I’m absolutely stumped by what I suspect is probably simple for those experienced with Access. I’m brand new to Access (2010) and studying a lot, but unfortunately still confused by many basic concepts. I’m embarrassed to admit that I have spent about 40 hours trying (unsuccessfully) to solve the specific issue below. Please forgive me if I haven’t included enough detail here - I’m not sure how much someone needs to know to address this. I’m happy to edit and/or provide more information.
My question:
How do I create a Form for creating new records / editing existing records in Table1 where two fields in Table1 have different values from a single field in Table2? (I have better detail below)
I want the Form to have all the records from Table1. I have tried many different ways with queries, sub-forms, etc., but can’t pull it off. I’m fairly certain the issue is related to how I address Table2. Ideally, the user would be able to select from dropdowns in the form for the two fields to be updated in Table1.
I am including screenshots of a mockup of my intended Form concept, the object Relationships as I currently have them, the design and datasheet views of Table1 and the design and datasheet views of Table2.
“Table1” above is “t_PEOPLE” in the images while “Table2” is “t_COLORS.”
The object relationship types are currently one-to-many with enforced referential integrity (cascade update related fields) and the join properties are "include ALL records from 't_PEOPLE' and only those records from 't_COLORS' where the joined fields are equal."
I'm happy to send the actual database file if that helps.
I will be very grateful for any guidance - thank you!!
The general approach to this is as follows:
A) If I understand what you're trying to do here, your t_colors table is usually referred to as a Reference table or Lookup table. You need to make one form to add, edit, and delete records in this t_colors table. How the user accesses that form varies. I'll get to that in a minute.
B) The form for your People table needs to have drop down menus for your two color selections. In the dropdown menus' RowSource, you will use a query that looks up values in your t_colors table.
C) Depending what you are using your colors for in t_people, you should consider making a third table with PeopleID and ColorID in it. It would then link to both t_people and t_colors. This would allow you to have multiple colors specified for a single person, and you wouldn't be limited to two. In your People form, you would use a subform for these colors. The subform would probably need to be a datasheet form or a continuous form. If you are using a datasheet form for your people form, then you would need to use a datasheet form for the colors subform.
If the user wants to use a color that isn't already in your t_colors table, you need to give them a way of inserting that color. There are various approaches to this. You could use a union query in the dropdowns RowSource that shows a "" option. If selected you would bring up your Colors form and when they close the colors form you have to requery your dropdown menu. Or you could insert the color for them using VBA when they enter a value that is "Not In List" (an event that Combobox's have).
Please note that the relationships you've defined are not overly helpful or important in this case. Yes, they can be helpful when it comes to using the Update Cascade or Delete Cascade features. But quite truthfully, relationships are basically for programmers, to make sure you get an error if and when referential integrity is violated. Users should never see these errors and properly designed forms will prevent them from occurring. The main reason to use them is that it will force you to design your forms properly by giving you an error when something is wrong, hopefully during your own testing phase of the project.
Related
I have an app page that shows information from the same table in 2 places on a page.
In the place A, I want an editable field that is owned by the current user.
In the place B, I want to see the list of entries for all users.
I thought I could somehow have two pointers into the same table by configuring more than one datasource for the table, and bind placeA/B widgets to the two separate datasource.
However, I could not find out how I can bind a panel or widget to a specific datasource within a table.
What bugs me is that clearly the UI allows me to add multiple datasources for a table, so I probably misunderstand what the usercase for multiple datasources are.
My current plan is to ivestigate whether I can create a computed datasource that limits results to just the current user, but I don't understand how I could updated a computed datasource (which is something I want to do).
This is probably less than clear, happy to add clarifying information.
Many thanks in advance for any help
Never mind. App maker behaves as I thought it should be. The two datasources are behaving as two cursors into the same table. For some reason, I could not seem to find the 2nd datasource in the widget dropdown for datasource, but I could find it by selecting "Advanced" and then finding datasource starting from "datasources" instead of "widget.datasource".
Nothing to see here, move along now ;)
I have a problem I'm trying to solve and I'm really not sure I'm, A) solving it the correct way, and B) able to do what I want.
I have a List Page that is a basically a summary table (transportation table) that has a record in it for every Sales, Purchase, and Transfer order that we will ship. With it is a pile of rolled up information and such that's common from the 3 sources. We use this table on a few list pages and link out to where we need to. This was all built by someone else, but I'm maintaining some parts around it.
