I am working on one scenario.
I have an object called "Property_Assignment__c" which has two record types.
1) Primary Property Assignment
2) Secondary Property Assignment
Its also having a self lookup relationship and this lookup field "Primary_Assignemnt__c" is available on "Secondary Property Assignment" page layout which is lookup to "Primary Property Assignment".
Now if I create any records in "Secondary Property Assignment" record type then I need to count and save in "Number_Of__Dependents" field in "Primary Property Assignment".
Can anyone help me to solve this problem if possible please.
If you want to count the Secondary Property Assignment records you should go with trigger only. we can use Rollup summary to count the no of Secondary Property Assignment records when the master-detail relationship is available.
But here u have self-relationship. So you can write a trigger to count the no of records.
Related
I'm trying to model the following relationships between entities, mainly consisting of a partial, disjoint generalization.
original EERD
'mapped' to relational
Since I didn't need the subclasses to have any particular attributes I decided to use the "single table inheritance" approach, added the "type" field and moved the relationships towards the parent.
After that I had two choices to make:
1- type for the "business type" attribute
2- way to constraint participation to at most one of the 4 relationships based on the type attribute
For the sake of portability and extensibility I decided to implement no.1 as a lookup table (rather than enum or a hardcoded check).
About no.2 I figured the best way to enforce participation and exclusivity constraints on the four relationships would be a trigger.
The problem is that now I'm not really sure how to write a trigger function; for instance it would have to reference values inserted into business type, so I'd have to make sure those can't be changed or deleted in the future.
I feel like I'm doing something wrong so I wanted to ask for feedback before going further; is this a suitable approach in your opinion?
I found an interesting article describing a possible solution: it feels a bit like an 'hack' but it should be working
(it's intended for SQL Server, but it can be easily applied in postgres too).
EDIT:
It consists in adding a type field to the parent table, and then have every child table reference said field along with the parent's id by using a foreign key constraint (a UNIQUE constraint on this pair of fields has to be added beforehand, since FKs must be unique).
Now in order to force the type field to match the table it belongs to, one adds a check constraint/always generated value ensuring that the type column always has the same value
(eg: CHECK(Business_type_id = 1) in the Husbandry table, where 1 represents 'husbandry' in the type lookup table).
The only issue is that it requires a whole column in every subclass, each containing the same generated value repeated over and over (waste of space?), and it may fall apart as soon as the IDs in the lookup table are modified
Does a weak entity need a partial key? Or can you just use its parent key as its primary key.
i.e Order and OrderItem. Order has a PK OrderPK, whilst OrderItem has no partial key.
Is this considered bad practice?
The OrderItem table should have an OrderID field that makes a FK reference back to the Orders table. This assures each item is for a valid order.
Then there is usually another field with distinguishes each item which would be used together with the OrderID field to form the primary key for the item.
This could be an intrinsic value or values that is unique for each item within an order. SKU or PartNum might be just such a value, assuming that multiple occurrences of the same item would be merged into one entry. To find this value, just ask yourself what minimum amount of data would you need to uniquely identify one item from another within the same order. However, it may not be possible. A disadvantage of this scheme is that you could be using dynamic data for a key field. The SKU of a particular item could well change some time in the future.
Or there could be a sequential value (1, 2, 3,...) for each item in an order. A disadvantage with this scheme is the sequential values cannot be system generated. Each sequence is unique for each order and this must be generated by trigger or application code.
Or there could be a system-generated sequential value unique to all the items for all the orders and this field could be the lone primary key. Per-order sequential values could still be generated by row_number functions in queries, but this means a particular item could have different values in different queries. That may or may not be a problem.
At this point, only you know enough about your system to choose the best option. But it is generally necessary for users to be able to select one specific item of one specific order, so some sort of key definition for each item is usually necessary.
I have two entities, Bookings and Discharge.
When a record is created in Bookings, it automatically creates a record in Discharge. Discharge
has an additional field that is a drop down with four options.
I want a functionality where when any one of the values in drop down is chosen, the similar record in Bookings
should shift from "Active" view to a default view which I have created by the name of "Processed" in Bookings.
What I have in mind is to create a hidden field in Bookings that is populated when I choose one of the options from Discharge drop down and based on that field the record should shift the view in Bookings. But how do I populate the hidden field? Workflow is not giving me that option or maybe I am doing something wrong.
Help?
So I have created a 1:N relationship between Booking and Discharge. The field is updated in Booking based on the field in Discharge and I choose the particular record in Booking from the look up field in Discharge. But I want to get rid of this second step. I don't want to choose the record in Booking entity but directly update it from Discharge. There are some fields and their values common in both forms, can I create a relationship based on that?
Regarding the first part of your question
"What I have in mind is to create a hidden field in Bookings that is populated when I choose one of the options from Discharge drop down and based on that field the record should shift the view in Bookings. But how do I populate the hidden field?"
If the field is not on a form you can't set its value hence the following:
I don't believe you can set a hidden field using a workflow. However there is a 'visibility' option on the form designer.
I suggest you add your "hidden" field to the form. Then double click on it and toggle the "Visible by default" checkbox. This will hide the field from the user.
