For the first time, I am developing in an environment in which there is a central repository for a number of different industry standard reference data tables and many different customers who need to select records from these industry standard reference data tables to fill in foreign key information for their customer specific records.
Because these industry standard reference files are utilized by all customers, I want to reserve Create/Update/Delete access to these records for global product administrators. However, I would like to implement a (semi-)automated interface by which specific customers could request record additions, deletions or modifications to any of the industry standard reference files that are shared among all customers.
I know I need something like a "data change request" table specifying:
user id,
user request datetime,
request type (insert, modify, delete),
a user entered text explanation of the change request,
the user request's current status (pending, declined, completed),
admin resolution datetime,
admin id,
an admin entered text description of the resolution,
etc.
What I can't figure out is how to elegantly handle the fact that these data change requests could apply to dozens of different tables with differing table column definitions. I would like to give the customer users making these data change requests a convenient way to enter their proposed record additions/modifications directly into CRUD screens that look very much like the reference table CRUD screens they don't have write/delete permissions for (with an additional text explanation and perhaps request priority field). I would also like to give the global admins a tool that allows them to view all the outstanding data change requests for the users they oversee sorted by date requested or user/date requested. Upon selecting a data change request record off the list, the admin would be directed to another CRUD screen that would be populated with the fields the customer users requested for the new/modified industry standard reference table record along with customer's text explanation, the request status and the text resolution explanation field. At this point the admin could accept/edit/reject the requested change and if accepted the affected industry standard reference file would be automatically updated with the appropriate fields and the data change request record's status, text resolution explanation and resolution datetime would all also be appropriately updated.
However, I want to keep the actual production reference tables as simple as possible and free from these extraneous and typically null customer change request fields. I'd also like the data change request file to aggregate all data change requests across all the reference tables yet somehow "point to" the specific reference table and primary key in question for modification & deletion requests or the specific reference table and associated customer user entered field values in question for record creation requests.
Does anybody have any ideas of how to design something like this effectively? Is there a cleaner, simpler way I am missing?
Option 1
If preserving the base tables is important then I would create a "change details" table as a child to your change request table. I'm envisioning something like
ChangeID
TableName
TableKeyValue
FieldName
ProposedValue
Add/Change/Delete Indicator
So you'd have a row in this table for every proposed field change. The challenge in this scenario is maintaining the mapping of TableName and FieldName values to the actual tables and fields. If your database structure if fairly static then this may not be an issue.
Option 2
Add a ChangeID field to each of your base tables. When a change is proposed add a record to the base table with the ChangeID populated. So as an example if you have a Company table, for a single company you could have multiple records:
CompanyCode ChangeID CompanyName CompanyAddress
----------- -------- ----------- --------------
COMP1 My Company Boston <-- The "live" record
COMP1 1 New Name Boston <-- A proposed change
When the admin commits the change the existing live record is deleted or archived and the ChangeID value is removed from the proposed record making it the live record. It may be a little tricky to handle proposed deletions with this option. This option also has the potential for impacting performance of selecting live data for normal usage. However it does save you the hassle of maintaining a list of table names and field names somewhere in your code.
I'm sure others will have some opinions!
Related
I am working on a data warehouse solution, and I am trying to build a dimensional model from tables held in a SQL Server database. Some of the tables include but aren't limited to Customer, Customer Payments, Customer Address, etc.
All these tables in the DB have some fields that are repeated multiple times across each table i.e. Record update date, record creatuin date, active flag, closed flag and a few others. These tables all relate to the Customer in some way, but the tables can be updated independently.
I am in the process of building out a dimension(s) on the back of these tables, but I am struggling to see how best to deal with these repeated fields in an elegant way, as they are all used.
I'll appreciate any guidance from people who have experience with scenarios like this, as I ammjust starting out
If more details are needed, I am happy to provide
Thanks
Before you even consider how to include them, ask if those metadata fields even need to be in your dimensional model? If no one will use the Customer Payment Update Date (vs Created Date or Payment Date), don't bring it into your model. If the customer model includes the current address, you won't need the CustomerAddress.Active flag included as well. You don't need every OLTP field in your model.
Make notes about how you talk about the fields in conversation. How do you identify the current customer address? Check the CurrentAddress flag (CustomerAddress.IsActive). When was the Customer's payment? Check the Customer Payment Date (CustomerPayment.PaymentDate or possibly CustomerPayment.CreatedDate). Try to describe them in common language terms. This will provide the best success in making your model discoverable by your users and intuitive to use.
Naming the columns in the model and source as similar as possible will also help with maintenance and troubleshooting.
Also, make sure you delineate the entities properly. A customer payment would likely be in a separate dimension from the customer. The current address may be in customer, but if there is any value to historical address details, it may make sense to put it into its own dimension, with the Active flag as well.
I'm creating a rather large APEX application which allows managers to go in and record statistics for associates in the company. Currently we have a database in oracle with data from AD which hold all the associates information. Name, Manager, Employee ID, etc.
Now I'm responsible for creating and modeling a table that will house all their stats for each employee. The table I have created has over 90+ columns in it. Some contain data such as:
Documents Processed
Calls Received
Amount of Doc 1 Processed
Amount of Doc 2 Processed
and the list goes on for well over 90 attributes. So here is my question:
When creating this table in my application with so many different columns how would I go about choosing a primary key that's appropriate? Should I link it to our employee table using the employees identification which is unique (each have a associate number)?
