in the same transaction. We perform this operation in memory. No additional database call is required. Updates are only performed for the row(s) with RSF that actually changed. If the summarizing row itself is summarized the process continues to the grandparent. All validations, triggers, workflow, etc, for the summarizing row are necessarily executed when they are changed. All Incremental updates are performed to 38 digits of precision.
Also, see page 79 of the the Spring '09 release notes for more detail.
Workflow Rule and Roll-Up Summary Field Evaluations
The Spring '09 Workflow Rule and Roll-Up Summary Field Evaluations update affects the way Salesforce evaluates workflow rules and roll-up summary fields on objects with Apex triggers. The update improves the accuracy of your data and prevents the reevaluation of workflow rules in the event of a recursion. A recursion is a situation in which a part of your custom logic (such as a roll-up summary field or Apex trigger) causes Salesforce to execute the logic twice when saving a record, often resulting in undesirable behavior. For more information, see "What is the Spring '09 Workflow Rule and Roll-Up Summary Field Evaluations Update?" in the Salesforce online help.

Related

Postgresql RULE order

What is the order that RULEs fire when applied to an INSERT?
Are they done AFTER or BEFORE the record is inserted.
What I am trying to do is create a new record in another table, which will link to the record that was INSERTed.
Take for example; To make a rule that will creating a new page, when a document is created, so that a document will always start with an empty page record.
I have looked high and low, and maybe I'm asking Google the wrong question, but I cannot find any documentation about the order of execution for RULES.
Quote from the manual
Multiple rules on the same table and same event type are applied in alphabetical name order.
So the ordering does not depend on the type of the rule, only on the name.
And it also explains how the rule is "applied"
It is important to realize that a rule is really a command transformation mechanism, or command macro. The transformation happens before the execution of the command starts.
Emphasis mine
So the rule doesn't happen "before" or "after" a statement runs - it runs instead of that statement.
What I am trying to do is create a new record in another table, which will link to the record that was INSERTed.
You definitely want an AFTER INSERT trigger for that. Forget about rules.
Which is also what the manuals recommends:
If you actually want an operation that fires independently for each physical row, you probably want to use a trigger, not a rule

building audit trail functionality

Following is a use case in a workflow system
Work order enters into a system. Work order will have a target which goes through different workflow states before completing a work order.
Say Work order for a target Vehicle came into a system - workflow for this work oder involves 2 tasks say
a)wash vehicle
b)inspect vehicle
Say wash vehicle workflow task changes vehicle attribute from "not washed" to "washed". And say "inspect vehicle" workflow task changes vehicle attribute "not inspected" to "inspection done"
If user is pulling work order data user will always see latest vehicle data (in this example assuming both workflow tasks are completed user will see value "washed" and "inspection done". However when user pulls ONLY workflow Task Wash Vehicle data -> user will see "washed" -Though second task was done, workflow Task 1 will only see that that it modified. Getting data for Workflow Task 2 will see both "washed" and "inspection done"
This involves milstoning (audit trail) of data; One approach is as shown below image - where when workflow task modifies data it'll update version number, modified_ts and maintain that version number in it's own data row (via a JOIN table as depicted below). Basically this is nothing but maintaining a reference to a history record for workflow task data so when pulling workflow task data it knows which history record to pull back. please ignore parent_id and other notes, noise in a below picture. it's not relevant for this question.
I am thinking event sourcing will also be another alternative design - however don't want to apply event sourcing(or any other similar solution) as a whole sale solution but only for this particular use case (affecting only 3 or so tables where audit trail matters). I am trying to evaluate if CQRS/Event sourcing is a right fit as a partial solution (again only limited to 3-4 tables which need to preserve history/audit trail data) or ES/CQRS will be an overkill? any other thoughts?
P.S. Though this isn't related to Scala - Scala is a platform we are using hence tagging it to see if there are language specific solutions that can help. tagging Akka for finding out if ES/CQRS via Akka persistence is an option or not. Postgresql is a db - And DB triggers is not a solution I am looking for.

In which order are workflow items processed?

I have a number of workflow items on cases in SuiteCRM.
How can I determine the order in which these items are processed? In my situation, I am setting the priority of the case based on the values of some integer fields. However, these integer fields must first be populated based on the values of some dropdowns.
How can I make sure they are populated in the correct order? I can't see an order of execution with the workflow items.
Workflow simply pulls the workflow items to run using get_full_list which will just give the items in whatever order the database returns them (probably by id).
The alternatives are to add a new hidden flag field to the case to signify that the values have been set then check this in the workflow conditions.
Allowing setting a priority for a workflow would be a good addition however and I've added this on the SuiteCRM GitHub: https://github.com/salesagility/SuiteCRM/issues/280

Salesforce.com: UNABLE_TO_LOCK_ROW, unable to obtain exclusive access to this record