I've gotten a request to have the preview pane on a summary table based list page show the lines from the source order. So, if a "sales order" is selected in the grid, show the lines in the preview pane for the "sales order" that was selected. Same for a purchase order and transfer order.
So, my idea, based on pure ignorance and not a ton of experience with Dynamics is that I would just swap out the preview pane based on the source order. The SalesTableListPagePreviewPane for instance has already been updated to work with linking to this summary table. So, I wanted to just change the part reference at runtime.
I've managed to get the FormRun on a list page interaction class from the datasource. I've managed to get a list of the parts via the PartList object. But, I have no idea how to continue on to actually swap out a part reference.
Am I heading down the correct path? Is this a completely wrong Dynamics AX pattern?
Your assumption, that you can dynamically (run-time) change the parts of the form, is wrong.
Listpages especially are quite static, the only code available through interaction classes. It has the benefit that a listpage can be easily deployed on Sharepoint Enterprise Portal.
You have several options:
Use 3 different listpages for each type of transport
Use a common relation table with 3 sub-tables (sales, purchase and transfer)
The last option will enable you to do an outer join on the 3 sub-tables.
The common relation table could be a union view, but I doubt it will perform well.
I have about 20 different tables that each have a different parent / child relationship built into them. I've recently been asked to create a breadcrumb and Site Map for our website based off of all of these tables.
One idea I had, was to remove the parent / child relationship from each of these tables and create basically one table that holds the id and parentId and whenever I need to pull the parent child relationship I would just join the parent_child_relationships table to whatever table I was pulling from specifically.
Does this make sense?
Anyway, the problem with this idea is that i don't like it. haha.
Does anyone else have any other ideas of how this could be done? Or what the correct way of building a breadcrumb and sitemap based off of a site comprised of 20 tables or so?
If it helps, my site is comprised of asp.net, ColdFusion and uses a MSSQL database.
Thanks!
Do not let the implementation of the UI effect the design of your model and especially not your DB. Prototype the front end, involve your customer(s), give them a voice. Build your breadcrumbs and site map without it initially tied into your actual DB. Once your customer says "thats what we want, just like that", then freeze the prototype, then work on the actual implementation - how will your app request the data, what type of dataobject will you use AND THEN build your db,
"One idea I had, was to remove the parent / child relationship from each of these tables and create basically one table that holds the id and parentId"
This is not a very scalable solution, do not *reverse normalize your db. Follow standard relation database modeling/normalization techniques. Lots of small cohensive tables with lots of association tables.
This is a purely theoretical question (at least until I start trying to implement it) but here goes.
I wrote a web form a long time ago which has a configurable section for getting information. Basically for some customers there are no fields, for other customers there are up to 20 fields. I got it working by dynamically creating the fields at just the right time in the page lifecycle and going through a lot of headaches.
2 years later, I need to make some pretty big updates to this web form and there are some nifty new technologies. I've worked with ASP.NET Dynamic Data just a bit and, well, I half-crazed plan just occurred to me:
The Ticket object has a one-to-many relationship to ExtendedField, we'll call that relationship Fields for brevity.
Using that, the idea would be to create a FieldTemplate that dynamically generated the list of fields and displayed it.
The big questions here would probably be:
1) Can a single field template resolve to multiple web controls without breaking things?
2) Can dynamic data handle updating/inserting multiple rows in such a fashion?
3) There was a third question I had a few minutes ago, but coworkers interrupted me and I forgot. So now the third question is: what is the third question?
So basically, does this sound like it could work or am I missing a better/more obvious solution?
Did you try creating a FieldTemplate that had a "ListView" of all the Fields? (the ListView would use Dynamic Data to determine which FieldTemplate to display for each field.)
I don't see why this would not be possible. Although, "out of the box", you may have to hit "edit" on each row of the new FieldTemplate's ListView to edit the values. It would be like replacing the "Order Details" link in the Orders List, with an inline List of the "Order Details".
1.) Not very nicely. Can you imagine showing a DateTime, Integers, Phone numbers, Urls, etc with just ONE user control, like text.ascx? Why not have multiple field templates and use UIHint to specify usage per column?
2.) Yes.
3.) Define basically?
regarding one to many relationships, you might have a look at the ListDetails.aspx Page Template in Dynamic Data. Hope this helps.