You can then set the value of this field using a workflow.
Regarding part two of your question
I don't want to choose the record in Booking entity but directly update it from Discharge. There are some fields and their values common in both forms, can I create a relationship based on that
You have a 1:N relationship however you want to set the related Booking Dynamically is this correct? You cannot select a Booking in the lookup field based on criteria from a workflow. You would need to use a plugin.
If the Discharge has a related Booking (the Booking lookup on Discharge is already set) then you can use a workflow to either:
1) Set a field value (Using 'Update Record' in the Workflow steps) in the parent Booking
2) set to Inactive (Using 'Change Status' in the Workflow steps) in the parent Booking
I have a Filemaker database with a Members table, an Events table, and a join table called Attendance which should list which members attended which events. Attendance has the setting "allow creation of new records" ticked for Members (doesn't need it for Events).
Data arrives in an Excel spreadsheet for importing to Attendance. But then I want to see if there are people attending who aren't in our records already... sort of like this:
look at each of the newly added records in the attendance table
see if the members mentioned there exist in the member table
if so, do nothing
else create a new record in the member table for them, using data from the attendance table.
If I'm understanding it correctly, Steps 3 and 4 should look something like this:
Set Variable [ $fname; Value: Attendance::firstname ]
Go To Layout ["Member" (Firstname)]
New Record/Request
Set Field [Member::Firstname; $fname]
i.e. put the desired info into variables, start a new record in the related table and set the data there to the value of the variables.
But how do I get step 2 happening? I'm guessing some sort of loop will go through the found set of records in Attendance, and grab the relevant identifier. How do I show that to the Member table to see if it's present or not?
"Firstname" might be a bit light to pinpoint a unique member, if you have many members !
I'd presume therefore you would have some sort of unique key for each member.
As from there, just search for the member in the member base, before creating the new record…
Link the two tables with an EQUALS relationship.
Write a script:
// Loop through your attendance records.
// Be sure you're in the correct layout
Go to Layout ["imported list"]
// Attempt to go to the membership record of the person who is attending the event.
Go to Related Record [Show only records from: from table: "membership table"; using layout: "membership table"
// If the person who is attending IS in the membership list, you'll go to that member's record in the "membership table."
// If the person who is attending is NOT in the membership list, you'll get an error. You can use that error in an if statement to execute code to add that member.
If [Get ( LastError ) = "101"]
// insert code to add new member
End if
Since you already have a relationship between Member and Attendance, it means that you can "see" any related Members from the Attendance table across the relationship.
We also know that you only need to evaluate the new attendance records coming in from your spreadsheet.
I also assume that there could possibly be be more than one attendance record per Member in the spreadsheet. This may not be the case, but it's safer to assume it's possible.
I'm also assuming that you are linking the Member table to the Attendance table via the primary key in Members and a foreign key in Attendance, i.e. Member::ID = Attendance::Member ID.
So here's the script process I suggest:
Import the new Attendance record into the Attendance table.
This will give you a found set of only new attendance records
From the Attendance layout, perform a find for related Member records with an omit, i.e.:
# This assumes you're already on the Attendance layout
Enter Find Mode
Set field [Member::ID ; "*"]
Omit record
Constrain Find
This will give you a found set of new Attendance records that do not have matching Member records.
From here you could loop through each of the attendance records and create the Member records as needed.
If you check the Allow creation on the Member side of the Member -< Attendance relationship, you could set the field in the Member table directly from the Attendance layout.
Since the 1 to Many relationship between Member and Attendance goes 1=Member Many=Attendance, you would need to check to be sure you haven't already created a Member record during your loop, i.e. If a new Member had multiple Attendance records you could have already created a Member record during the loop.
Your loop would look like this:
Go to Record [First]
Loop
If [IsEmpty(Member::ID)]
Set Field [Member::First Name] // This first Set Field will create your new Member Record as long as the "Allow Creation" is enabled on the Member side
Set Field [Member::Last Name]
... This would be the rest of your set field steps for Member
End If
Go to Record [Next ; Exit After Last]
End Loop
This way you don't need to navigate away from your Attendance record set. Also, the Primary and Foreign keys for both tables will be created and set automatically through the attributes of the relationship itself.
In most cases, we can map a field in a table either to a property or we can map it using conditional mapping, but not both. Only exception is if condition is set to Is NotNull, since then we can also map to a column.
a) Is this the reason why we are able to map a DB column only once - namely, if field was allowed to have both a property mapping and a conditional mapping, then property mapping would tell EF to retrieve all table rows, while conditional mapping would tell EF to retrieve only those rows that satisfy the condition?!
b) If my reasoning under a) is correct, then why is field allowed to have both mappings when condition is set to Is NotNull? Why won't that create a conflict?
Thank you
Mapping with condition Is NotNull has special meaning because it requires subsequent change in your model. The mapped property in the model must not be nullable. So your column in the database is nullable, your mapping condition filters all records with null value and your property always receives only records with non-null values. Also you can never assign null to the property.
In case of common condition with value equality this special behaviour is not possible.