In our production org, we have a system of uploading sales data into Salesforce using command line data loader. This data is loaded into a temporary object Temp. We have created a formula field (which combines three fields) to form a unique key. The purpose of the object is to reduce user efforts for creating the key manually.
There is an after insert trigger on Temp which calls an asynchronous method which upserts the data to another object SalesData using the key. The insert/update trigger on SalesData checks the various fields and creates/updates the records in another object SalesRecords. After the insertion/updation is complete, all the records in temp object Temp are deleted. The SalesRecords object does not have any trigger on it and is a child of another object Sales. The Sales object has some rollup fields which are summing up fields from SalesRecords object.
Lately, we are getting the below error for some of the records which are updated.
UNABLE_TO_LOCK_ROW, unable to obtain exclusive access to this record
Please provide some pointers to resolve the issue
this could either be caused by conflicting DML operations in the various trigger execution or some recursive trigger execution. i would assume that the async executions cause multiple subsequent updates on the same records, probably on the SalesRecords object. I would recommend to try to simplify the process to avoid too many related trigger executions.
I'm a little surprised you were able to get this to work in the first place. After triggers should be used with caution and only when before triggers can't be. One reason for this is that you don't need to perform additional DML to make changes to records, since in before triggers you simply change the values and the insert/update commit happens automatically. But recursive trigger firings is the main problem with after triggers.
One quick way to avoid trigger re-entry is to use a public static Boolean in a class that states whether you're already in this trigger from the same thread of execution.
Something like:
public static Boolean isExecuting = false;
Once set to true, any trigger code that is a re-fire can be avoided with:
if(Class.isExecuting == false)
{
Class.isExecuting = true;
// Perform trigger logic
// ...
}
Additionally, since the order of trigger execution cannot be determined up front, you might be seeing an issue with deletions or other data changes that depend on other parts of your flow to finish first.
Also, without knowing the details of your custom unique 3-part key, I'd wonder if there's a problem there too such as whether it's truly unique or not. Case insensitivity is a common mistake and it's the reason there are 15 AND 18 character Ids in Salesforce. For example, when people export to Excel (a case-insensitive environment) and do VLOOKUPs, they would occasionally find the wrong record. The 3-digit calculated suffix was added to disambiguate for case-insensitive environments.
Googling for this same error lead me to this post:
http://boards.developerforce.com/t5/General-Development/Unable-to-obtain-exclusive-access-to-this-record/td-p/345319
Which points out some common causes for this to happen:
Sharing Rules are being calculated.
A picklist value has been replaced and replacement is in progress.
A custom index creation/removal is in progress.
Most unlikely one - someone else is already editing the same record that you are trying to access at the same time.
Posting here in case somebody else needs it.
I got this error multiple times today. Turned out one of our vendors was updating their installed package during that time in the same org. All kinds of things were going wrong also - some object validation exceptions were being thrown on DMLs, without any error message content.
Resolution
The error is shown when a field update such as a roll-up summary field is being attempted on a parent object that already had a field update to cause the roll-up summary field to calculate. This could also occur if a trigger or another apex job running on the master object and it also attempting to do an update.
You can either reduce the batch size and try again or create separate smaller files to be imported if this issue occurs.

Last Updated Date: Antipattern?

I keep seeing questions floating through that make reference to a column in a database table named something like DateLastUpdated. I don't get it.
The only companion field I've ever seen is LastUpdateUserId or such. There's never an indicator about why the update took place; or even what the update was.
On top of that, this field is sometimes written from within a trigger, where even less context is available.
It certainly doesn't even come close to being an audit trail; so that can't be the justification. And if there is and audit trail somewhere in a log or whatever, this field would be redundant.
What am I missing? Why is this pattern so popular?
Such a field can be used to detect whether there are conflicting edits made by different processes. When you retrieve a record from the database, you get the previous DateLastUpdated field. After making changes to other fields, you submit the record back to the database layer. The database layer checks that the DateLastUpdated you submit matches the one still in the database. If it matches, then the update is performed (and DateLastUpdated is updated to the current time). However, if it does not match, then some other process has changed the record in the meantime and the current update can be aborted.
It depends on the exact circumstance, but a timestamp like that can be very useful for autogenerated data - you can figure out if something needs to be recalculated if a depedency has changed later on (this is how build systems calculate which files need to be recompiled).
Also, many websites will have data marking "Last changed" on a page, particularly news sites that may edit content. The exact reason isn't necessary (and there likely exist backups in case an audit trail is really necessary), but this data needs to be visible to the end user.
These sorts of things are typically used for business applications where user action is required to initiate the update. Typically, there will be some kind of business app (eg a CRM desktop application) and for most updates there tends to be only one way of making the update.
If you're looking at address data, that was done through the "Maintain Address" screen, etc.
Such database auditing is there to augment business-level auditing, not to replace it. Call centres will sometimes (or always in the case of financial services providers in Australia, as one example) record phone calls. That's part of the audit trail too but doesn't tend to be part of the IT solution as far as the desktop application (and related infrastructure) goes, although that is by no means a hard and fast rule.
Call centre staff will also typically have some sort of "Notes" or "Log" functionality where they can type freeform text as to why the customer called and what action was taken so the next operator can pick up where they left off when the customer rings back.
Triggers will often be used to record exactly what was changed (eg writing the old record to an audit table). The purpose of all this is that with all the information (the notes, recorded call, database audit trail and logs) the previous state of the data can be reconstructed as can the resulting action. This may be to find/resolve bugs in the system or simply as a conflict resolution process with the customer.
It is certainly popular - rails for example has a shorthand for it, as well as a creation timestamp (:timestamps).
At the application level it's very useful, as the same pattern is very common in views - look at the questions here for example (answered 56 secs ago, etc).
It can also be used retrospectively in reporting to generate stats (e.g. what is the growth curve of the number of records in the DB).
there are a couple of scenarios
Let's say you have an address table for your customers
you have your CRM app, the customer calls that his address has changed a month ago, with the LastUpdate column you can see that this row for this customer hasn't been touched in 4 months
usually you use triggers to populate a history table so that you can see all the other history, if you see that the creationdate and updated date are the same there is no point hitting the history table since you won't find anything
you calculate indexes (stock market), you can easily see that it was recalculated just by looking at this column
there are 2 DB servers, by comparing the date column you can find out if all the changes have been replicated or not etc etc ect
This is also very useful if you have to send feeds out to clients that are delta feeds, that is only the records that have been changed or inserted since the data of the last feed are sent.