I am facing this question in a new little project:
The system to be built will allow user to add new columns to a table in the system, and then the user will be able to maintain the data, I think there is two ways to implement this:
1) create a few tables including "columns" table with "columnName" "columnValue" "datatype" etc to store the column definition, aonther table "XXCoumn" to store the value of the column (entered by user), and user a store procedure to query/update column data.
2) create the column in the table schema when user enter a new column, then the maintain of the table data is just as normal
which way do you guys reckon? or any new suggestion?
Some additional info: the data volumn is small, and I need to create reports.
Any good recommendations would require a much better understanding of your requirements, but here are some comments on the options you mentioned, as well as some additional thoughts.
1) Entity-Attribute-Value (EAV) Design: This is the option you describe where you have a table that has columns for ColumnName, Type and Value. This option has the advantage of being able to accomodate unlimited new columns easily, but I have found it to be painful when the time comes to retrieve meaningful data back. For example, say you have rows in this EAV table for {Color, varchar}{Red, Green, Blue}, and {Size, varchar}{Small, Medium, Large}. If you want to find all the small green items, you need something like this (untested SQL of course):
SELECT *
FROM ITEMS
WHERE ITEMID IN (SELECT ITEMID
FROM ITEM_ATTRIBUTES ATT INNER JOIN ITEM_VALUES VLS
ON ATT.AttributeID = VLS.AttributeID
WHERE ATT.ColumnName = 'Color' AND VLS.Value = 'Green')
AND ITEMID IN (SELECT ITEMID
FROM ITEM_ATTRIBUTES ATT INNER JOIN ITEM_VALUES VLS
ON ATT.AttributeID = VLS.AttributeID
WHERE ATT.ColumnName = 'Size' AND VLS.Value = 'Small')
Contrast this with having actual columns on the items table for color and size:
SELECT *
FROM ITEMS
WHERE COLOR = 'Green' AND SIZE = 'Small'
In addition, you will have a difficult time maintaining data integrity, if that is important for this app (and it is almost always important, even when you are told otherwise). In the example above, you will need to implement extra logic if "Color" should be limited to Blue, Green, and Red. Also, you will need to implement even more logic if certain colors only come in certain sizes (example - blue items are only available in small and medium)
2) User-Defined Columns: Just giving the user the ability to add additional columns to the table has the advantage of making data retrieval simpler, but all the data integrity issues remain. Also, your app usually requires extra logic to deal with the unknown columns.
3) Pre-Existing Custom Columns: I have worked with a few apps, such as CRMs, that provide a dozen or more columns already in place for user definition. Basically, the designers put in columns like "Text1","Text2","Text3","Number1","Number2", etc. The users then provide header and description information for these columns, and that is what the app uses for display purposes. This model has the advantage of easy data retrieval, as well as a pre-defined DB schema which should simplify app logic. Data integrity issues remain, however. The other obvious downside is that you will run out of pre-defined columns, which is what you are usually trying to avoid with this type of solution.
As with most design issues, there are tradeoffs to each solution. My experience has been that while many users/clients say they want solutions like these, in reality they are simply trying to ensure they don't get trapped with an app that can't grow with their needs. I have found that there are actually very few places where a design like this is needed. I can almost always create a design that addresses the expansion desires of the client without putting them into the role of database designer.
"The system to be built will allow user to add new columns to a table in the system..."
Really - that's the user story? Sounds like you've already made up your mind on the solution, to me.
Whether it's a good idea or not to allow a user to extend schemas is pretty context dependent. I'd have little problem in an admin-like, limited use way. But it'd be a horribly bad idea in a MySpace type way. I suspect your situation lies somewhere between those 2 extremes.
Extending the schema would lead to greatly more efficient queries - as you could add indexes and such - but it does expose some relational rules on your users. Also, the extension would (probably) lock the entire table and concurrent edits would need to be dealt with.
If this is centrally hosted by you, I would suggest NOT allowing user-input data to change the schema of the database (i.e. drive the creation of new tables).
Rather you may want to look into using XML fields in SQL to store variable field names of data, or a more generic table structure... this technique works pretty well if we're not talking crazy amounts of data...
Is it possible you're looking at your solution sideways? It sounds like you need a mapping table (sort of like your #1). You have a table, say "objects" for example, a table called "properties" which holds what you're calling columns and then a table that holds the values, so it just has object_id, property_id, value.
To put in a smarter way than I said it, take a look at the Entity-attribute-value model.