Secondly, how can I create these tables (and possibly form) to allow me to associate the statistic I am entering for an individual to the actual individual?
I have ordered two books from amazon on data modeling since I am new to APEX and DBA design. Not a fresh chicken, but new enough to need some guidance. An additional problem I am running into is that each form can have only 60 fields to it. So I had thought about creating tables for different functions out of my 90+ I have.
Thanks
4.2 allows for 200 items per page.
oracle apex component limits
A couple of questions come to mind:
Are you sure that the employee Ids are not recyclable? If these ids are unique and not recycled.. you've found yourself a good primary key.
What do you plan on doing when you decide to add a new metric? Seems like you might have to add a new column to your rather large and likely not normalized table.
I'd recommend a vertical table for your metrics.. you can use oracle's pivot function to make your data appear more like a horizontal table.
If you went this route you would store your employee Id in one column, your metric key in another, and value...
I'd recommend that you create a metric table consisting of a primary key, a metric label, an active indicator, creation timestamp, creation user id, modified timestamp, modified user id.
This metric table will allow you to add new metrics, change the name of the metric, deactivate a metric, and determine who changed what and when.
This would be a much more flexible approach in my opinion. You may also want to think about audit logs.
I want to design a database to store insurance policy information. (No, I'm not building Healthcare.gov)
A policy is uniquely described by it's PolicyNumber. Some other attributes are EffectiveDate, ExpirationDate, and Premium (among others).
Here's the catch - things like Premium and ExpirationDate can change after the policy has been written, due to a cancellation, audit, etc.
For my purposes, I need to know what the premium and expiration date was as it was written and as it is now. However, there are attributes like EffectiveDate that will remain static from the time the policy was written. So, how do I build a normalized database to capture all of this?
One way to go about this is to create a normal policy table that would contain all the up-to-date information. Create another table that would contain the history data you wish to track. You may want to keep timestamp information on both but specially on the history table. You may want to build a 1-M relationship between the main table and the history table since you could have several history rows for any active row. The absence of history rows would mean that there are no changes made.
Every time a change is made, the current row in the policy table (or if you wish, the relevant columns) are copied to the history table and the history row is saved.
A problem with this design is that it may be a bit of work to figure out what changed (unless the client could pass this info) and that it would waste some space.
This design has the advantage of being simple and that it keeps all current information in 1 place. Current information is what you'd normally access in most of the system's operations (I'd guess).
(Sorry about the vagueness of the title; I can't think how to really say what I'm looking for without writing a book.)
So in our app, we allow users to change key pieces of data. I'm keeping records of who changed what when in a log schema, but now the problem presents itself: how do I best represent that data in a view for reporting?
An example will help: a customer's data (say, billing address) changed on 4/4/09. Let's say that today, 10/19/09, I want to see all of their 2009 orders, before and after the change. I also want each order to display the billing address that was current as of the date of the order.
So I have 4 tables:
Orders (with order data)
Customers (with current customer data)
CustomerOrders (linking the two)
CustomerChange (which holds the date of the change, who made the change (employee id), what the old billing address was, and what they changed it to)
How do I best structure a view to be used by reporting so that the proper address is returned? Or am I better served by creating a reporting database and denormalizing the data there, which is what the reports group is requesting?
There is no need for a separate DB if this is the only thing you are going to do. You could just create a de-normalized table/cube...and populate and retrieve from it. If your data is voluminous apply proper indexes on this table.
Personally I would design this so you don't need the change table for the report. It is a bad practice to store an order without all the data as of the date of the order stored in a table. You lookup the address from the address table and store it with the order (same for partnumbers and company names and anything that changes over time.) You never get information on an order by joining to customer, address, part numbers, price tables etc.
Audit tables are more for fixing bad changes or looking up who made them than for reporting.
Say you have a ServiceCall database table that records down all the service calls made to you. Each of this record contains a many to one relationship to Customer record, where it stores which customer made the Service Call.
Ok, suppose the Customer has stop doing business with you and you do not need the Customer's record in your database. No longer need the Customer's name to appear in the dropdown list when you create a new ServiceCall record.
What do you do?
Do you allow the user to delete the Customer's record from the database?
Do you set a special column IsDeleted to true for that Customer's record, then make sure all dropdown list will not load all records that has IsDeleted set to true? Although this keeps the old records from breaking at innerjoins, it also prevents user from adding a new record with the same name as the old Customer, won't it?
Do you disallow deletion at all? Just allow to 'disable' it?
Any other strategies you used? I am guessing everyone have their way, I just need to see your opinions.
Of course the above is quite simplified, usually a ServiceCall record will link to many other entity tables. All of which will face the same problem when they are required to be deleted.
I prefer to set an IsDeleted flag, one of the benefits is you can still report on historical information (all teh data is still there).
As to the issue of not being able to insert another customer with the same name, this isn't a problem if you use an ID column (eg CustomerId) which is generally auto populated.
I agree with #Tetraneutron's answer.
Additionally, you can create a VIEW that lists only the active customers, to make it more convenient to populate drop-down lists and such.